Turn signals only work once truck is warm

[Dylandeuceman95]

Hello everyone, little stumped here. Since I got my truck about a month ago it seems the turn signals only start to work and blink once the truck has ran for about 15 mins. If I flip them on when trucks cold the indicator blinker light will come on solid and the outside lights will not blink until truck is warm, then both indicator and turn signals will blink as supposed to. I put a new switch in it and still the same thing. All other lights work whenever commanded to do so. It’s only the turns that are being weird. Any tips or thoughts are appreciated. Thankyou!

 

[Barrman]

One of my trucks does the same thing, sometimes. I am convinced it is my blinker box/relay. Here is a video about how to test the flasher box:

I live down a dirt road and have learned with that truck to just turn the blinker on when I start the engine. If it works, then it will probably work the rest of the drive. If it doesn’t flash, I just leave the blinker arm full left or right while I idle toward pavement. It will normally start blinking like it should before the end of the dirt.

 

[HDN]

@Dylandeuceman95 have you noticed if the outside weather or air temperature affects how long it takes to start working? I was wondering if there were mechanical contacts that are worn out and only work if they've expanded a little bit due to engine compartment heat.

Dumb answer: Maybe the blinker fluid hasn't been changed? Have you had oil analysis run on it? (Sorry I felt this was a good time to bring it up.)

 

[Dylandeuceman95]

@Dylandeuceman95 have you noticed if the outside weather or air temperature affects how long it takes to start working? I was wondering if there were mechanical contacts that are worn out and only work if they've expanded a little bit due to engine compartment heat.

Dumb answer: Maybe the blinker fluid hasn't been changed? Have you had oil analysis run on it? (Sorry I felt this was a good time to bring it up.)

lol yea I’m thinking it’s definitely related to a contact of some sort expanding and making contact once it’s warms up the connections a bit, but if not in the switch, what else is there?

 

[Dylandeuceman95]

lol yea I’m thinking it’s definitely related to a contact of some sort expanding and making contact once it’s warms up the connections a bit, but if not in the switch, what else is there?

Maybe it’s in the lighting switch itself. Upon further review of the diagram it looks like it has wires running through the main light switch. May have just answered my own question…. I’ll pry replace the main switch and report back with my findings.

 

[HDN]

lol yea I’m thinking it’s definitely related to a contact of some sort expanding and making contact once it’s warms up the connections a bit, but if not in the switch, what else is there?

I believe there's a flasher unit in the engine compartment somewhere. I don't know the location offhand as I've never had a reason to look for it. I'm pretty sure the old ones are mechanical. There are newer solid state ones, but it seems the newer replacement ones have longevity problems.

 

[HDN]

I just checked my M35A2 maintenance TM. The flasher unit should be located inside the left front fender (driver side). Please see attached PDF.

 

[Dylandeuceman95]

I just checked my M35A2 maintenance TM. The flasher unit should be located inside the left front fender (driver side). Please see attached PDF.

All very good stuff guys, I’ll look into that flasher box. That pry makes more sense than the main light switch