Weird interior electrical issue.

[CHRIS904]

Hello got a 98 bonneville with 38k miles. It has some quirks electrically. I have a weird issue were sometimes the cluster, radio, a.c goes totally dim. Today I noticed if you put the vehicle in park I could get them all back on and adjust brightness with twilight switch. Once I put back in drive all the lights went back out. Then heading home today everything works as normal. It's so strange. I did fix a water leak with the car. I noticed condensation inside the vehicle. It has been sitting for years so I'm sure that water probably has corroded ground wires etc. it was leaking from the trunk to rear passenger side back seat. Anyways any ideas were to start would be great. Thank you.

[harofreak00]

Probably a faulty photoelectric cell in the Twilight Sentinel system. It's located on the defroster grill.

[CHRIS904]

I'll have to see if you can even find these things anymore.

[harofreak00]

It should be an easy find at a salvage yard, but it will be difficult to find online.

[CHRIS904]

Did they use these in anything newer I can't even find a part number or anything. Salvage yards don't have these cars around here anymore.

[95naSTA]

I think that you only need to replace it if you need that functionality. If you have the dial on the headlight switch turned so it's off, it should operate without it.

[CHRIS904]

I think that you only need to replace it if you need that functionality. If you have the dial on the headlight switch turned so it's off, it should operate without it.

Is is off when you feel it click off all the way to the left? If so it's always been off and the interior still dims itself flickers on and off etc. I was thinking it was probably the switch or a bad ground.

[95naSTA]

It's been too long for me since I've used it but here's what I found:

92-94 the sentinel off is turning all the way clockwise (aka backwards of every other year)
95-99 Sentinel ring is turned counter clockwise to turn it off.

I would try cleaning up the ground bus bars. I would also measure the voltage at the alternator to see if it's surging.