Headlight electrical issue help 66 sport fury

[HOT FURY]

So I'm stumped. My headlights and instrument cluster pulsing while engine is running. They aren't going on and off but more like intensity pulsing and I cant figure out the issue.
The car has a new engine harness, bulkhead connector redone, dash wiring & fuse block redone, new painless wiring headlight harness with relays, new 90 amp alternator, new electronic voltage regulator, new headlight dash switch. Nothing else seems to pulse other than the instrument cluster backlighting and headlights and only while running. While running I used my multimeter to check the charging voltage on the battery terminals and its alternating back n forth from approximately 14.5V to 15.25V.

Any ideas would be great. Short somewhere? alternator bad? voltage regulator bad? ammeter going bad? or?

 

[mrfury68]

Make sure all your ground connections are good and you have a block to chassis ground.

 

[Ross Wooldridge]

Bad alternator perhaps? Bad voltage regulator? Poor grounds making voltage regulator ask for voltage then gets it, then asks, then gets it... ??

 

[HOT FURY]

Ground connections should be good. I installed new heavy duty ground straps from the block to the frame and body when redoing the engine wire harness but can double check all of them to make sure good clean connections.

 

[Ross Wooldridge]

Sounds like a diode could be bad in the alternator. I had a pulsing alternator and that was the problem.

 

[Big_John]

I'm leaning towards this being a bad voltage regulator, but the electronic versions tend to just not work over doing something like this.

As said, check all the connections, including the back of the ammeter.

 

[rkrochen]

I'm leaning towards this being a bad voltage regulator, but the electronic versions tend to just not work over doing something like this.

As said, check all the connections, including the back of the ammeter.

I agree. Try a new voltage regulator first. Just because it was replaced doesn’t mean it’s good. Took me 3 try’s to get a good one. Usually if an alternator is bad it just won’t charge properly. But as said previously confirm that all connections and grounds are good.

 

[FURYGT]

Why so you need a 90 amp alternator? If you are using an electronic solid state voltage regulator like the ones that I sell, Mopar Voltage Regulator - Electronic Solid State with Correct Restoration Look | eBay
they are only rated up to 60 amps and you may have damaged it. Voltage around 15 volts tells me that the voltage regulator is not working properly and in my opinion, you should not drive the car if your are getting 15 volts at the battery while running. I hope that you upgraded all of the wiring in the charging circuit and bypassed the amp gauge. If you didn't, you risk your car catching on fire. You need to use the 1970 & later voltage regulator and use a heavier gauge wire in your charging circuit with a 90 amp alternator.

 

[HOT FURY]

Why so you need a 90 amp alternator? If you are using an electronic solid state voltage regulator like the ones that I sell, Mopar Voltage Regulator - Electronic Solid State with Correct Restoration Look | eBay
they are only rated up to 60 amps and you may have damaged it. Voltage around 15 volts tells me that the voltage regulator is not working properly and in my opinion, you should not drive the car if your are getting 15 volts at the battery while running. I hope that you upgraded all of the wiring in the charging circuit and bypassed the amp gauge. If you didn't, you risk your car catching on fire. You need to use the 1970 & later voltage regulator and use a heavier gauge wire in your charging circuit with a 90 amp alternator.

Thank you I think you may have hit the nail right on the head with my problem! I did buy one of your electronic voltage regulators which is on it and that explains why the pulsing didn't happen immediately after all of the electronic upgrades and new wiring. I totally missed that part of the description on your ebay site about the max 65 amp alternator restriction, hopefully I haven't fried anything else. I did upgrade everything else in the charging circuit properly to accommodate the higher amp alternator so not worried about that part. I put the higher amp alternator in to accommodate the extra load the stereo system and some of the other non factory electronics going into the car.

 

[CBODY67]

I would suspect that pulsing would be a voltage regulator issue. You did not mention the voltage limiter for the instrument cluster?

 

[FURYGT]

Thank you I think you may have hit the nail right on the head with my problem! I did buy one of your electronic voltage regulators which is on it and that explains why the pulsing didn't happen immediately after all of the electronic upgrades and new wiring. I totally missed that part of the description on your ebay site about the max 65 amp alternator restriction, hopefully I haven't fried anything else. I did upgrade everything else in the charging circuit properly to accommodate the higher amp alternator so not worried about that part. I put the higher amp alternator in to accommodate the extra load the stereo system and some of the other non factory electronics going into the car.

I know that some folks have not had problems with alternators rated higher than 65 amps but 90 amps is significantly higher. Get a '70 & later voltage regulator and wiring harness and make that upgrade.

 

[1970FuryConv]

I know that some folks have not had problems with alternators rated higher than 65 amps but 90 amps is significantly higher. Get a '70 & later voltage regulator and wiring harness and make that upgrade.

Agree with you on the voltage regulator. I'm not sure that the 1970 and later flat pack electronic voltage regulator can handle 90 Amp alternator.

Are you saying that it definitely can handle 90 amps? Thanks

 

[FURYGT]

Agree with you on the voltage regulator. I'm not sure that the 1970 and later flat pack electronic voltage regulator can handle 90 Amp alternator.

Are you saying that it definitely can handle 90 amps? Thanks

I’m not saying that.

 

[HOT FURY]

They used those same basic electronic regulators into the mid 80's I believe so should be able to handle the alternator since many of the vehicles were coming with higher amp alternators by then.

 

[thethee]

Agree with you on the voltage regulator. I'm not sure that the 1970 and later flat pack electronic voltage regulator can handle 90 Amp alternator.

Are you saying that it definitely can handle 90 amps? Thanks

If I'm reading my FSM right my 1975 Imp came with a 100 amps alternator from factory so I'm guessing the voltage regulator would be okay with 90 amps. Don't know if that regulator was used across the board though, or across the years, but mine is still doing it's job.

 

[Ross Wooldridge]

I would use the correct VR for that 75 Imp then.

 

[1970FuryConv]

If I'm reading my FSM right my 1975 Imp came with a 100 amps alternator from factory so I'm guessing the voltage regulator would be okay with 90 amps. Don't know if that regulator was used across the board though, or across the years, but mine is still doing it's job.

May I see a pic of the voltage regulator you are using? Thanks!

 

[thethee]

This is the best pic I have for now and it'll be a while before I can get a better one if you need it.

Lucky #1000

 

[thethee]

May I see a pic of the voltage regulator you are using? Thanks!

Well I said a while but I didn't plan on almost a month and a half... Don't know if you still need it but I pulled it out to get you a close up pic. The numbers read 1601 12V and those are the only markings on it. Don't even know if it's original to the car but this is what I've got.