As some have mentioned, the most likely problem is an intermittent voltage regulator
causing excessive battery voltage, i.e. >15 volts. This is a common problem for 3.2s
with the internal Paris-Rhone alternators.

 

I'm just curious if you ever figured out what the problem was?...my 80SC is now doing this too...

 

i just went through something like this but it was dimming.the seatbelt light went on.low voltage and a new alternator was the fix.everything is fine so far....

 

I cleaned the grounds and it hasn't changed. I haven't driven the car since, and it's going into winter storage soon, so I'll replace the voltage reg over the winter.

 

Yes, well i just went through that about 2 years ago...was a bugger to track down...my '80 normally had external regulator, but converted to one that is in the alternator (as we finally discovered)..The reason it was so puzzling was that the external regulator still resides inside the engine bay at its proper location and we couldn't understand why a new one wasn't helping...anywho. I can't imagine that’s the problem again (already). I'm gonna try the grounds first. And mine does the surging more when first started (cold). My car has a terrible idle hunt when cold too. and that doesn't help the surging lights one bit.

 

good luck saakey..i just got my 87 a month ago and its seen the shop 2 times.1400 bucks later i hope thats it for aa while...i love her..what a great car.more fun than the 95 i owned..