No Turn Signals - Diesel Forum

Badger174 · 08-04-2008, 02:38 PM

I lost my turn signals the other day after I hooked up to a trailer with bad wiring. I checked the number 7 fuse in the dash and replaced the flasher in the fuse panel. I even tried a different multi-function switch from my dad's truck and that didn't do it. I have 4-way hazard flashers and brake lights. Any ideas on the turn signals?

Thanks in advance,
Zach

eagleeye · 08-04-2008, 05:07 PM

Your running lights and turn signal fuses for your trailer harness is located under the hood in the power distribution box. I think they are 10 amp for the turn signals and 25 amp for the running lights.

Badger174 · 08-04-2008, 08:36 PM

It's not just the trailer, I don't have any turn signals on the truck with or without a trailer. So even if the fuses for the trailer harness are blown wouldn't that just affect the trailer?

STurbo90 · 08-04-2008, 09:54 PM

Yes, the truck lights should still work.

If you have brake and hazards the wiring has to be good up to the mfs,

you said you checked the #7 fuse, but did you actually verify there is power there? The fuse may be good, but there might not be power.

could also be a break in the wiring from the fuse to the flasher to the mfs.

Badger174 · 08-05-2008, 10:42 AM

I have power to the 7 fuse and to the in side of the flasher. So that means a break in the wiring between the flasher and the MFS? Can I use a piece of wire to jump the flasher and just check for a solid turn signal? I know that it's rare but I guess I could have gotten a bad flasher from napa?

STurbo90 · 08-05-2008, 12:12 PM

or you could just check for continuity on the other terminal of the flasher receptacle with the switch in both positions.

Badger174 · 08-05-2008, 12:13 PM

Update: I just checked the power to the harness at the MFS and I had solid power with the key in run? Shouldn't that be a pulsating voltage from the flasher?

STurbo90 · 08-05-2008, 12:18 PM

which wire? I think the light blue wire is for turn signals, there should be constant power there for flash-to-pass on another wire,

Badger174 · 08-07-2008, 06:43 AM

Yes the light blue wire. Then I checked the power in to the hazard flashers and it was a solid 12V as well and it runs on a separate flasher and I know it works. I am really stumped, I'm almost ready to go buy a new MFS but I'm pretty sure that's not my problem... And as soon as I buy a new 180 dollar MFS and put it in the truck it's mine and I can't return it?

nightbreed · 08-23-2008, 12:41 PM

I am having the exact same problem with my 2005 F250 V10. I had a trailor attached when it went, but same problems, no bad fueses,new flasher, new multifunction switch.

Did you ever resolve your issue?

Thanks,
Mike