So i rewired my utility trailer tonight and during the checkout noticed the my trucks lt brake light wasn't working. no biggy just plug in a new bulb right? nope. The left brake light on the truck and the trailer are both out. All other functions normal, turn, running lights etc

Will get back on it in the morning.

Any body know of a common place for brake light wiring to be an issue???

 

i don't recall at the moment but i think there fused. might be a simple fix.

 

left and right fused separately?

 

i believe so, but i could be wrong too! check the lamp holder they start to degrade over the years and the plastic gets brittle or loose contacts internally

 

If neither the Truck nor Trailer work, it most likely will be a Circuit issue.


I am not familiar with anything other than the Headlamps being independently fuse protected.


There are several connections. I suggest you begin with a wiring diagram.


There was a post sometime ago with a similar issue. You might try searching for that to gain some insight.

 

So far I have verified that the wiring from the engine bay to the back of the truck for both the left rear truck light and the trailer light are good.

Only wire diagram I can find shows the signal coming from the multi function switch. The brake switch at the pedal uses one wire to supply the signal to the multi function switch then it is split there to left and right. Anyone know where this multi function switch is? (also controls left and right turn signals and hazards).

Anyone have a wire diagram for a 2000 f250 that will show the trailer system wiring? I assume that somewhere the trailer and main signal split. If I can find that splice it would help. Anyone know where to look?

Thanks, Paul

 

The "Multi-Function Switch" is the Turn Signal Switch/Lever in the column.

 

Thanks Pirsch Fire Wagon, saved those for future needs.

So like I said this started with a trailer rewire. While I had the wire tools out I decided to change the 4 way plug on the truck as well. When I was checking every thing out I turned the key on and tried the blinkers, right first then left. I turned the key off while I went into the shop to grab the stick I use to put between the seat and brake pedal when working by myself. Came back and that's when I found the left brake lights out.

Next day and several hours wasted trouble shooting later I go to pull the column covers off to access the multi function switch. Turn signal looks funny??? guess who left the turn signal in left turn and turned the key off. ........ if you look at the multi function switch diagram you see that when you select left or right turn it removes the brake signal from that side.......DUH.

Maybe this will help some one else save some time in the future...oh well

 

We have all been there!! The simplest things are often over looked. Glad you got it figured out, with just a little headache to show for it!