Hey all,

I recently picked up a 91 f350 with the 7.3 Diesel. All the lights work except the fender markers. Does anyone have a good wiring diagram?

I saw a thread on here for the same problem but it was a 93. I read the fender lights are on their own circuit but I'm having trouble finding where that circuit goes when it heads towards the engine compartment and which fuse they would be.

Someone who owned this truck decided to play electrician... The amount of Scotch-lok connections on trailer harness is appalling.

 

Bump?

Really just need a good wiring diagram but haven't been able to find one...

 

Just tie them into the running lights at the tail light harness. That's all there is to it. And, if you are that paranoid about drawing too much current, tie them into the trailer harness. Trailer lights are run off of their own relay.

 

It is NOT a complex wiring harness.

ONE brown wire feeds the fender lights.

Trace it

Each fender is tied into the bed harness.

 

Open your under hood fuse box and it is the 4th relay from the bottom on the right side. Should be fed by a 25 amp fuse on the left side, also 4th from the bottom, looking toward pass. side.

ETA: From my 1993 owner's manual. Maybe 1991 is similar, no experience with them.

 

he said NOTHING about the whole truck not having marker lights, JUST the dually fenders which are on the same circuit as the rest of the running lights

 

Calm down B-rad. No need to get all capital letters with me. The manual I am using shows them on a separate circuit with, and I quote, "Trailer tow and/or dual rear wheel running lamps."

 

How many of these trucks have you owned?

 

That question is completely irrelevant to the matter here, but I like feeding trolls. I've owned three, Brad. Three. Now, bestow upon me your superior ownership tally.

 

Ford may have wired it one way, but that doesn't mean it's the only way to do it. The easiest way is to splice in to the tail light wiring.

 

And that is just how it was wired from the factory

 

chillman88 asked:

That's the reason I answered how I did. Specific question, specific answer. Just trying to help the guy out.

 

Wow sorry I didn't realize this would cause such debate. I could have "made it work" but I wanted to fix it instead.

After digging around I finally found a good wiring diagram. Apparently the fender lights run through the trailer wiring relay... Luckily that's all the problem was, local parts store actually had the relay in stock and I replaced it and the fender lights work now.