Door courtesy light switch electrical issue

[levipigg]

I had a similar issue recently, the passenger rear door switch wasn’t triggering any of the lights so I figured it was the switch, replaced it and that didn’t do anything, so I checked for +12V and there was nothing. I then started checking for continuity by putting one end of the multimeter by the switch and probing the wire (red with blue stripe in my 95) until it read open. I then found out that the break was somewhere behind the B pillar, so I opened up the wire loom and there it was. There was some sort of butt connector wrapped in blue tape (factory I think, there was another one just like it, circled in orange below) where the wire coming from the front split into two wires (one going up the B pillar and one going back to the C pillar). All that was left inside the tape was a piece of metal the size of a grain of rice (it was green like an old penny). The wires looked like they had been freshly cut because there was nothing left.

Here’s a photo of all three of the wires (you can actually see the green on the top left wire before I cleaned it up).

I didn’t get too good of pics but here it is all finished up (after soldering and heat shrinking connection).

Now I need to figure out if something spilled or if it leaks when it rains or something.

 

[Tedward]

Just went through this same thing.
Those are factory wire splices and in the EWD as such.

That wire bundle lays in a 'trough' and when I most recently opened that area it was FULL of water. The wire bundle was half submerged and water dripped out of the loom for day or two.
In my case it was water ingress was from 2 places.

1: The sunroof pan had been overfilling and exceeding the amount of water the drains could deal with. This water came down the A-pillar, passenger side, behind the trim and the kick panel. This water pooled up under the plastic backed carpet unnoticed and went to the low area. The wire trough. Had been happening for some time. Pulled the carpet from the front passenger area the jute was soaked. The floor had minor surface rust.

2: The a/c drain was not installed, by me, correctly. The end of the tube could be seen inside the firewall, behind a heat sheild, and water dripped on the ground like it should. However, it was not completely through the grommet, the grommet was not seated just right. So some of the a/c water dripped on the ground but some ran down the inside of the firewall and pooled in the low spot again.

It's all better now.

So, for you, I would guess it's one of those two and my money is on the sunroof. I did the old 'bicycle inner tube fix' and all is well.

Oh and the courtesy lights are back functioning!

 

[levipigg]

Just went through this same thing.
Those are factory wire splices and in the EWD as such.

That wire bundle lays in a 'trough' and when I most recently opened that area it was FULL of water. The wire bundle was half submerged and water dripped out of the loom for day or two.
In my case it was water ingress was from 2 places.

1: The sunroof pan had been overfilling and exceeding the amount of water the drains could deal with. This water came down the A-pillar, passenger side, behind the trim and the kick panel. This water pooled up under the plastic backed carpet unnoticed and went to the low area. The wire trough. Had been happening for some time. Pulled the carpet from the front passenger area the jute was soaked. The floor had minor surface rust.

2: The a/c drain was not installed, by me, correctly. The end of the tube could be seen inside the firewall, behind a heat sheild, and water dripped on the ground like it should. However, it was not completely through the grommet, the grommet was not seated just right. So some of the a/c water dripped on the ground but some ran down the inside of the firewall and pooled in the low spot again.

It's all better now.

So, for you, I would guess it's one of those two and my money is on the sunroof. I did the old 'bicycle inner tube fix' and all is well.

Oh and the courtesy lights are back functioning!

Wow, I’ll have to do that before winter. I forgot to mention it but mine work now too! No more opening the front door just to light up the back.

 

[thelal]

good find

 

[Bsteimel]

I had a similar issue recently, the passenger rear door switch wasn’t triggering any of the lights so I figured it was the switch, replaced it and that didn’t do anything, so I checked for +12V and there was nothing. I then started checking for continuity by putting one end of the multimeter by the switch and probing the wire (red with blue stripe in my 95) until it read open. I then found out that the break was somewhere behind the B pillar, so I opened up the wire loom and there it was. There was some sort of butt connector wrapped in blue tape (factory I think, there was another one just like it, circled in orange below) where the wire coming from the front split into two wires (one going up the B pillar and one going back to the C pillar). All that was left inside the tape was a piece of metal the size of a grain of rice (it was green like an old penny). The wires looked like they had been freshly cut because there was nothing left.

Here’s a photo of all three of the wires (you can actually see the green on the top left wire before I cleaned it up).


I didn’t get too good of pics but here it is all finished up (after soldering and heat shrinking connection).

Now I need to figure out if something spilled or if it leaks when it rains or something.

Levipigg - I had the exact same issue and the exact same splice had come apart.

My passenger rear door would not turn on the dome light/door light or light up the dash icon when it was open. I hacked into the same wiring harness and the wire coming from the door courtesy switch on the door connects in the 2 wires, 1 going to the light and the other going to the main harness. The wires were originally soldered then wrapped in that blue electrical tape, the solder had disintegrated. I also noticed that the connection point was really tight, there was absolutely no slack in that connection. I added a a few inches of wire, spliced it back together and shrink wrapped it.

I have included the wiring diagram below and highlighted the connection point for future searchers. I wanted to fix it because it's where my kid sits and its annoying to get her buckled without any lights and I wanted to know if that door wasn't closed all the way. Plus its nice just fixing 1 more thing that has gone wrong.

 

[truthdetector]

Wow, what a time-saver this forum can be.

Same symptoms, shot the parts cannon at the courtesy switch, which didn’t work, so I searched MUD and found this thread.

Posting not just to thank those who already figured this out, but to add that my splice was completely corroded and afaik, there is no history of water ingress on that side of my rig.

 

[Malleus]

Levipigg - I had the exact same issue and the exact same splice had come apart.

My passenger rear door would not turn on the dome light/door light or light up the dash icon when it was open. I hacked into the same wiring harness and the wire coming from the door courtesy switch on the door connects in the 2 wires, 1 going to the light and the other going to the main harness. The wires were originally soldered then wrapped in that blue electrical tape, the solder had disintegrated. I also noticed that the connection point was really tight, there was absolutely no slack in that connection. I added a a few inches of wire, spliced it back together and shrink wrapped it.

I have included the wiring diagram below and highlighted the connection point for future searchers. I wanted to fix it because it's where my kid sits and its annoying to get her buckled without any lights and I wanted to know if that door wasn't closed all the way. Plus its nice just fixing 1 more thing that has gone wrong.

View attachment 2904025

View attachment 2904026

View attachment 2904027

That's some soild work right there.

 

[jcardona1]

Mine are all jacked up too, not sure what's causing it.

Wow this was 10yrs ago. And my lights still aren't working. Maybe this broken wire was the culprit all along!

 

[jcardona1]

You guys rock. A decade later, all 4 of my courtesy lights are working for the first time!