Toyota Repair Problems? Ask a Mechanic for Answers ASAP
Does the dome lamp stay on with all doors closed? Any warnings on instrument panel indicating a door is open?
Thank you for that information - usually, we see bad door switches as the main cause, but of course, the dome light does stay on. Since this not the case with your truck, we need to go deeper in the circuit to find the load responsible for the draw; that would be the integration relay in the Junction Box located in the lower left finish panel under the dash (see attached graphic). The circuit is constantly powered and gets ground whenever the lamps are manually turned on or the door switches are closed.
Testing these circuits will require you to use a voltmeter. Would you be able to do that, plus follow the current path on a diagram that I would upload?
Here is that graphic.
As luck would have it, how the windows are powered has no bearing on our issue.
Back to our integration relay (which is actually the whole printed circuit board), get in the truck and, with all doors closed and all interior lamps off and set to open with doors, check that there is no ground at the terminals I've highlighted with a Blue/green square on the attached diagram. If there is no ground, but the draw it's still there, then the Integration Relay needs to be replaced - hang on to your hat; that thing sells new for close to $300! (click here to see example)
Please let me know how you make out.
Looks like we're back at what I had posted previously "If there is no ground, but the draw it's still there, then the Integration Relay needs to be replaced". Used units are still available for under $100 - click here to go to sample online vendor's website.
Please let me know if you have any other questions or concerns.
On your original post, you stated "the draw goes down to zero when the dome fuse is out", so how can you still have a draw when you have not only the dome light fuse out but the whole fuse box/integration relay assembly unplugged?
I'm sorry if I didn't explain it better - the integration relay is part of the junction box and cannot be disconnected or removed separately from it. In other words, you would have to disconnect the entire junction box to disconnect the integration relay. Since the junction box includes the dome light fuse, disconnecting it would interrupt power to that fuse.