86 4runner electrical problem
 

UGHHH! what now? LOL1 having one of those murphy's Law days.
started with my highway car, we won't go there. LOL!
drove my 4runner to work today, about half way here the radio would start powering on and off. Then noticed the tach was bouncing all over the place.
I turned the headlights off and the radio shut off again and powered back on.
with the lights off the radio never shut off again, but the tach still bouncing.
turned the lights back on and the radio powered on and off again. and the tach jumped. and the radio would start powereing up and down again.
ever time the lights were turned on or off the radio would power cycle.
had the heater fan on also, but never had an issue with it.
when i got to work and shut the truck off and then started it again the radio power cycled and all my presets reset and it kicked out the CD.
the tach is now working fine and the radio is now working fine when turning the headlights on and off. this is just in the parking lot at work though. havn't tried driving it agan yet. and yes the radio is installed correctly! LOL!

Anyone have any idea's? would a failing alternator cause some weird electrcal issues like this?

thanks
Rick