Headlings, dash lights, guage lights, tach light, all flicker while driving at night.

What could it be? alternator?

IF you have the stock alternator that uses the remote regulator on the fender well or firewall, then, there is a way to fix this.

Stock regulator is turning the alternator on and off, on and off.

Change to a Wells VR715 regulator, should stop it. Auto Zone carries them, they are not expensive.

The Wells regulator is electronic, keeps the alternator on all the time, dumps the excess charging voltage to ground, just like the later internally regulated alternators do.

Stock regulator turns the alternator on to charge, then, when the battery is full, off, then, back on, etc. This is where the "flickering" comes from.

Regards,

Milton

Had the same problem and was a ground that was loose. Check to see if grounds are good.

IF you have the stock alternator that uses the remote regulator on the fender well or firewall, then, there is a way to fix this.

Stock regulator is turning the alternator on and off, on and off.

Change to a Wells VR715 regulator, should stop it. Auto Zone carries them, they are not expensive.

The Wells regulator is electronic, keeps the alternator on all the time, dumps the excess charging voltage to ground, just like the later internally regulated alternators do.

Stock regulator turns the alternator on to charge, then, when the battery is full, off, then, back on, etc. This is where the "flickering" comes from.

Regards,

Milton


I read that these Wells VR715 regulators must be grounded to the motor to work. Does a factory wiring harness for a '71 do this or will a wire have to be added? My lights are flickering at night and I want to switch over to a Wells VR715 but I want to do it right.

Had the same problem and was a ground that was loose. Check to see if grounds are good.
X2:thumbsup::thumbsup:

Anyone know if this AutoZone part is the same as the Wells?

http://www.autozone.com/autozone/catalog/parts/partsShelf.jsp?categoryDisplayName=Electrical+%26+ Lighting&fromType=parts&fromString=search&parentId=57-0&currentPage=1&filterByKeyWord=VR715&isSearchByPartNumber=true&navValue=15700097&categoryNValue=15799999&fromWhere=&itemId=97-0&displayName=Voltage+Regulator&searchText=VR715

Personally, I'd make life a lot easier on myself and just switch to the far superior internal reg alternator. Not hard to do, and the alternator will be a lot easier to come by if you have a failure on the road. I'd first check all the grounds though. Jim.

I went over most of the grounds, and they are all tight, clean, and making good contact. I drove home from a car show last night and it did it all the way home.

Personally, I'd make life a lot easier on myself and just switch to the far superior internal reg alternator. Not hard to do, and the alternator will be a lot easier to come by if you have a failure on the road. I'd first check all the grounds though. Jim.

What kind would you suggest?

The Wells regulator turns the alternator operation into exactly the same as the internally regulated alternators, no difference.

Regards,

Milton

Anyone know if this AutoZone part is the same as the Wells?

http://www.autozone.com/autozone/catalog/parts/partsShelf.jsp?categoryDisplayName=Electrical+%26+ Lighting&fromType=parts&fromString=search&parentId=57-0&currentPage=1&filterByKeyWord=VR715&isSearchByPartNumber=true&navValue=15700097&categoryNValue=15799999&fromWhere=&itemId=97-0&displayName=Voltage+Regulator&searchText=VR715

I tried it and it took care of the flickering lights at night problem! :hurray:

Only down-side is you can't put the original cover on it like the Wells. :( I just bought a Wells VR715 that already has the original restored GM cover on it off Ebay. I'll put it on after I receive it and put the AutoZone one on my old truck.

I had the same thing happen in the Mustang and a gound came loose. It's always good to see at night.:D

Sorry to dredge this one up again, but.......

My '69 SS is all stock, replaced the VR with the Wells unit, and the headlights and dash lights still flicker when on. What grounds are you guys inspecting?

Thanks!

Before you go crazy, try tapping on the alternator with a hammer handle while running.
Sometimes brush dust gets between the brushes and the commutator. Tapping on mine cleared the problem right up.

Does the flicker vary with engine speed? If so, it could be an alternator defect.

Before you go crazy, try tapping on the alternator with a hammer handle while running.
Sometimes brush dust gets between the brushes and the commutator. Tapping on mine cleared the problem right up.

Does the flicker vary with engine speed? If so, it could be an alternator defect.

Thanks guys, I'll have to try tapping, and pay more attention to whether the flickering varies. IIRC, it does not vary.

Bought one of those hand held battery and charging system testers. The needle fluctuates when the engine is running, especially with high beams and blower on. Running 2 separate tests, it indicates the rectifier and diode trio need replacement.

Old thread but having a flickering headlight problem as well. Headlights are run off of dual relays and are Hella halogen. I checked all of the grounds and everything looks good. Dash lights are unaffected. Alternator is an internally regulated Autozone unit. It just started happening recently. Any ideas? I read somewhere that the headlight switch could be the culprit. If so is it a simple (not on a '67) replace or does something need to be done to the wiring in addition to getting a new switch? Any help/ideas would be appreciated.

Bought one of those hand held battery and charging system testers. The needle fluctuates when the engine is running, especially with high beams and blower on. Running 2 separate tests, it indicates the rectifier and diode trio need replacement.

Have an update. I replaced the alternator with a correct date coded alternator that I had rebuilt at a local, reputable electrical shop. They even demo'd it for me. Once installed, the lights were still flickering. I switched the Wells voltage regulator with a known good AC Delco mechanical type piece and the lights still flickered, but very intermittently. At times they would flicker, then would stop for quite a while with no noticed pattern. I noticed from my hand held gauge that the lights would flicker only when charging output exceeded 15 volts, but quickly returned into the 14 volt range. Keep in mind this only happens when the lights are turned on. I should probably try this with the blower motor on.

Some old timers told me to replace the headlight switch, so I replaced it with an AC Delco part. So far, as Xplantdad can attest to, no flickering. :D

Took the old switch apart and found the contacts very worn, but never did find out what was rattling around inside it. There was also some greeen substance in there that STANK!

Not entirely convinced this is "the" fix, but so far, so good.

Have an update. I replaced the alternator with a correct date coded alternator that I had rebuilt at a local, reputable electrical shop. They even demo'd it for me. Once installed, the lights were still flickering. I switched the Wells voltage regulator with a known good AC Delco mechanical type piece and the lights still flickered, but very intermittently. At times they would flicker, then would stop for quite a while with no noticed pattern. I noticed from my hand held gauge that the lights would flicker only when charging output exceeded 15 volts, but quickly returned into the 14 volt range. Keep in mind this only happens when the lights are turned on. I should probably try this with the blower motor on.

Some old timers told me to replace the headlight switch, so I replaced it with an AC Delco part. So far, as Xplantdad can attest to, no flickering. :D

Took the old switch apart and found the contacts very worn, but never did find out what was rattling around inside it. There was also some greeen substance in there that STANK!

Not entirely convinced this is "the" fix, but so far, so good.


I've had this issue on my 70. twice. 1st time was the headlight switch. 2nd time was actually a worn out dimmer switch on the floor. Replaced the dimmer, all was well.

I'm old enough to remember that ALL the old cars did this when the battery got fully charged. (well, all the ones that I drove anyway)