Rear doors do not trigger dome lights

[mrsleeve]

Ok YES I have spent about 2 hours searching. It should be a quick answer to a simple question. This is not my 1st go round with electrical gremlins and I have the issue narrowed down, as laid out below.

My rear doors and hatch do NOT trigger either the dome light, nor the door ajar warning light in the cluster (beent this way since I bought it and finally getting around to fixing it). My door jamb switches seem to be functioning properly as I get continuity between the wire terminal at the switch and the metal plate that bolts the the thing to the truck (I have not checked the rear hatch switch in a similar manner yet). I get good signal when the switch is in the door open position and none in the door closed position. I also have NO continuity between the ground wire on either rear door switch when connected directly across the back seat to each other.
.

This tells me that the grounding point for them is either bad, or I have a broken wire after the splice. I am also assuming that the rear hatch switch also grounded to this point and and ties into this circuit (given they all run to the same ajar light on the dash from the rear of the rig)

So this leads me to my question, so I don't have go and tear apart the entire interior of my 80. Where might one commence to look for the grounding point, and splice points for the dome lights, rear doors and hatch trigger switch's ????


Thanks a bunch guys
RJ

 

[SmokingRocks]

Have your wiggled the door sensor when the door is open? Both of my 93's exhibit this behavior. I can get the lights to come on when I wiggle the sensor the right way.

Leads me to believe the sensor has corroded / is worn out / or that the contacts inside of it are dirty.

 

[mrsleeve]

Yes I have, they have great continuity from the wire connection on the switch to the base plate individually. ( I do know how to run a muliti meter ) But not across the circuit in the body harness. Which would explain why all 3 rear doors exhibit the same behavior

 

[artech]

I used to have a problem in my 95 where the overhead light worked from the back doors but would not come on when the front doors were opened, then suddenly it reversed itself and now they work from the front doors and don't come on when the rear doors are opened. Pretty bizarre!

I hope you get some resolution, 'cause I'll be digging into the same spot wherever it is...

 

[gsdog2]

My 95 did the same thing with the front dome light. Took it out to inspect it, discovered nothing was really user serviceable so put it back in and know it works fine ever since. I'm guessing it was the connector being unplugged and plugged back in. I have no idea.

 

[landcrshr]

What year is your Cruiser? The dome light circuit changed in '95.

So this leads me to my question, so I don't have go and tear apart the entire interior of my 80. Where might one commence to look for the grounding point, and splice points for the dome lights, rear doors and hatch trigger switch's ????

The "grounding points" are the door switches themselves. The common wire for the switches can be found behind the left kick panel. IIRC, it's the 6-pin plug exiting the A-pillar.

 

[Hornd]

Exact Same Issue Here.
Also Rear Door Lights in Doors very dim (bad ground?)
My Rear Defroster is also not working, but has 12V at Defroster (no ground then) and switch lights up.
I think something in Front LH kick panel got wet.

 

[gofast]

Mine was the same until I sandpapered the bulb holder in the light itself. I guess it had oxidized. Still "winks" once in a while

 

[Darne]

Try the splice point in this thread. Worked for me.
Rear Dome Light Comes On on LR Door, Not RR Door....

Dan

 

[mrsleeve]

Ok little more info, mine is a 97. My rear switch/light housing was bit iffy, so I took some time and took it all apart, ( A die grinder and a couple of soldering irons and an hour latter) my rear switch is all back together, with a much tighter action and now bench tests fine on both circuits. Put in in the truck and the only position that works is the "ON" position.... But that is only supposed to come on with the rear hatch, so its not helping me though its nice to know it should work when I get this resolved and does work better in the on position far better than before.

So there is no common grounding point other than the switches base plate and bolt themselves, this makes sense, so now I need to hunt down the splice for the common ground wire for all 3 rear doors. and look for a break between there and the dome light relay.... Also my rear defroster is weak, lights up at the switch but very weak heating and non existent when very cold .

 

[427060]

You may get continuity, but how much? In my 80, the door jamb switches will provide continuity but they're worn out to the point where they won't make full contact. A voltage drop test while moving the switches might be a better way of testing them.

 

[flagstaff]

Is this your problem?
Your symptoms sound the same as mine. Thought I would try this.

 

[mrsleeve]

OK bit of an update since I have been so busy the last few days had a couple of mins to mess with this again. My front 2 switches work fine so I tested both my rear door switches by popping both put of the door jambs, running a jumper form the wire at the bottom of the switches, and grounding the plate of the rear switch to the door striker via jumper wire this allows the rear switch alternate access to the know good circuit. .....

When the rear switch was depressed (door closed position) as expected when the front switch was manipulate the light came on. Had the same results when the front door switch was held in the door closed position and the rear switch was manipulated by hand with no visible fluctuations in brightness when the rear switches were in the door open position.....


So this brings me right back to square one with this issue and my original post, and I suspect the broken wire is somewhere in the lower B pillar or in the driver kick panel now...... Anyone know where the splice is for this rear doors ground circuit....

 

[flagstaff]

Have you checked the connector? Might be worth a try. I replaced my switch and it works well. The tab in the video above was broken so repairing the switch wan't much of an option. The new switch was $15. Not too bad.

The connector was behind the rear door (blue housing in bottom picture, not connected to the switch). Access is through the plastic panel next to the third row seat.
The wire is red with blue. Hope this helps.
One question for anyone who can answer, what is that big connector in the bottom picture for?

 

[96FZJ80]

my driver's side rear door does not trigger the dome light when open. However, when I play with the plunger a bit there is a definite sweet spot where the light comes on. I think I just need to clean up the contacts as shown in the video in this thread. Removed the bolt and pulled the assembly out of the hole in the jamb but there is no connector to disconnect so I can move the switch to the bench. Just checking if there's a trick I missed somewhere or if I just need to do this while it is still connected to the vehicle.

 

[96FZJ80]

Forgot the pics

 

[ThomasMore66]

I bought 4 replacement switches. When the light doesn’t work I just replace the switch. It’s really simple. Just don’t let the one wire fall back into the door frame.

 

[96FZJ80]

I bought 4 replacement switches. When the light doesn’t work I just replace the switch. It’s really simple. Just don’t let the one wire fall back into the door frame.

How do you disconnect the old switch? I tried pulling it out of the white plastic to the point I thought I might break something and it wouldn't budge.

 

[Tedward]

You disconnect the wire. The switch has like 8 inches of wire and a plug. The plug is inside. Might have to take the interior trim piece of to get to it, or it may pull out far enough to get to it. Flagstaff post has I pic if the little blue connector. It's not easy to get apart, gotta pry it apart and pull. There are other pics of this floating around here

 

[96FZJ80]

OK. So there's a connector in there somewhere. Couldn't get it out through the hole in the jamb. Might have to take some interior trim out to get to it. Thanks.