I have a 1998 ford f150 with the towing package. Ive had the truck since 2000 and never had the reason to tow anything until now. I have the 4 wire plug on the round housing but the is no voltage when I press the brake or the blinkers. I have remove the 4 wire adapter and measure power in the round housing with no luck. I thought it might be my meter so I hooked the trailor up ...and no brake lights. I can hook it up to another truck and they work. Ive checked all fuses...in both boxs (the one under the hood) and all are ok. Iam I missing something here ?? I traced the brake wire from the wiring harness and it goes to the front of the truck in the wiring loom. I wonder why Ford would send the wire all the way to the front of the truck when they could tap into the brake wire at the light ??Any ideas ??? Any other places to look ?? Thanks for any help.

 

When you say you checked all fuses, which ones specific to the trailer did you check ?
The factory tow kit has a relay kit that needs to be installed, and you might be short a few fuses, if it was not installed by the PO.
Ref you owners manual for the compete description on each fuse.

CJB ( Central Junction Box = Inside the cab )
Fuse #18 : 5 AMP
Fuse #23 : 10 AMP Powers the Trailer Tow Battery Charge Relay

BJB ( Battery Junction Box = Under hood, primary fuse box, not the Aux ).
Fuse #1 : 20 AMP : this powers the trailer tow running lamp relay
Fuse #16 : 40 AMP : Feeds the trailer Tow LEft and Right Turn Relays

3 Relays are :
1. Trailer Tow Left Turn Relay
2. Trailer Tow Right Turn Relay
3. Trailer Tow Battery charge relay ( not important for you problem, just something to be aware of )

Engine Fuse Module
Fuse #2 20 AMP : Takes power from Fuse #16 BJB and distributes it to one side of the N.O. contacts on the L&R Turn Relays

The wire is run from the front of the truck ( for the trailer tow ), as it is a seperate circuit for the trailer, for the turn signals, and the brake circuits.

 

Great info....I checked all this fuses you listed and all are good. They dont list the the relays you listed in my owners manuel. Where would they be located ? Also the#2 20amp Engine fuse module which fuse box ?

I now understand why they ran the wire up front. Thanks

 

That is the little Aux fuse block just behind the BJB in the engine compartment.
Here is a picture of sarebaugh's on his 1998, the little red box in the upper right hand corner of the picture.

https://www.f150online.com/galleries...1573&anum=2028

The Fuse I listed above is the Yellow 20 AMP, just behind the 7.5 AMP fuse.

The Relays are marked as being in the fuse box under the hood of the truck :

https://www.f150online.com/galleries...028-161574.jpg

https://www.f150online.com/galleries...028-161575.jpg

Start with checking the Little Aux Fuse block, I do believe that was the hold up on sarebaugh's 1998 for his S/T/T lamps not working.

Start of the thread on it, a lot of it was done over email.
https://www.f150online.com/forums/sh...hlight=trailer

 

BINGO !!! Thats alot SSULLY !! Blown 20amp fuse. I learn alot about my trailor lights . Thanks again.

 

For the future, here is the wiring diagrams for the trailer Tow :

EVTM 95-2 :


EVTM 95-3: