I have an '89 GL-10 Turbo wagon. It's running fine, but has some electrical issues that I can't figure out.
Right now, several of the dashboard idiot lights glow whenever it's running. They're a tad brighter near idle, more faint when at speed, but always on to some degree.
The power locks only work occasionally, but that pre-dates this problem. I also had to bypass the ignition switch starter position and install a pushbutton starter, but that was 20K miles ago. Just saying that the car has never had the healthiest electrical system (owned it from new, so it's not from anything that was *done* to it).
The voltage gauge shows odd readings...high (15-6V) sometimes, occasionally a little low (usually where there are high electrical loads, so this might not be *that* unusual). When the voltage is high, I can drag it back down by turning on the rear defroster grid. Later in the same trip, I can usually switch that accessory off and all's well again. This particular behavior seems slightly temperature-dependent -- the high-voltage problem seems more frequent on hot days.
The battery is recent. The alternator isn't particularly new or old. I've checked for bad grounds in obvious locations around the battery, but they look good and solid.
What should test next? What should I be looking for? Any ideas?
Like I said, it runs Ok, but it makes me very nervous. I also don't like to play voltage regulator (by switching on/off the rear defroster) when the voltage kicks up for no reason.
Thanks!
Scott