70 Charger headlight door trouble

[Coronet guy]

Today I installed a new set of LED headlights in my 70 charger R/T, all of the lights fit and worked as they should. The problem is that when I go to shut the lights off when it’s in the low beam setting, the headlight doors won’t close upon shutting off. When the lights are on high beams, the doors will close and everything works fine.When it comes to turning them on in either low / high position, the doors will open normally. Any help would be greatly appreciated.

 

[Kern Dog]

The headlight door relay, located below the instrument panel in the dash, can be tricky.

I installed relays in my headlight system and found that trace amounts of voltage was leaking from the stock headlight door (Concealed lamp door) relay and messing with the headlight door motor operation.
In 2013, a buddy tried to help me change a few things in the wiring and we encountered the same thing.
I found that the fix was to abandon the factory relay and wire in a Bosch 5 pin relay.

Zero problems since.

 

[6PKRTSE]

Mine both cars still works flawlessly off of the factory relay. In fact, they have always seem to work to good. They flip up and slam closed so fast it almost sounds like they would break something. Never been an issue though, or broke anything.

 

[Coronet guy]

Thank you for your help with this, I finally found out what the problem was, I needed a couple of 6ohm resistors on the low beam lights. The doors worked perfectly on the high beams, but when switched on to low beams, that’s when things started to act up. I did some digging and found that the low beams weren’t drawing enough power to make the relay circuit work properly, so I installed the resistors and everything is working perfectly fine now.

 

[Kern Dog]

Score!
It is great when we finally figure out the problem.

 

[Triplegreen500]

I was going to say it could be a draw issue...I have HID lows and LED highs and mine work fine...but I also have a late-model relay so that would have been zero help.

Glad you got it sorted! (and 6PKRTSE, I'm glad I'm not the only one who thinks his front end is going to fall off when those doors SLAM shut!)

 

[Richard Cranium]

Thank you for your help with this, I finally found out what the problem was, I needed a couple of 6ohm resistors on the low beam lights. The doors worked perfectly on the high beams, but when switched on to low beams, that’s when things started to act up. I did some digging and found that the low beams weren’t drawing enough power to make the relay circuit work properly, so I installed the resistors and everything is working perfectly fine now.

If you don't mind me asking, how did you figure that out?

 

[Mike D]

If you don't mind me asking, how did you figure that out?

Agreed, my doors don't move at all, is there a troubleshooting post somewhere, on how to check voltage and make sure the motor is good? The lights come on but the doors don't open.

 

[70gtx440dana]

Check for power at your HL motor with light switch on. Two wire connector at motor. One lead is for open and one lead is for close. If you want to test the motor you can do so with a jumper wire direct from battery. Disconnect two wire connector and put power to each side. The most likely cause is a bad HL motor relay...it is mounted under LH side of dash on a 70 Charger.

Agreed, my doors don't move at all, is there a troubleshooting post somewhere, on how to check voltage and make sure the motor is good? The lights come on but the doors don't open.

 

[Mike D]

Check for power at your HL motor with light switch on. Two wire connector at motor. One lead is for open and one lead is for close. If you want to test the motor you can do so with a jumper wire direct from battery. Disconnect two wire connector and put power to each side. The most likely cause is a bad HL motor relay...it is mounted under LH side of dash on a 70 Charger.

Thanks. I now confirmed the motor does work, so I'll check out the relay next.

 

[70gtx440dana]

Thanks. I now confirmed the motor does work, so I'll check out the relay next.

Message me if you need a restored original HL motor relay. I have a couple on hand. Joe

 

[cavaleiro95]

Message me if you need a restored original HL motor relay. I have a couple on hand. Joe

Do you have any more relays?

 

[fastmark]

Hey guys, I’m resurrecting this old thread because I’ve got problems with 70 Charger as well. Using all the stock bulbs and relays with the original headlight motor restored, everything worked fine. You just could not see at night! Lol. I did have wiring problems with my new M and H harness, though. They installed the wires swapped on my plug in under the dash for the relay and the doors opened when the light were turned off and vice versus. I did fix that.
Now I’ve installed the Holley retro lights and the doors only operate with the high beams on. Sometimes going down the road on high, the relay starts to click and the lights go off the on. I was told to put a 15 amp load resistor to each low beam to solve the problem. My concern is that a 15 amp would load the original wires too much and give the same trouble as the old incandescent and burn out the dimmer switch plug like they could do. I don’t really want to change the relay to the new Bosch if the 6 ohm will work an not load the wires as much. Want more input would help.

 

[fastmark]

Thanks to Kerndog for the diagram. I finally had time to wire up a new five pin relay and it works fine now. It was doing crazy things. I could make the headlight doors open and close with the dimmer switch and headlights off. It had to be a bleed back issue. I just did not want to put resistors in the low beams because the main purpose in my case is to take the load off of the wires. My biggest problem was going down the road at night with the high beams and all the headlights would just go off.