hey guys my 1990 f-350 i am having turn signal problems with. when you turn either left or right side (yes both sides) they come on and stay on. they don't blink. they just light up and stay lit up. they never blink. i put new flasher in and same thing. i am getting juice to both sides of the flasher. I checked all bulbs and they are in good shape. i also even went ahead replaced all the bulbs with new ones just in case one was defected and still same thing. when i put my 4ways on they blink but blink rather fast. any suggestions what to check?

 

There's something in the column. Whether it's wiring or for some reason the turn signal cam is sticking and making contact, something in the column is wrong.

I'd start by yanking off the steering wheel and inspecting the turn signal cam and related parts. Maybe take it apart anyway and clean it- could be dirty and sticking and that's causing the problem.

Next you'll have to start chasing the wiring in the column.

 

When you say they come on and stay on are they lit up full bright or just kinda dimly lit?

Swap the hazard flasher for the turn signal flasher unit, a new flasher while rare might be faulty.

i am getting juice to both sides of the flasher

Is that flasher "in" or flasher "out"?

 

Good call Dan. I didn't even think about a new flasher being faulty.

Follow his advice before tearing into the column.

 

When you turn the turn signal lever to one side or another when the lights come on they are bright and stay bright on. Just as bright as they should be. I yanked out my flasher out of my truck I drive everyday and tried its flasher along with 3 others and same thing.

when I say I am getting juice to both sides of the flasher how I tested that is.
I took the flasher out. Then I turned my turn signal lever on to either side. Then I checked both wiring terminals with the flasher out. Whenever I did I Noticed both wires coming to the flasher was "hot" and both have juice.

 

so you are getting juice to both pins in the fuse box with the flasher out? hopefully if im wrong someone will correct me but it should only be 1 with juice when signal lever is switched on ( either way ) and the other is the output to the lights.. without a flasher the 2nd one should not be live.. also the flasher is a thermal style.. which once so much electric runs through it it overheats and shuts off, cools and kicks back on.. of course doing that at a fairly fast pace..
the issue seems to be in the wiring coming out of the fuse box going to the lights themselves.... its a dumb question to ask.. but do you have the proper bulb in it?? not trying to imply anything but i know a wrong bulb can wreak all kinds of havoc... it should be a 3157.. the dual filament bulb...
but if not it sounds as if somewhere you are getting a crossed wire and supplying juice when it shouldnt.. check to see if they are on and lite when they shouldnt be ( i.e. marker light setting but turn signal brightness... ignition on and light come on.. all time live ) but first take a peek at your bulbs just to be safe

 

pull the flasher out of the fuse box, and check to see if the 4 ways work. i am not sure, but i want to say you have 2 flashers in the truck, and the one in the fuse box is for the 4 way flashers.

it has been many years since i messed with blinkers and 4 way flashers on the 87-91 trucks

 

I'm pretty sure you're right about that wicked- and if there is a crossed wire, my guess is that some wires have rubbed thru the insulation in the column and are causing the problem.

Again, just to double check, make sure the flasher unit is ruled out before tearing into the column.

And let's not all forget the ever so present possibility of a bad ground.

 

Ok based on that take out the hazard flasher or fuse #1, turn signals should flash normally.

Test the theory, let us know what happens.

 

the bulbs are the correct bulbs i did check that. going out to test your theory

 

well i took out 4 way flasher. same thing still happens. so i got the idea i took out both flashers in the truck. the same thing still happened. started pulling fuse my fuse out one at a time. nothing effected it until i pulled the turn signal fuse out then instead of turn signal being stuck on. it simply went off until i stuck the fuse back in and then it was once again stuck on.

 

also yes I am getting juice to both pins of the fuse box to the flasher. i thought there was only supposed to be one side getting juice to the flasher and not the other side also. that is what i thought also. but right now as we speak i got juice to both sides.

 

No, you shouldn't have power to ground both sides of the flasher unit socket with it removed, only one side should be "hot" with the key "run" position.

With fuses 1 and 5 both "in" and signal/hazard flashers both removed there shouldn't be any power to the directional/hazard switch to power the lights, should be dead.

Only other power source to it would/could be brake light switch but it'd have to be stuck in the "closed" position or someone holding the pedal down. You'd have brake lights all the time, and removing fuse #1 would/should have killed the power via that route anyway.

Looking like you have a fried signal/hazard switch, trying to confirm it.

Both turn indicators in the instrument cluster both work right?

 

the light bulb to make the right turn signal light in the dash i think it burnt out. the left one lights up and stays on just like the outside lights do. the brake lights aren't stuck on. where is location on number 1 and number 5 fuses? in my manual it only says what the fuses do. NO numbers.

 

but i had all fuses in and both flashers out and i was still getting HOT to both flasher pins for the turn signals.