My wife and I have a 1986 Pontiac Bonneville Brougham, that we have owned for several years. It currently has around 67k miles, and up until this past weekend, has been an excellent car!

Last Friday evening, we went to Wal-Mart, and when preparing to leave, I noticed that all of the presets on my radio were out. I reset everything, and we went home without issue.

We spent the day Saturday running all over Tulsa and didn't notice any problems. On Saturday night however, as my wife jumps in the car to run to the local video store, she discovers the radio presets are gone again, and there are no headlights. I decide that it is dark outside, and I will look into this on Sunday.

On Sunday, I find the following results:

Working systems include turn signals, brake lights, reverse lights, lighter, dome light (activated by doors and light switch), and ignition system.

Failing systems include, dash lights, charging system, dash clock, parking lights, head lights and as an oddity, if I turn the headlight switch on, the dome light comes on instead. Also, the dash panel dimmer seems to have the dimming/brightening effect on the dome light.

I have checked the fuses. I have taken the alternator to AutoZone and they say it is fine...I replaced the negative battery cable because it had a little corrosion on it, and I have scowered the car for any loose grounds that I can find (there were a few and I tightened them). My problem still exists, and I have run out of ideas.

Has anyone else ever seen anything like this, or do you have any ideas as to where one might look for the issue?

Also, as long as the battery is charged, the vehicle will start and run normally (with the exception of the failing systems listed above).

On the later models I know there are tons of ground and power related problems caused by corrosion at both ends of all battery cables. You may want to pull all the ends and clean them up.

Beyond that the car is too different from mine for me to help much. The vets should be on this pretty quick.

I would bust out a chiltons and check out to find where all your fusable links are. I had a similar problem on my first truck. It was a 1980. The fusible link crapped out and all I had were running lights, no dsah or head lights and the radio was either not working right or not at all. I'd say that would be your best bet.

sounds like most of the problems are centered around a bad headlight ****?

Thanks all. I am still tracking this problem. I have check and cleaned the battery connections...I have replaced the light switch...I am in the process of tracing the fuseable links, but alas, this issue still haunts me.

Thanks for the pointers thus far...if anyone has more ideas, please enlighten me.