71 challenger headlight problems

[Dodgeguy62]

Okay guys I have a question, I was driving my car to work the other day, and my car started to overcharge. I had my headlights on, and I first noticed a pop then my high-beams turned on. Checked all my gauges and it was overcharging, played with the dimmer switch and I couldn't get my high beams to turn off, got to work and parked it. Next morning on my way home, same problem, except when I parked it, and turned the headlights off, my high beams stay on. I used a multimeter to check voltage output and was at 18.5V under throttle. Bought a new voltage regulator and it still over charges. So that's one issue I need addressed and thoughts on. Next is the headlights, I unplugged the dimmer switch and the high beams still stay on. I played with it a bit and couldn't figure it out. I let my dad play with it a bit while I was at work and he tore the instrumental cluster out and he said he disconnected the plug to the headlight switch and they still stayed on. Any thoughts on where to begin? Thanks

 

[js29]

Something is back feeding, both problems started at the same time. I would look at the bulkhead connector first. A wiring manual will help, you should get A factory service manual anyway. they are A big help in many different way's, I got mine on C-D from E-bay, good luck. mark.

 

[Dodgeguy62]

Thanks il check it out. I should've known better to get a manual for it cause even with my power wagon I always had electrical issues and the manual helped

 

[Dodgeguy62]

So I got the headlight issue fixed. It was the bulkhead connector in the firewall, melted the plastic insulation and was giving contact to the high beams. That issue is fixed, but I still have the overcharging issue. Put 3 different voltage regulators on it and all of them over charge. Two were brand new and one is used off of my 77 power wagon, all kept my power wagon under 15 volts under throttle, but none of them keep me from hitting 18+ on the challenger

 

[Adam]

Check the output at the alternator, If it is higher than 14-15 volts swap it out.
Is that 18+ showing on an old factory gauge? You should upgrade the old ammeter if you haven't already; they are a fire hazard.

That high voltage probably melted your bulkhead connector, meaning you need to do this upgrade:Vintage Chrysler electrical repairs and updates

"Simply connect the alternator output stud, via some serious gauge wire (matched to your alternator’s output specs) to the battery stud on the starter relay. But be absolutely sure you splice in an appropriate length of fusible-link wire into this new conductor!
With this done, the bulk of the charging system current will no longer flow through the firewall connector - or the ammeter. Obviously, the ammeter will no longer be accurate. The plan here is a simple accessory voltmeter, which should have its positive (+) side wired (with practically any gauge wire) to any ignition-switched 12-volt point, and the negative (-) side to ground."

 

[AUSTA]

So I got the headlight issue fixed. It was the bulkhead connector in the firewall, melted the plastic insulation and was giving contact to the high beams. That issue is fixed, but I still have the overcharging issue. Put 3 different voltage regulators on it and all of them over charge. Two were brand new and one is used off of my 77 power wagon, all kept my power wagon under 15 volts under throttle, but none of them keep me from hitting 18+ on the challenger

Check the ground on the regulator it needs it to sense the correct voltage check your engine to ground strap should be zero ohms between engine & firewall

 

[Dodgeguy62]

Check the output at the alternator, If it is higher than 14-15 volts swap it out.
Is that 18+ showing on an old factory gauge? You should upgrade the old ammeter if you haven't already; they are a fire hazard.

That high voltage probably melted your bulkhead connector, meaning you need to do this upgrade:Vintage Chrysler electrical repairs and updates

"Simply connect the alternator output stud, via some serious gauge wire (matched to your alternator’s output specs) to the battery stud on the starter relay. But be absolutely sure you splice in an appropriate length of fusible-link wire into this new conductor!
With this done, the bulk of the charging system current will no longer flow through the firewall connector - or the ammeter. Obviously, the ammeter will no longer be accurate. The plan here is a simple accessory voltmeter, which should have its positive (+) side wired (with practically any gauge wire) to any ignition-switched 12-volt point, and the negative (-) side to ground."

I was able to get 19v to the battery, 22v off the post on the alternator. I still have the factory ammeter hooked up, I am new to the e body world, I've been looking into the autometer direct fit kit, since I don't have a tach, and don't like the idea of a dummy light for oil pressure.. the alternator is the same on my power wagon so il swap them out and see if any other problems arise

 

[Dodgeguy62]

Check the ground on the regulator it needs it to sense the correct voltage check your engine to ground strap should be zero ohms between engine & firewall

0.3 ohms between ground and engine block, 2.8 ohms between ground post and radiator car support

 

[AUSTA]

0.3 ohms between ground and engine block, 2.8 ohms between ground post and radiator car support

>3 is fine actually it is the resistance of the meter leads so it is more likely 0
2.8 is too high is that from the engine to regulator bolt.
If the ground is good it could have a broken sensing wire between the alternator & the reg or a shorted brush holder not allowing the reg to do its job
Adam is right about bypassing the dash ammeter as everyone i have seen has the terminal all burnt along with the firewall connector.

 

[Dodgeguy62]

>3 is fine actually it is the resistance of the meter leads so it is more likely 0
2.8 is too high is that from the engine to regulator bolt.
If the ground is good it could have a broken sensing wire between the alternator & the reg or a shorted brush holder not allowing the reg to do its job
Adam is right about bypassing the dash ammeter as everyone i have seen has the terminal all burnt along with the firewall connector.

I got her fixed, the alternator from my 77 truck was the same alternator, so I took it off and swapped them out, now it's charging at 14.6 about 2500rpms, thanks for all your help guys! Next on the list is the ammeter fix

 

[Adam]

Check this link and read the articles, definitely a worthwhile upgrade:
Daniel Stern Lighting Consultancy and Supply