Dreamcasti

So I bought a cheap LS400. It’s a 1996, but it has some electrical issues. I did the obvious, checking all the fuses, to no avail. So far it’s doing this. Not sure if there’s any known fix for this. I also have a known good 1998 LS400 if it helps.

No radio

No dome lights/trunk light/door lights

Door locks only work with key turned

Key fob doesn’t work

No clock

Dreamcasti

I’m also noticing a new alternator but it’s not charging so the battery dies. Very odd

BNastee

did you also check the row of big amperage fuses?

Yamae

These 3 problems must be related to the MPX body computer located under the dash near the steering shaft. Sometimes door computers are related though.

I worry that the 120A ALT fuse is open.

Dreamcasti

I ordered a new 120A fuse, I'll report what happens when I replace it. I have the box out of the car ready for the new one

Yamae

You mean the ALT 120A fuse was open?
Didn't you or someone hook the jumper cable up backwards?

The backwards connection kills not only the alternator fuse but also other polarity sensitive circuit's fuses. Sometimes it damages electronics circuits as is warned here saying "Hooking the jumper cables up backwards can create disastrous results⁠."

Even if not backwards, the old style jumper cable often cause problems explained here due to the surge voltage and we'd better to use a jumper cable with surge suppress devices.

FATBOY46

I just did a door lock problem on a 2012 ES350. Dealer replaced the control panel on driver door.- $1200 worked a few days. Then replaced a door lock regulator $800- that lasted a few days then they decided it was the Body Control Module $1700- Now everything works expect my wallet.