howdy guys,
My 1996 XLT has a factory trailer light plug connector that has a pigtail to a standard flat connector. It has always worked well on the trailer, until the right side trailer stop/turn lights started acting up. I found a short in the trailer frame wiring to the lights that I fixed, but it didn't help the situation.
I was hoping it was a simple fuse, but there was no blown fuse in either the power distribution box nor the fuse panel located in the cab near the steering wheel.
After some looking around on the internet, there is perhaps an AUX RELAY BOX, or several of them, that has some relays that seem to control the trailer tow lights, but I have no idea where those relays are. It seems like every year Ford changed the location of these relays.
If anybody can tell me where to start looking for the trailer tow AUX relays I would greatly appreciate it. Likewise, if there is no such thing, I would appreciate that info too since it would keep me from having to tear apart the engine compartment or some other really whacky place where these things are hiding. Dang, it was a simple 4 wire plug that turned into a nighmare.
Thanks for your help
Eric

 

Per the factory service manual for the 1996 Explorer, the left and right trailer tow turn signal and stop lamp relays are located in Aux Relay Box #1. The trailer tow park lamp relay is located in Aux Relay Box #4.

Aux Relay Box #1 is located on the LH side of the engine compartment. This would be under the hood on the driver's side.

Aux Relay Box #4 is located in the left rear of the vehicle, behind the trim panel above the rear wheelwell. You'll probably need to get to this from a little access door in the left rear trim.

-Rod

 

Thanks for the info Rod. You are exactly right on the Aux Relay #1, but I would like to get my hands on the Ford engineer that mounted it behind the battery and under the trim flange! I haven't had a chance to locate #4, but I am sure you are spot on. By chance, in that service manual does it show a diagram for what relays or fuse are in each?
Thanks again, great forum and all your help.
Eric

 

Yeah, the mapping for the various fuse and relay blocks are listed in the service manuals. Often they are mapped in the back of the owner's manual as well, but I'm not sure Relay Box #4 would be mapped in the owner's manual.

-Rod

 

If you download the 1996 Explorer owner's manual from here and review pages 390-391, you'll find mappings for the relay boxes. Interestingly, this manual refers to the rear relay box as "#5" versus the "#4" designation from the service manual. Since your truck is an XLT I'd suspect you have the 4 Door High Series.

-Rod

 

Hi Rod,
Can't thank you enough for the link to the manual. That is exactly what I needed. How would anyone in their right mind would think that is easy to troubleshoot! Well I guess that it's been almost 20 years with her now, and this is the first problem with the lights. I hope that it's just a bad relay that can be easily replaced.
Thanks again Rod, I really appreciate it my friend.
-Eric

 

I don't think this will come as a surprise to you, but I really doubt "ease of troubleshooting" was on anyone's mind when laying out the wiring harness. It was probably more like "minimize cost and weight by reducing the amount of heavy gauge wire."

Good luck and please report back with what you find!

-Rod

 

Hi Rod,
Just wanted to update my progress on my trailer lights. With your help, I located all the relays that control the trailer hazards/stop/turn in the AUx relay #1 located behind the battery. Once I got to it, the Left side was working fine and the right relay was dead. Tested the relay and it checked out ok. Further troubleshooting determined that there was no power to the relay coil itself when called for.
This led me on a goose chase to the Multifunction switch wiring, as the schematic that I have that controls this relay comes from there. I am hoping that perhaps it is a loose wire in the connector that plugs onto the switch itself. I looked around and there are several Multifunction switch diagrams out there, and as typical with the Ford engineers, they changed it from year to year. I am pretty close with a '98 schematic that I dug up, but if you have or know of the pin-out for the 96 connector that would help me again.
Getting closer, just don't know how the shroud is going to come off the steering column without tearing apart the dash!
If you have any schematics on it I would appreciate it, otherwise I'll try to wing it with the version that I found.
I would post pictures but I am not allowed yet.
Thanks
Eric

 

I have the service manual for the 1996 at home. I should be able to get a copy of that late this evening. If you send me a Private Message with the request and include an e-mail address for you I can e-mail you what you should need.

-Rod

 

Thanks for taking your time, my email is e_glaude@yahoo.com. I'm hoping that it's a pin that made it's way loose from the connector. Could be a bad switch too, who knows.
Thanks and take care.
Eric

 

The files are on the way to you.

-Rod