IM sure its a short somewhere, but im not sure where to look or start to correct this problem. Also there are no pannel lights, so I have gotten a good sense of how fast I am driving w.o looking at speedometer at night.

I just bought it for $600 with it only having 110,000 miles. I knew the guy and he was going to sell it for $2000. So i got a sweet deal but I have to fix up some somethings like this and headlight/tailight lenses.


White 89 SSE

Are there any interior lights that come on when you turn the headlamps on? What happens to the VF displays on the stereo and A/C controls?

ya, all the lights come on in the interier when i turn the **** all the way up. When i turn my lights on, the display for the time/radio and the heater/AC screens turn off. There arent any panel lights when i turn my lights on. My screen that has the car status on it and my compus stay on though.

Right. Except for the dome and door lights, are there any red lights on the dash, climate control, radio, or gear shifter console that come on with the lights? Does turning on the headlamps have any effect on any other interior lights, except for the VF displays for the radio and A/C? Do the VF displays for the driver information and the compass get dimmer when you turn on the headlamps?

It appears that the dimmer rheostat is bad, or the power to or from it is shorted because when you activate the headlamps, it is having an effect on the VF displays. The symptoms you describe are similar to those of a rheostat turned all the way off.

Also double check to see that you don't have a blown 5A fuse in space 25, or any other blown fuses.

The only thing effected by turning on the lights are those displays i was talking about above. And ya, the compass and driver info do get dimmer. The Seatbelt sign stays on though. And i have no pannel lights that light up my speedometer/RPM/Gas display. Also no lights for my gear consol But thanks, ill check on that fuse and other fuses.

Where would i begin to look if its a short? Just test wires in random places in the car that lead to the displays?

Check the fuse for your interior / Instrument / I/P / Dimmer lights. If that checks ok, its a yellow wire that flows along from one device to the next. It comes out of the fuse block, and will them go from your headlight switch to Instrument Panel to Climate control Unit to Radio to power seat controls, etc..

Its basically just a signal wire, it doesn't actually carry the load to power all the lights. The is the wire I put a switch on, so that when My Parking and Fog lights are on during the day I can effectively turn off all the interior lights, and keep my Compass / Car + Drivers Info Center / and most important HUD bright during the day instead of going dim.

I'm not saying yours has a switch, but maybe a short. worth checking out.

Just a thought...

thanks a lot, ill try to check that wire. This is for an 89 Bonneville so i hope your setup is similar to mine.

What I would do after I check the fuses is

1. Pull the dimmer switch from the dashboard and check with a multimeter to see if there is power to it (test across the orange and black wires)

2. Check to see if there is varying power across the grey and black wires while you move the rheostat back and forth. To do this the switch will have to be connected.

If there no power to the switch, then you can work backwards thru the wire to the fuse. If there is no change in power while moving the rheostat back and forth, then the rheostat is probably toast.