[EmDeeAitch]

My 2000 has been giving me some electrical issues over the past couple of months.

Here's a list in the order they started.

1. The rear window only intermittently works when pressing the up/down button up front
2. Mirror defrosters only stay on for 5-10 seconds before turning off
3. The ring light around the key turns on and off intermittently when the vehicle is in motion.
4. Lastly, and most annoyingly, the doors won't stay locked when driving. I press the armrest lock button, and then anywhere from 1-30 seconds after, all doors unlock. This only happens when the car is running... I can lock it just fine when the key is out of the ignition, with either the door key cylinder or the armrest lock button.

From reading older threads, it sounds like the rear window and mirror defroster are somehow connected, so these might not be related to the key light/door lock issue.

The unlocking issue only seems to happen when it's raining outside, which makes me think there might be a leak somewhere that is getting into a control box that controls all these functions. But I'm not sure where that controller would be.

Any input is appreciated. This has got me stumped.

[Bumbo]

Bit of a guess but I would take a quick peak at the wiring harness around the parking brake area... make sure no wires are damaged from abrasion or anything.

Sounds odd but that happened to my Silverado and had a bunch of problems like you mentioned. Things like window rolling down randomly when driving. All went away once I fixed the wires with butt connectors and shrink.

[spartacus]

Take a peak at the wiring loom that goes into the tail gate on top. Those wires get fatigued and break causing myriad of issues.

Rear Hatch Wiring Fix

[Kanoe]

The interior fuse panel/relay module is in front of the drivers left knee. It is mounted so that it can get wet if you are having leaking from the left side of the windshield. When it gets wet strange things happen. Somehow drips from above get on it.

I had a funny issue with this when camped in cold wet snowy/rainy conditions for a few days, sleeping in the 4runner. Condensation from the windshield got it wet. I thought I would fabricate a splash shield but in 8+ years of ownership thats the only time it happened so I never bothered.

This may be a place to look.