HELP! 99 4runner(3.4): rear parking and instrument panel light doesn't work
 

Hi, I have a 99 4runner sr5 3.4.
I have searched threads regarding this issue online but I want to ask something that's not asked before. I was pulled over for this last night and I need help ASAP.
As you can tell from the title, my rear parking lights and instrument cluster lights don't work. Both Headlights and both blinkers(front and rear) work nicely. The tail light relay and fuses relating to tail lights are all checked good. What I did that could have caused this is, I went to a junk yard and replaced a panel(the panel that has an instrument cluster dimmer switch and fuse cover: located right below the steering wheel) with switches inserted on to it, meaning I discarded my panel with a good working switch.
Before this, everything worked fine. I suspect that a bad instrument cluster dimmer switch that came with the panel is causing all this problem. But I don't understand how a bad instrumental cluster dimmer switch can cause the parking light to go out..Is there any connection between them?

BTW, I have power going to the instrument dimmer switch pig tail but the switch itself doesn't show any resistance, helping me assure that the switch itself is bad, causing the instrument light to not lit up but parking lights? I have no clue.. Please help. Thank you.

All on the same circuit

The fact that the rheostat is open

When you swapped your clusters are they both from the same year ??

Just where did it come from protected from the weather??

Connectors can be corroded that you can`t see with out looking through magnified a lens Yet the check fine with the meter probes but when connected don`t work

Quite possible you have a bent pin

One of the jumpers in the gray plug might not be installed

How you could do work on circuits that effect lighting and not check every thing worked

The instrumental cluster is not swapped. The only thing changed is the the guage trim. It was not protected from the weather but it shouldn't have been wet or anything.. The part number for that is KM603424.
That trim is the only things changed, making the difference. The dimmer switch, the rheostat, is inserted into the trim itself so that being different and faulty can be the cause of the gauge light not working. I understand it is in the same circuit but how can that be related to the tail light problem? One faulty switch can affect the rest of the system?

The blue circled part is rheostat for the instrument cluster. How could the switch being bad affect the tail light!? Is it because if the switch is bad, the ground is not working properly?! I'm such a noob in terms of schematics so please help me!! thank you

https://cimg0.ibsrv.net/gimg/www.yot...3d6c229034.jpg

Well, you are correct that the rheostat should not effect the taillights. So. IMHO, the correct thing to do here is troubleshoot the taillight issue on its own, first, and see where that gets you.

How about your front marker lights (the ones next to the headlights) and the license plate lights?

Never rule out bad bulbs, ever. Swap in known good ones, test with a battery, do whatever you have to do to make sure they are good.

Then, determine if you have a ground problem or a 12V+ issue at the bulb. I like to run a wire direct to the battery, and first jump positive to the hot terminal, and then negative to the ground terminal, making sure that one of them causes the bulb to come on. That done, you can start to trace the failed circuit back to the fault.

http://tacoma.site40.net/4Runner_96-...emci/024tl.pdf