Rear lighting issues...

[JeffK]

Last winter I upgraded the booster and master cylinder to ones from a '99 WJ. Had some issues bleeding the system, but after bleeding the proportioning valve I got all the air out of the system. Yesterday I cranked it up and the booster was hissing. Crap. So I pulled everything off.

 

Went to the parts store and found that a WJ booster cost more than both a 95-96 XJ booster and new master cylinder. :fs1: So I bought the 95-96 Booster/MC.

 

I got replaced everything and bleed it out. I realized that I didn't have enough brake fluid so I headed back to the parts house for some more. :fs1: Bled out the system and finally good to go.

 

I turned to the brake light switch. I modified a newer model brake light bracket, installed a generic Painless brake light switch and depressed the pedal. Nothing. Jumpered the brake light wires and still nothing. Tried the turn signals. Nothing there either.

 

First I checked the bulbs or that was plan. Seems my son came by and borrowed every torx bit I own. Back to the parts store. I did pick up some bulbs while I was there, but after removing the housings I found the bulbs were new. The front lights and the dash lights/indicators work normally. The only thing I have in the back are the running lights (both top and bottom). The wires for the signal/brake lights do not have power coming to them.

 

My MJ is a 4.0/5spd and I had to replace the fuse block last summer due to a leaking slave cylinder. I also repaired the front signals and running lights. There are no other electrical issues at all.

 

What I've checked/done today...

 

1. Replaced the bulbs

2. Checked the fuse, Circuit has power on either side of the fuse.

3. Redid the ground at the LR housing

4. Remove the rigged up trailer harness and repaired the wires.

5. Checked the connector behind the LR tire, no corrosion or damage, looks new inside.

 

After cleaning the ground at the LR housing the running lights will dim slightly when the turn signals are turned on.

 

Is it another ground I'm missing? I worked through lighting problems on both my kids XJs, but this has me stumped. I'm out of ideas, any suggestions will be greatly appreciated.

[mfpdm]

Did they work prior to the swap. Not that it would have anything to do with it just trying to see if they ever worked. You should have 12V on one side of the brake switch because it's always hot. here's the diagram for the lights.

 

 

As you can see there are four separate connectors from the turn signal switch to the rear lamps. If you have a 12V at the brake switch going in, then you should have 12V going out and then at every connector. May have a broke wire in there somewhere or your turn signal switch may have bad contacts in it. Since you say the front signals work, I'm thinking a broke wire but electrical gremlins are always tricky. Hope this helps.

 

:cheers:

[JeffK]

The only thing that did not work when I replaced the fuse box was the reverse lights which is why I was so frustrated. I did yank the interior and all of the suspension and axles afterward, so like you I thought I had a broken wire somewhere. I figured the easiest way to pin point the break was to start at the front and work back. referred to your diagram and double checked for power at the brake light switch (pink wire) Good there. The next logical spot to check seemed to be the connector for the turn signal switch on the column (I did replace the column after the Fuse box). I'm all set to check it out and notice that one side of the connector is slightly cocked on one side. I pushed them together and hear a slight click. Bingo I have now have signals and brake lights.

 

The connection was probably never completely seated and with me working under the dash I managed to pull it apart just enough to break the contacts. :doh: Time spent on this yesterday-3.5 hrs+. Time spent today-less than 10 mins. I guess cooler heads do prevail.

 

I appreciate the input, it pointed me in the right direction. BTW great diagram, I'm gonna save that one.

[mfpdm]

Glad the diagram helped. :thumbsup:

 

In the Navy, I've experienced more than I care to admit, many hours trouble shooting something to only come back the next day and find it was a switch out of position. :doh:

 

:cheers: