7 replies to this topic

[bobgrice]

new to me '97 855 with 100k on the clock. Great condition overall.

At night, I've been noticing that ALL lights (headlights, interior lights, etc) will slightly dim, then immediately return to full bright. No definite frequency, just every now and then.

I cannot seem to make it happen and it does not appear to be alternator load-related (revving engine does not change lighting one way or the other), A/C doesn't affect things, etc.

In other words, it seems to be a bad ground (although going over rough roads or bumps doesn't affect things at all - it will dim & brighten when you're sitting still) or, more likely, a bad headlight switch?

Any help would certainly be appreciated. Thanks in advance everyone!

[Bay13]

Tough one.

Start by cleaning all the grounding points you can Eyeball. Ensure your Serpintine belt isn't shinny and full of crack. Consider having the battery and the alternator load tested. Might be a dirty switch on the dimmer switch for the cluster lights.

[AJU]

Any luck resolving this issue? I have the exact same symptoms and the battery and alternator load tested fine.

[AJU]

Another related question: where are all the grounds located that I should clean? I already cleaned the battery terminals and this didn't resolve the problem. I know there is a ground wire in front of the battery. Where else should I look?

[AJU]

bump

[kenk]

wish i had more info about where the contacts are to clean, probably the battery, and any other grounds you can find.

Dielectric grease can really really help with contacts, you can get it at any Menards type store. Basically it protects and improves contact after you have cleaned them up.

Id recommend you use some kind of sandpaper or metal brush to really clean up the battery terminals just wiping them or brushing the crud off doesn't get them nearly as shiny as if you use some sandpaper. You can do the same with the contacts, pretty much if its a solid clean looking connection, it usually is electrically as well.

also replace your headlight bulbs, its a cheap thing and might help if one of them has a weird filament, they are a pretty high draw item..... and you can use the ones you pull as backups...

.... do you have an after-market radio that might be drawing more current than stock, and your only noticing the dim at night?

[AJU]

Thanks for your response. I used a wire brush terminal cleaner to clean the contacts, and I got them good and clean. I also removed the ground wires in front of the battery and cleaned then as well using the wire brush to get down to the bare metal. I didn't use any grease, but that shouldn't make any difference if the contacts are clean and tight. I don't have any aftermarket electronics and I can't relate the dimming to any accessories. I have only noticed this happening at night, and it seems to happen everytime I leave work in the evening. Turning on/off the heated seats, the radio, the rear defrost and the ac/heater blower do not change this at all. It's not related to the cooling fan, as it happens when the car is cold. I am going to clean the contacts to the IAC next and see if this helps, but I don't think that it would kick on and off in the cycle intervals that I am seeing the lights dim in.
Anyone know what else is on the circuit that the headlights and dash lights are on? My lighter socket has stopped working and I have been getting a code (p0410) for the SAS system. Maybe the air pump is shorting everytime it tries to run, but again, I don't think it would cycle like this. Is the air pump on a fuse that I can pull to rule it out?
Anyone?

[AJU]

bump