I have a very strange wiring/light problem

[jlee]

My MR2 has courtesy lights in the door panels - they're supposed to come on when a door is opened, and I think they're supposed to slowly dim out when the doors are shut.

This is what I have now:

If I open the passenger side door, the passenger side light comes on.
If I open the driver side door, the passenger side light comes on.

When I close the passenger side door (if the driver door is already shut), the passenger side light shuts off and the driver side light comes on for a few seconds, then shuts off.
When I close the driver's side door (if the passenger door is already shut), the passenger side light shuts off and the driver side light comes on for a few seconds, then shuts off.

I've been told to check the bulbs (doesn't make sense, as they both work, but they're both new anyway) and that the switches may be bad. New door jamb switches are $18.60/ea from Toyota. I'll replace them both if necessary, but I don't really see how that could be the problem. Thoughts?

 

[exdeath]

Is there some kind of logic module for that? Usually fancy lighting schemes with dimming, timers, auto power windows when you push all the way, etc, have a small logic board in the driver side door switch panel with either a tiny chip or some transistors and capacitors, etc.

 

[jlee]

Hmm, I have no idea. Good call, I'll look into that.

 

[SpatiallyAware]

Yeah doesn't sound like something that's even possible with a faulty switch, bulb, etc.. Unless the logic board relies on the load from the bulb


If it were me, I'd do the cheap and easy first - replace the bulbs, clean the switches.. Then look at the wiring diagrams and see where they terminate


Isn't that the era that had tons of cold solder issues?

 

[jlee]

The bulbs are new LEDs - I had the same problem with the old bulbs, too. I should be able to check the switches easily enough, though.

Not sure on the cold solder issues..fortunately it's not a critical issue so I can fix it whenever, but it is annoying nonetheless.

 

[exdeath]

The driver side panel is normally the brain for the lighting, power windows, door chime and dash "ajar" light, etc. The passenger side is just a remote switch run, as are the jamb switches, etc, they should all bundle together to a connector that plugs into a box in the driver side door or somewhere in the dash. The normal behavior (timed dimming, etc) can't be implemented with just wiring, it requires some minimal electronics.

Also the problem as you describe is consistent right? Meaning its likely a bad capacitor, transistor, etc and not just a intermittent connection problem. My guess anyway, do you have a body/interior wiring manual?

 

[jlee]

The part that really confuses me is everything works...but it's split between the doors. I.e. on-when-open works on one door, but not the other...and auto dimming/timer works on the other door.

WTF.

 

[punjabiplaya]

bust out the dmm and see if there's a difference at the bulb/socket between when you open either door. Then you can narrow down where the signal is getting fubared and move on to the door panels/switches.

 

[exdeath]

http://stephenmason.com/cars/mr2doorwire.html

 

[EightySix Four]

http://stephenmason.com/cars/mr2doorwire.html

I hate to say it JLee, but I'd probably whip out the tech book and see if you can trace the wires from start to finish. Something, somewhere, is crossed.

 

[punjabiplaya]

I hate to say it JLee, but I'd probably whip out the tech book and see if you can trace the wires from start to finish. Something, somewhere, is crossed.

why i was suggesting a meter or even a scope if you've got one to save some time, but ultimately you might just have to trace

 

[DominionSeraph]

You probably have an IC setup to trigger driver's side dimmer when the passenger side light switches off, and to trigger passenger's side dimmer when the driver's side light goes out. So a single fault in triggering the driver's side light on kills the dim on the passenger side (because it never gets the clock that the driver's side went from high to low, because it never went high), while the passenger side is doing what it's supposed to and triggering the driver's side dim.