1995 Ls400 - Jump Started, Then Dash Lights Out!

David Culberson · January 1, 2012

Okay, this is a weird one. This is *not* the typical 1st gen dash light problem so it's really hard to search on. I had my alternator go out recently. I replaced that, then once it got cold my battery bit the dust. I think the battery was stressed from having been run down to flat too many times. I made the mistake of driving somewhere even after noticing that the car was a bit slow to crank over. I found a good samaritan to give me a jump, and I was having some trouble getting the car to have enough juice to turn the starter. I made the mistake of adjusting the jumper cables when the ignition cylinder was in the "run" position, and my dash lights (the gauge lights only, not the trouble lights, etc) burnt out. I replaced the battery, and so now the car starts and runs fine. EVERYTHING else works well, only the instrument (gauge) lights are still out. The fuse is okay, and the rheostat works to dim the climate control light and clock.

I was looking over the factory service manual and the diagnostic procedure. For my situation, where the tail lights work, it says the fuse or the wiring harness is bad. But in the block diagram it shows the "Body ECU" as being involved in illumination. Is it possible that I burned out the body ECU? Or is there a ballast somewhere, like in the cluster, that could be burnt out?

Does anyone have any idea what could be wrong / burnt out?

Thanks!!

steve2006 · January 2, 2012

Check the 80/100Amp fuse in the engine compartment fuse box, they sometime blow when jump starting, bit of a job to replace as the holder has to come out from underneath.

David Culberson · January 3, 2012

Do you mean the 80amp main and 120amp alternator fuses? They both look okay, and the car is running okay and charging the battery, so they seem to be working right. The only thing not working is the instrument illumination. The trouble lights work okay, and the gauges themselves work okay.

sao64 · March 8, 2014

H mate, I know this is an old post but did you ever fix this, I have the same problem. I'm very desperate to solve this , any help will very much appreciated