MoJ
Moderator
1. If you’ve had a sunroof leak or your dome light doesn’t work when opening the drivers door, you should inspect the alarm tee connector that is under the drivers sill plate cover. It’s a red wire with black tracer and silver dashes. The connector had allowed water contact from the sunroof leak, causing a 1/4” section of the wire to corrode. The connector itself didn’t look bad but when I removed it the wire broke. The copper strands near the connector had turned to green dust. Using the same color wire from the removed alarm harness I soldered in a new section and covered with heat shrink. Shazam, working domelight.
2. While you have the drivers kick plate removed check the ground wires that attach to the body with a 10mm bolt. Pic below. Mine were very loose.
3. The install job on the Toyota alarm was horrible. I suspect someone had also installed an aftermarket alarm along the way and further hacked into the alarm harness. Glad to have it out of there.
Cross section of wire with corrosion: