Blinkers dont work

[HotRodPC]

no flashers.

I'd certainly check the flasher bulb(s) first. Sometimes 1 operates both turn signals and flashers, sometimes they each have their own. All depends on how the vehicle is wired. I'm a bit more familiar with the later model multi function switch models. Yours is not a MFS truck. MFS is 84 and later.

 

[theblindchicken]

I'd certainly check to make sure the flasher relay on the fuse block is operating correctly. If it is, then check for 12v on the block.

Have you checked for any blown fuses yet?

 

[HotRodPC]

I'd certainly check to make sure the flasher relay on the fuse block is operating correctly. If it is, then check for 12v on the block.

Have you checked for any blown fuses yet?

Yup, that's what I'm talking about. Start with the easiest and cheapest. If that's all good, then I'd suspect the switch in the column.

 

[chengny]

Anyone else confused by this exchange?

Terry asks a two part question:

1: Do the brake lights work? And 2: Is there a difference between front blinkers and rear blinkers? The rear blinkers and brake lights work on the same wires as I mentioned before. That will help diagnose if it is a wiring problem after the blinker switch.

The kid answers:

The switch moves but nothing happens. And the rears work fine but the fronts also turn on.


He seems to answer only one question. What does he mean by "the rears work fine but the fronts also turn on"

The front and rear what's? Maybe he's installed a set of those new "front end brake lights". O'Reilly's is selling them as a package deal with the blinker fluid - buy a set, and you get 50% off a gallon of BF.

This was the problem was originally described:

My blinkers don't work but every time the brakes are applied the lights come on?

That is SOP. When the brakes are applied, the brake & rear blinker lamps should light up - because they are one in the same bulb. The brake lights are illuminated by default on both sides. They are only overridden when the hazard flashers or on the side that a directional signal is activated. But I'm preaching to the choir here - we all know that.

The only thing I can think of that he means is - that when the brake switch closes - not only do the common filaments for the brake/flashing lamps in the rear assemblies light up, but the directional filaments in the front parking light assemblies do so as well.

The power supplies from the brake light switch and the pulsed power from the two flashers (hazards and directionals) are well protected - by being inside the cab - and are kept isolated from each other up to and through the MFS. I don't mean to be insolent Mr. HRPC, but I checked the parts lists and wiring diagrams, and a rudimentary MFS was in use in 1980. It was just a directional switch really, but it did also control the function of the hazard lights, brake lights directionals and horn:

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Anyway, it seems that there is a cross-feed situation somewhere between the two circuits - but on the load side of the switch. It would be a stretch to imagine it existing on the line side because of the protected in-cab conditions or that the switch itself had failed. I know they do fail, but usually not in such a manner that it would allow the brake light power lead to come in contact with the directional circuit.

It's probably time to break out the Fluke meter and start ringing out the cable run from the rear rear lighting assemblies to the firewall transit block. I'm going with something simple that will jump right out at him - like the harness is pinched or melted by the exhaust system.

But, I have been wrong before - I think it was back in 1994-5.

 

[Iowan]

The brake light power goes thru the turn signal switch before going back to the tail lights. That is so when you have the brakes applied and the turn signal on it will blink. The turn signal switch is inside the column under the steering wheel. There is a good write up on here from 89 Suburban with pictures on column dis-assembly.

Try checking wiring before getting into that but its not that hard. I borrowed a steering wheel puller and lock ring tool from an auto parts store to do mine.

I will have to do that.

 

[Iowan]

Do the brake lights work? Is there a difference between front blinkers and rear blinkers? The rear blinkers and brake lights work on the same wires as I mentioned before. That will help diagnose if it is a wiring problem after the blinker switch.

The brake lights work.and OK I will check it out.

 

[Iowan]

So when you move the switch do any lights come on? If yes which ones?

none of them.

 

[SkinnyG]

I lose my signal lights when the prolific rust stops the tail light ground from connecting. I usually have to pull the taillight housing off and much with it by the side of the road. I really should make a better ground.....

 

[Iowan]

I lose my signal lights when the prolific rust stops the tail light ground from connecting. I usually have to pull the taillight housing off and much with it by the side of the road. I really should make a better ground.....

with this truck rust could be very likely.

 

[Georgeb]

Check the fuse. Do the reverse lights work? They appear to be on the same circuit. Then try a new flasher relay. After that the power is fed to the plug on the column for the turn signal switch by purple wire. Do yourself a favor od go get a haynes manual at the parts store. It's not the best manual out there but it will be very helpful. They have basic wiring diagrams in them.

 

[boostdtalon]

I lose my signal lights when the prolific rust stops the tail light ground from connecting. I usually have to pull the taillight housing off and much with it by the side of the road. I really should make a better ground.....

I ran a ground to my frame after a cop let me know my taillight didn't work at all.




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[Iowan]

Ill have to check it all out.

 

[75gmck25]

I've gone through this troubleshooting before, so I have some simple checks.

- Check to make sure the black instrument panel ground wire is connected to the post on top of the emergency brake mechanism. If this ground is disconnected, your instrument panel finds all kinds of other ways to connect to ground, which really screws up the instrument panel lights and gauges.
- At the front of the truck make sure there is a ground to the radiator support for each side. That wire is usually very easy to see on the driver's side, but may be right next to the battery on the passenger side.
- At the back of the truck in the middle, just under the edge of the bed there should be a white ground wire that connects the wiring harness to the bed and to the frame.
- At each taillight there is a ground wire to the truck body.

Check all these first, since if any of them are missing it makes it very hard to do other troubleshooting of the lights.

Bruce

 

[74propu]

Calvin if you step on the brake pedal dose the front turn signals light up???
if they do take apart the rear lights take the bulbs out and inside the sockets there will be a small copper strip down the side look and see if they are still there or have broke off ?? if missing a copper strip replace the socket with a new one from the parts store then recheck front lights with brakes on if they don't come on replace the 552 flasher in the fuse panel and check for turn signals
some times the little copper ground straps in the sockets brake off and the lights will back feed to find a ground and pop the little flasher in the fuse panel

 

[theblindchicken]

Any luck finding the source of your issues?