Flickering Head Lights

[healey]

I finally got my newly acquired 1988 Carrera Targa on the road after a winter project of refurbishing the interior. Drove it for the first time tonight and noticed that the headlights and blinker lights would flick unless the revs were well over 4000 rpm. Battery is fully charged and warning alternator warning light does not come on even at idle. I suspect this has something to do with the alternator but not sure how to chase down the problem. Any suggestions?
Thanks for any input or suggestions.

[Barrpete]

Could be the voltage regulator going bad. Had a similar problem a while back and it turned out to be the VR. I bought one of those volt meters that plug into the cigarette lighter for a few bucks at the FLAPS and found that the voltage was spiking up over 15V.

If that's the case, the voltage regulator is attached to the alternator so you'll have to remove it to replace the VR. There's an excellent tutorial in the tech info center on removing the alternator.

[fitchn]

Also check the ground stap on the transmission, I've seen an SC have blinky headlights when this was failing.

[darrin]

on my '86, my seatbelt warning light would also come on when a particularly large voltage spike came through -- have you been having any seemingly random seatbelt warnings?

[wwest]

Storage...

You need to go through and disconnect/clean/burnish/tighten all main electrical connections front to rear. Battery posts, battery ground connection point, battery/alternator connect at the starter motor, and yes the engine/tranaxle to chasis ground.

[Chrisdmm]

I just did this last week. Had the seat belt warning light come on/off every few mins, voltage spikes in the 16-17 range and dimmining headlights.

Took the time to clean up the fan/shroud with some engine paint and replaced the voltage regulator. Car runs great now and no more electrical gremlins.

[darrin]

chrisdmm -- be sure to check under/around your battery for evidence of boiled over battery acid -- stuff could also drip below your battery area to a front cross-member.

[Chrisdmm]

Checked the whole front area, everything is clean, cleaned up -/+ ends and added battery tender terminals.

[DRACO A5OG]

Originally Posted by Chrisdmm

I just did this last week. Had the seat belt warning light come on/off every few mins, voltage spikes in the 16-17 range and dimmining headlights.

Took the time to clean up the fan/shroud with some engine paint and replaced the voltage regulator. Car runs great now and no more electrical gremlins.

16-17 volts is way too much VR is failing, swap asap

[healey]

Thanks all for the tips. I will check all the grounds and connections. Is there a diagram available that shows where all the ground locations are located in the car? Will also check the voltage regulator.
Regarding seat belt lights my does not come on. Any suggestions with that?
Thanks again for all replies.

[Omegablueray]

I had the same thing with my 85'. I change the alternator and the problem was solved. I believe it was probably the voltage regulator, however, if its an original alt change to whole thing you only want to get in there once. The voltage regulator is mounted on the alternator. Very doable but it will take 3-4hrs if you've never done it before. Great time to powder coat your fan/fan housing. Good luck

[Omegablueray]

[healey]

Ordered a Voltage regulator and installed it and that fixed the problem. Thanks everyone for pointing me in the right direction. Also cleaned and painted the fan shroud and blade since it was out. Looks real nice.
Now I just need to do something about those awful H5 headlights. Would like to get some H4's when the bank account allows.