Interior light gremlins (1 Viewer)

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Jul 21, 2017
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Palo Alto, CA
My 93 FZJ has several issues that are pointing me toward the dome interior light circuit (attached image).
1. High dark current draw led to battery dying (will measure again with fresh battery)
2. Flickering dome lights

I followed the path of others by refurbishing the door pin switches, and this debugging process has led me to a few questions:
Q1: Where are the three door switched lights (highlighted yellow) in the wiring diagram? I know where two of them are - one right above the middle seat of the middle row and the other in between the jump seats. Where's the third one?
Q2: Where is the diode for interior light (highlighted magenta)? I'm guessing my door ajar light in the instrument cluster is dead but probing this diode is would help me figure it out.
Q3: The back door latch (highlighted green in image) is reading 0-10Ω between the two contacts whether or not the latch is open or closed. Sprayed the inside with some deoxit and no change. I'm pretty sure I need a new one since I can't seem to open it for rebuilding. Anyone know the part number? I may drill out the rivets and take mine apart once I get a new one. Otherwise I may just leave it detached.
Q4: I have a hunch that this is related to the TVSS alarm system. I would really like to get keyless entry to work. Does anybody have the EWD for 00398-00921?

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Joined
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east coast Canada
 
 
 
Unless you have the baggage compartment light installed the rear hatch switch is doing nothing. The NA models do not have the baggage light installed. Lots of people like me have installed one, typically removed from another rig from the front or middle position.

The diode would be part of the harness, inline, not plugged in like a relay.

Back door switch is probably not your problem.

Search here for baggage light or third row dome light.
 
Joined
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Thanks for clearing that up, @voodu3. I realized that there are a couple versions of the wiring diagram in the same service manual; after seeing your image I found the diagrams that show the luggage light and D9.

@fjbj40 The path with diode D9 connects to the rear hatch switch, and is in parallel with the baggage light. Wouldn't it mean that the rear hatch still serves as a switch to ground regardless of whether or not there is a baggage light?
 

voodu3

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I would think it’s connected. I think the only part that’s not there is the cargo light. My guess is it’s the switch Or the wiring in the rear hatch. 27 years of slamming shut would take its toll.
 
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east coast Canada
 
 
 
When I installed my baggage light, 2 months ago, some of the wires that go from the body to the rear hatch through the rubber boot were cracked from work hardening of the door being open and closed since 1993. There was also corrosion in that harness connectors at that area. Easy to access on the left hand rear pillar area.

If you have the wiring manual it will tell you exactly where that diode is also. If you don't let me know and I will check in my manual.

I also had some dome light issues, it ended up being both rear door switches, more so the lh side but I decided to change both. My dome lights would sometimes stay on or flicker when you pushed on the door ever so lightly. A hard wind could probably have made it flicker.

pics here Rear hatch light switch
 
Last edited:
Joined
Dec 8, 2006
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9,383
Location
New Jersey
 
 
My 93 FZJ has several issues that are pointing me toward the dome interior light circuit (attached image).
1. High dark current draw led to battery dying (will measure again with fresh battery)
So did you ever verify that your parasitic draw is in fact the dome circuit, or are you assuming it is?
Can you quantify "High dark current draw"? Did you measure this with a ammeter?
 
Joined
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Palo Alto, CA
Worked on it more today with a fresh battery. The battery is sourcing 112 mA with the dome fuse plugged in, 12 mA without.

This is after sorting out a bad door pin switch and messing around with the rear wiper motor electronics (unsure if related). See attached for more details; order of events reads top down.

Weird that the current draw went up at the end of the day. The lights flicking on during a drive signals something to me too; may be like what fjbj40 is seeing when pushing on the doors. The dome light sockets don't pull dark current when stationary, but the dark current remains high. Any thoughts on what to probe next?

For fun, I measured the old battery at 2.4V! with a dark current drain of 16 mA, 2.5 mA without the dome fuse.

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Last edited:
Joined
Dec 8, 2006
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New Jersey
 
 
The only possibilities for quiescent current draw is the light retaining relay and the diodes.
The light retaining relay can be unplugged for testing.
The diodes are actually plugged into connectors that appear to be hanging with no mate.
 
Joined
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I spent another 8 hours looking at this and I'm pretty sure I found the problem. The culprit ended up being a door pin switch that I broke when I took it apart for cleaning. I should have narrowed it earlier when I noticed the lights flickering whenever going over bumps.

Turns out the door ajar light was burnt out and the keyless entry for TVSS works now!
@voodu3 Hope your debug is going well. Other things that may be useful to check: ignition light relay box, any aftermarket radio components, any wiring in rear panel where the jack resides (BR1, BS1, BS2, mine was rusty probably due to leak)

Thanks to all for help and suggestions!
 

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