Turn signal / wiper wiring

Hello,

1986 F250 6.9: Since my wiper switch was barely working and required lots of wiggling while driving (not safe...) I replaced it with a new part. It nominally has the intermittent function and therefore has a black ground cable so I spliced it on to the original part's ground cable.

Or so I thought.

Because now I don't have turn signals or back-up lights! Fun times.

Now, I grabbed a flashlight and stuck my head down by the pedals and found out that the cabling under the dash is the stuff of nightmares. The previous owner(s) had an absolute field day twisting wires together and then wrapping them badly in (now peeling) insulation tape, butt connectors and so on.

Here's some details:
*Here's the new switch I put in. Note the black cable. It matches the original.
*Among all the cable spaghetti I can't find the original wiper ground cable. I grounded the new switch to a decent - but new - ground connection.
*When I turn on the ignition my tail lights light up (even with the running lights off). They seem dim to me, though.
*The turn signal fuse tests fine for continuity.
*My emergency flashers work fine. (These are on a separate circuit, it seems.)
*Headlights and regular running/tail lights work.
*The wipers seem to work - although intermittent doesn't. Maybe not both speeds?
*The truck has an old Takonsha Mk. 12 solid state trailer brake controller installed - but it doesn't seem to be hooked up. Or it's kind of hooked up, some cables are connected, some aren't.
*Turn signals, tail lights etc all worked just fine before I delved in.
*I note that the dim tail lights go out when I move the stick to turn on the turn signals with the ignition on (not that the turn signals end up working).

Basically my questions are:

>Where do I start?! I haven't been faced with a ground/lighting issue like this before and not sure what first steps might be. I'm presuming the turn signal wiring went through or was split to the Takonsha unit but I'm unclear of what wire is what.

>Is there any chance the wipers shared a ground cable with the turn signal....? And I cut it when I tried to splice the new wiper switch?

>Does the wiper control switch black ground cable need to go to a specific location? Or will any good ground work?

>A wiring diagram would be wonderful - does anyone have one?

>Is there any other place I should be looking - anything that seems peripheral etc but might be a factor?

>If I leave the ignition on while I poke around with a multimeter, the glow plugs are cycling. Will it do any damage to let them keep cycling for a few minutes?

Yep, I'm lost on this one!

As usual, thanks in advance.

Well I did find something that looks a lot like this photo (from the web) under the dash. My new switch is plugged in to the red connector and grounded to a ground point. Does this tell me anything? Are these after-market or original equipment?

Guessing I can bypass this box by finding the original plug, thereby also bypassing a potential ground problem I've created? Hmm.

That box is what runs your intermittent wipers. It’s original equipment

It is nigh impossible to diagnose such wiring problems "over the phone" so to speak.

As for "Grounds", most of the stuff under the dash does not have a Ground wire unless the previous owner was like me and added them (I don't trust "chassis Grounds")

I am a self-proclaimed expert when it comes to vehicle wiring and the factory wiring of the wiper switch baffles me; nothing does what you would expect it to.

Did all these things work before you spliced into that wrong wire ?

Were I you, the first thing I would do now, BEFORE I did anymore wiring, would be to un-splice that wire and put things back like they were before I started and see if all those new problems went away.

There is one wire on all these Ford trucks that causes a lot of mysterious electrical problems and makes all sorts of funny things take place, different from one truck to another.

If it has not already been taken care of many years ago, amongst that bunch of wires coming out of the left-upper corner of the fuse-block is a Tan wire of about 20-AWG that Ford expected to do the job of a 4-AWG cable.

Pretty soon in life, that wire gets so hot as to melt itself out of it's insulation.

Then, being always so overly hot, it starts melting itself into the insulation of other wires, making things turn ON when they shouldn't, making things not turn ON when they should, and killing some things for good.

Not to confuse the issue, FIRST, back-track yourself and undo all the things that you did and see if all your new problems go away.

Then, before doing any other wiring, look to see if you have a wire that used to be Tan that is now naked and melting it's way into other things; if you find such a wire, find where it begins (the fuse block if I remember correctly) and where it ends (the headlight switch if I remember correctly) and completely replace that tiny wire with one much larger, 12-AWG would be my choice.

I cannot stress the importance of good record keeping enough --- DOCUMENT every little detail of everything you do --- as you do it - while you still remember what you did --- so you can refer back to this information when trouble-shooting something else later.

One other point = unlike house wiring, there is no such thing as a universally accepted wiring color scheme where vehicles are concerned; people, including vehicle manufacturers, use the color of wire that they have on hand when the project is done; if all they have is a big roll of Green wire, then every wire on that project will be Green, regardless of where it is going and what it will do when it gets there.

Avail yourself of a bunch - many packages - of those Harbor Freight many-colored key tag label thingies with the see-thru window and the little piece of paper you slide out, write on, and slide back in.

When you identify a wire, or add a new wire, select two of these tags that are the same color; write down what the wire is on your little label; then, zip-tie - using both holes - your nice new identification tag to both ends of the wire, one tag where it starts and another tag where it ends.

Now, make a note in your documents as to which color of tag you used and what color zip-ties hold it to the wire === this is one situation where I do not cut away the "tail" of the zip-tie, but leave it hanging out there to better be seen and found later.

I hope some of what I have said here is of some benefit in your endeavors.

Rupert8 said:

I'm presuming the turn signal wiring went through or was split to the Takonsha unit but I'm unclear of what wire is what.

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Turn signals should have nothing whatsoever to do with the brake controller.

The brake controller should have four wires = Always HOT - Always Ground - OUT to the trailer brakes - IN from the electronic gizmo you supply at the Cold Side of the Brake Light switch ----- without that little electronic gizmo, on these trucks, your electric trailer brakes will surge with every flash of the turn signals --- EVEN THOUGH your turn signals never connect to the brake controller.

Most people's electric brakes are so weak and useless that they never notice this surging.

Rupert8 said:

>Is there any chance the wipers shared a ground cable with the turn signal....? And I cut it when I tried to splice the new wiper switch?

Click to expand...

Not possible that I can envision as the turn signals Ground at each bulb; on a factory set-up, there is no "Ground" for the turn signals anywhere else.

Now, if you have dis-owned that wimpy factory mess in favor of a big genuine Signal-Stat, they do have a Ground wire that Grounds the little indicator lights within the switch itself.

MIDNIGHT RIDER said:

Turn signals should have nothing whatsoever to do with the brake controller.

The brake controller should have four wires = Always HOT - Always Ground - OUT to the trailer brakes - IN from the electronic gizmo you supply at the Cold Side of the Brake Light switch ----- without that little electronic gizmo, on these trucks, your electric trailer brakes will surge with every flash of the turn signals --- EVEN THOUGH your turn signals never connect to the brake controller.

Most people's electric brakes are so weak and useless that they never notice this surging.



Not possible that I can envision as the turn signals Ground at each bulb; on a factory set-up, there is no "Ground" for the turn signals anywhere else.

Now, if you have dis-owned that wimpy factory mess in favor of a big genuine Signal-Stat, they do have a Ground wire that Grounds the little indicator lights within the switch itself.

Click to expand...

This is awesome, thank you. While it's not a definitive solution - which, like you say, won't be possible remotely and also because someone has been under the dash and gone nuts with butt connectors (or not, in the case of dangling wires) - it has helped me understand a lot and rule things out.

Can I ask for clarification on the 'electronic gizmo' you mention? Asking because I reconnected the brake controller to the wire (badly) connected by the previous owner to the brake light switch. Not sure what the electronic gizmo you refer to might be here.

I do have a mystery silver box under the wiper control switch which seems to have some cables connected indirectly to the brake controller - and other disconnected cables not.

Yes, all worked fine until I tried to splice in the wiper switch. I'm surprised to hear it's original equipment @THSIM9 , thanks. I believe I have the wiper switch connected back to the original wire now. But I'll dig more this evening, and send on a photo of the box I mention if possible.

Just seems so odd that the back up lights and blinkers don't work now.

Worth mentioning, the brake controller LED used to activate when I pressed the brake pedal - of course - but also when the blinkers were on. That's why I thought it was connected to the blinkers somehow. Does that tell me anything?!

The only other change i made yesterday was to replace the dash instrument bulbs (one of which had blown) with LED ones. The L and R green dash arrows still have incandescents. The actual front and back external tail/blinker bulbs are LEDs, but they worked fine for months before this. Again, the hazard blinkers work. Just not the turn signals or back up light....

I had a brake controller just like yours in my truck when I got it...I took it out and all of the wiring that was connected to it and set it aside for later...I removed everything that did not look like 'factory'...

Then...I looked under the rear area of the truck and saw the gol-durnest looking web of crazy stuff in there and then went and got my diagonal cutters, wiring pliers, and lots of cardboard to lay on and...with a big sigh...got comfortable and just did what needed to be done...

I cut all of that crap out of there with lots of vim and vigor...removed an old six-round trailer wiring receptacle and cut everything on up to where the original wiring was un-molested...

There is a moment of hesitation when you have a 'bad' wiring job in your right hand...and the big, evil diagonal cutters in the left...and you just 'know' that 'this' is the no-return moment when 'everything' from here on out changes...

Sort of like that first-coffee date with the gal that you hope will finally be 'The One'...

I went for it ....

Sure...I just fixed it so I could not drive the truck right away...but I resolved to fix this thing 'right' once and for all....

I gathered every bit of automotive wiring and connectors, trailer wiring components and misc. stuff I had and laid it all out and organized it so I would use what I had first...and then buy what I needed once I formulated a plan...

When I bought the truck and later investigated what was left in the toolboxes...LO and BEHOLD...a nice RV receptacle and accompanying wiring harness was already in there...looks like the PO was going to fix it and just gave up...

I took time to make a few lists and charts...wiring color and function...(pictures and charts actually help)...and then set about to graft things together in a neat, tidy, and (hopefully) trouble-free way...

I figured that I had better things to do once I began driving this thing than to agonize about any wiring problems...especially if I was going to tow any heavy load at night...we don't need to create any new problems...we got a loaded plate already...

On the brake controller that dated back to the early 'nineties '(the same as yours...)...my gut feeling was to not use it...and I was right...I found later when I took it apart that it was full of dirt and dust, corrosion and crud...it would have been trouble...

I found that I had a 'new' in the box controller that was over ten years old...but it had the instructions on installation...and more importantly...how to tune it in for various loads...I put the instructions in the glovebox for safe-keeping...

I had...over the last coupla decades...accumulated a small mountain of wiring stuff...but still needed to get a few items to make it happen...the best thing was that I had all of the right color wire in the right size for the loads...now the leftovers are sorted in ziplock bags and stored in a bin with a ratchet strap keeping the lid secure...

I wired the brake controller so that it has an 'arming' toggle switch...I only use it when I need it...it does not have constant B+ going to it so no little light is on when I don't want it...

The tail light harnesses are wrapped in corrugated conduit...with copious amounts of black tape keeping it all secure...

Works like it should...

So...if it were me...and my advice to you...is...

Ditch the brake controller and get a good one...just do it...
trailer brake function is not to be fooled around with...

Cut (carefully) cut out anything that was spliced in there and find and repair and even add some grounds...you are going to need them...

Get under the back of your truck and see what has been 'done' to it and just follow my lead on it...you need the truck to be solid and reliable...no matter how much you gotta do and however long it takes...

And when you are done...you will know your truck better and also know what you got...

Just my two cents...

P.S. you should be able to find enough wiring diagram info on this site to help you do this...as a matter of fact...I think looking for wiring info is what got me on this site in the first place...

Thanks a bunch, guys...

Rupert8 said:

Can I ask for clarification on the 'electronic gizmo' you mention?

Click to expand...

On my truck, it has been under there since almost the day the truck became mine in about 1986 or 87 and I can't recall just what it was called.

The actual little gizmo that does the deed is a tiny little thing that is mounted through an angle bracket via an insulator; one wire goes on the top and the other on the bottom.

I would have to lay under there and look; but I sort of want to think that, instead of the brake signal wire passing through this thing, this thing "y"s off the signal wire to Ground.

Google up "turn signals cause my electric brakes to surge" and it will probably come up.

Like I already said, most people's electric brakes are such a useless joke that they probably don't know they need this device.

I have electric brake capabilities on all my trucks for those times when I pull someone else's trailer that may have electric brakes; but, we all around here gave up on them years ago and have RedLine Vacuum-over-Hydraulic kits on all our trucks and big huge vacuum boosters under the necks of the trailers and big dual-chamber master-cylinders feeding genuine hydraulic brake axles.

It is reassuring and also head-turning when I apply the brakes and that big thing under the trailer neck makes that loud sort of groaning racket and the trailer nearly jerks the truck backwards.

All my trailers have Dana axles, so my trailers use the exact same brake shoes and internals as my Dana equipped trucks.

I guess you can gather that I am not a fan of electric brakes.

Rupert8 said:

Just seems so odd that the back up lights and blinkers don't work now.

Worth mentioning, the brake controller LED used to activate when I pressed the brake pedal

Again, the hazard blinkers work. Just not the turn signals or back up light....

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It sounds like you blew a fuse or two when you spliced into that wrong wire.

Can you tell if your brake lights are working ?

I recently put myself a little red LED under the dash that lights up the floor-board whenever the brake pedal is pushed; thus, I have a constant indicator of whether my brake lights are working or not.

I have a Harbor Freight test light that looks like a big long screw-driver with a telephone cord on it; that thing sure pays it's keep when troubleshooting.

I went on a vast pilgrimage to completely get rid of that factory fuse block and get all my fuses and circuits relocated to places where I can stand on my hind legs and see what is what.

Ford is not alone in this; all manufacturers use much too small of wire and try to cram too many things in too small a space.

You guys talking of being bewildered and hacking away at non-original wires would really be lost looking anywhere in and under my truck; Wolf Creek Dam hasn't got as many wires and circuits as I have --- and --- every last one of them works 100% of the time or I will move heaven and earth finding out why not.

I have long ago lost count of how many big toggle switches are in and around my truck.

This is on the cab wall behind the passenger seat.

There are four of these in the left side doghouse under the sleeper; besides sleeper accessories being fused there, each string of truck markers get fused there such that, should something happen to one group of markers, only that group is lost, the rest remain lit up.

There are two under the dash beside the column.

There are four in a box under the hood where the right-side battery used to live.

There are big house-type gutted breaker-boxes under the trailer necks with four of these in each with each separate string of lights fused independently; if a cow somehow knocks out a circuit, the only lights lost are those on that fuse; the rest of the trailer remains lit; there are more than a few lights on the trailer.

Here you can see how I use key-tags to identify wires; I need to get the rest tagged.

So long as I have my diagram, the color-coded zip-ties tell me what is what; but, the key-tags tell me at a glance.

Thanks again. Really appreciating this. @XOLATEM, it's hard to argue with cleaning this all up. First goal is to find the damn problem and then, I know myself, I have to scratch it, can't leave it alone..... I'm going to tidy this thing.

My concern with cutting wires after the horrible wiring jobs done by the previous owner is that I can't be at all sure what I'm cutting.

One thing I've just noticed is that with the engine running - not just the ignition on - the blinkers (and back up light) work, although they take a long time to actually start blinking. OK then..... BUT the tail light at the back on the side where the turn signal is working is also on full time. Why?!!

So something isn't right. Can I learn anything from this? Front running light doesn't stay on, it looks like it should when just the blinker is on.

@MIDNIGHT RIDER I like the LED idea. A lot. Easy to do as well. No, I didn't blow any fuses. Hmm. I believe I have wires back where they were but in this spaghetti mess it's hard to be sure. I'm not finding voltage over 0.02v at any ground point I can see.

One other thing - the green arrow bulb on the dash never goes out now: It's always on dimly now when the blinker stick is pushed up or down, and gets brighter when the blinker flashes. It's off when the blinker stick is in the middle.

With the engine running, then, I get slow-to-activate turn signals but also a tail light always on and the green arrow bulb on dimly.

Again, thanks. This thinking-through process is really helpful.

If you're worried about your glow plugs, you can remove the plug from the top of the controller. They won't come on that way.

One question I keep coming back to - since the 4-way hazard flashers are on a separate relay and circuit, is there any way of isolating the ground etc for the turn signal circuit?

The more I look into this, I really don't think I changed anything when installing the wiper switch. Obviously some thing has shifted, though. Really puzzled, and need to figure this out. The turn signals taking a long time to come on is an issue I want fixed as a priority.

Another question: Going down the rabbit-hole online, some are saying the tail lights ground is at the front of the truck, or at the cab. Others say it is direct to the frame at the back - which doesn't make sense to me. Any input?

Boy, this truck....

Just a heads up to watch for it; I made a post with a photo several hours ago that is awaiting approval.

As best I recall, the hazard flashers don't have a fuse, but a fusible link; they have their own two-prong flasher hidden on the back side of the fuse block.

About fifty things are happening within the turn signal switch; it divides where power gets sent depending on which way you decided to turn or not.

No turn indicated = both brake lights light up.

Whichever way you decide to turn flashes while the other side does what the brake pedal tells it to do.

It will flash one side or the other front lights; yet, these lights are not affected by the brake pedal.

I hate to tell you to dig in and then me be wrong; but, I kinda suspect with your other problems you have a bad turn signal switch.

One way to find out is to "bench test" it by disconnecting it's plug under the column and applying a Hot to what would be Key-On=Hot and using a test light, see that each selected position lights up the proper terminals and none that it shouldn't.

More than one test light would be real handy doing this.


You also could have a bad/weak battery connection somewhere as that will make the electrics do all sorts of funny things.

I fooled around the other night and somehow managed to turn off my alternator isolating solenoid from my accessory battery and ran it way low, like 4-volts, and I had a light on the dash to come on that I had never seen before in all the years I have owned the truck "Fasten Seat Belts"; it stayed on until I figured out that the solenoid had gotten turned off; turned the solenoid back on and voltage immediately went from barely 4-volts to nearly fifteen and that mysterious light went out; I didn't know I even had such a light.

I believe you have more than one issue taking place at the same time; check and clean up all your battery cable connections and ascertain that your battery is up to par; maybe connect a really good set of jumper-cables to the junction at the solenoid(HOT) and a clean bracket on the engine(Ground) and then to the respective posts on the battery and see if things behave any better.

Make sure that braided Ground cable between the engine and cab is in good order; that would be a good place to put your Ground jumper-cable.

Fifty things just don't all go wrong at once if those things were working before is what makes me suspect low current.

Rupert8 said:

One question I keep coming back to - since the 4-way hazard flashers are on a separate relay and circuit, is there any way of isolating the ground etc for the turn signal circuit?

Click to expand...

All these Ground at each individual bulb, wherever that bulb may be; if they Grounded anywhere else, it wouldn't be a circuit.

One leg of each bulb is the Positive/Hot connection and the other leg continues the current path to Ground.

Rupert8 said:

The turn signals taking a long time to come on is an issue I want fixed as a priority.

Click to expand...

And that is part of why I am beginning to think you have a low current issue --- or a bad switch --- but I suspect low current more.

Rupert8 said:

some are saying the tail lights ground is at the front of the truck, or at the cab. Others say it is direct to the frame at the back - which doesn't make sense to me.

Click to expand...

At the rear of the truck, under the left side of the bed, hanging under there somewhere is a roundish plug/connector that has all the rear wires going through it.

On a stock factory truck there will not be very many; Ground, Tail-lights, Left-Turn/Brake and Right-Turn/Brake and not much need for anything else.

I believe you will find a Ground point on the rear of the frame in close proximity of this connector.

A lot of people tap in here for trailer lights; BUT, that is not an ideal way to handle things and is cause for many nightmares later.

The proper way to tie in trailer lights would be to use these wires as relay trigger wires ONLY, with a big separate HOT supplying at least three relays = Trailer Markers, Left Turn, and Right Turn -- I like it even better to have a separate dedicated Trailer Marker switch and wire that has nothing whatsoever to do with the head-light switch.

Your Trailer Markers should be on a big old toggle switch that sounds like Matt Dillon pulling the hammer back on his single action Army .45; not on the tail-light circuit.

When you find that connector under the bed, you will probably also find a bunch of trailer wires tapped in there as well; and, if the guy was a real loser, all these connections will be made with "suitcase" connectors (those little plastic "no strip" connectors that you squish together with a pair of pliers - they should be outlawed)

Avail yourself of an old 100-ft 16-AWG extension cord; cut off the ends and you now have yourself a test cord that will reach anywhere on the truck.

When you find that connector back there under the bed, left side, unplugging that connector will allow the bed and all it's wiring to be removed; so, to find the Ground point for all those lights, follow the truck side of that plug.

Maybe somebody here knows the color of that Ground wire and the colors of the other three wires --- no --- make that four = five wires in all, as I just remembered there will also be a wire for Reverse Lights.

It is remotely possible that Ground will be somewhere on the truck bed itself, but I highly doubt it.

If those lights do Ground on the bed, there will be a Ground also running through that connector to carry that Ground from bed to chassis/frame.