99 - Fuse #11 blown, no running lights, fogs, or dash lights

[trj360]

So it's been a couple weeks and I have not blown another fuse yet.

First, I took a look at the relay box as suggested and it appears that I would have to take off the entire rear interior panel. I didn't have the patience for that so I looked elsewhere. Here is a picture of the relay box and assorted wiring for anyone who is curious.

I then moved on to my trailer wiring. There was nothing immediately apparent that would indicate that something was wrong. What I did notice, however, was that the wiring junction box was in the perfect spot to get sprayed with water from my driver's side rear tire:

I wanted to cut out the entire trailer wiring harness, but it looked like some kind of factory deal. It was wired right in with the light sockets and the junction box itself had a ground wire right to the body, no splicing or anything that would indicate an aftermarket installation, so I left it alone. After further investigation, I found where the box had previously been attached (glued or something) to the body, directly behind the driver's side tail light. I shoved it back in there and used a zip tie to hold it in place, and after more wet roads and snow, no blown fuse.

My working theory for this whole problem is that water was somehow getting in the wiring box and freezing. My fuses blew for a week or two straight because the water had turned to ice. The only thing different from the days when my fuses blew and didn't blow was the temperature - when it was above freezing, there were no problems. Looking at the box, I have no idea how or where water would even get inside, but moving the box seems to have cured the problem, at least for now. Of course I will update if I find anything else out but for now I consider this solved.

 

[koda2000]

i'm not sure what that box is. i have the factory trailer harness on my trucks and it's just a pigtail that plugs directly into the driver's side tail light wiring. 4 wires, tail lights, left turn, right turn and ground. if you don't use it you should just be able to remove/unplug it. this is much easier to get at if you remove the tail light (2 screws and pull). maybe it has something to do with electric trailer brakes, but that usually also has a box under the dash board where you can control it from.

 

[trj360]

i'm not sure what that box is. i have the factory trailer harness on my trucks and it's just a pigtail that plugs directly into the driver's side tail light wiring. 4 wires, tail lights, left turn, right turn and ground. if you don't use it you should just be able to remove/unplug it. this is much easier to get at if you remove the tail light (2 screws and pull). maybe it has something to do with electric trailer brakes, but that usually also has a box under the dash board where you can control it from.

There is no obvious way to disconnect this box. There are wires coming straight from the tail light sockets to the box, and the box does not appear to unplug in any way. I would have just cut it out if it wasn't integrated with everything.

One side of the box has input wires coming from the tail lights and wiring harness. The other side of the box has the wires that used to go to the trailer plug, but I took that off a while ago. Recently I trimmed the wires that went to the plug down just about to the junction box but that was more cosmetic than anything else, they weren't bare or anything.

 

[trj360]

Red arrows mark the wires coming from the box that used to go to the trailer plug. I only put 2 arrows to show that they are the same wires. The green arrow points to the wires that go from the tail lights to the junction box. (Ignore the green part of the first red arrow)

Edit: the wires I pointed to in red are the ones I chopped off just after this picture.

 

[edman1000]

Interesting read... Today, coming into work, lost all dash lights. Albeit, this is in my '96 ranger... well used ranger I might add... When I got out at the Post office, I noticed no taillights or running lights (parking lights). It was early enough that there wasn't many cars on the road, so I made the mad dash to work. Got into the parking lot at work, Pulled the #3 15amp fuse for the running lights/dash lights... blown. Didnt have a 15 so I popped in a 5amp to see what it'd do... Popped right away. Had a 30amp, put that in and turned them on, they came on but were dim. Only left them on for a few seconds, pulled the fuse back out... let the wild goose chase begin!

 

[venim74]

just wanted to say thanks so very much...was a good read and hopefully I will be able to drive at night again......i have been having same issue and so am NOT a mechanic in anyway...tho it doesn't stop me from gettin dirty...found trailer wires rubbed bare ...UGH but without this I would have never figured this out