Help! My electrical system has gone haywire.
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).