Holley RetroBright LED Headlamps for Positive Ground Cars
Posted by Kevin On 2022/8/26 12:09:23
Hi all. This question is specifically about the 12 volt, positive ground system in my 1955 Packard, but I'm guessing the general principles would apply to any positive ground Packard (or other car or truck), 6 volt or 12 volt, using a single sealed beam headlamp on each front fender.
I had to replace the crusty headlamp wiring harness in my car, as the cloth wire wrapping was flaking off and it was shorting out against the radiator support. While I was in there, I decided to try Holley's new RetroBright LED 7" headlamps. They fit just fine into the 1955's buckets, with zero modification needed. The reproduction headlamp harness connected right to the lamp, and all I needed to do was to attach the wires per the wiring diagram to the new junction blocks I got from Dwight Heinmuller.
Unfortunately, the headlamps wouldn't light. I had power from the battery and I had all my interior and exterior lighting illuminated when the headlight switch was pulled out to the first position. However, pulling the switch out to the Headlamps position resulted in no forward lighting whatsoever. The dash lights and side running lights and tail lamps were still lit, the parking lights turned off just like they should, but the headlamps remained dark.
I tried exchanging the positions of the BR-Brown and LT.G-Light Green wires from the headlamp harness on the junction block in case there was an issue of polarity inside the LEDs, something I'd run into before with a 2001 Camaro SS, but that also did not work.
Finally it was time to call in the big guns, and I appealed for help from one of my friends who is an electrical engineer. He spent a few minutes with it, swapped the ground wire and the low beam wire on the junction block, and the headlight came on! The bad news is that this arrangement would only allow me to use the low beams.
My question to our group is -- has anyone else used the Holly RetroBight on your positive ground car? What did you have to do to get both beams operational? Or are you getting by just with the low beams? It seems to be an issue of needing two ground wires instead of one, so that I would have a ground wire to also swap with the high beam wire on the junction block. I would then end up with the BR-Brown and LT.G-Light Green wires fastened to the fender splasher with a screw where the black ground wire used to be.
Admittedly, I don't see myself driving my car anywhere that late at night and needing the use of high beams, but I'm one of those OCD guys who thinks everything should operate properly as designed! Any help and advice would be welcomed!
Attached is an excerpt of the 1955 wiring diagram, edited to focus just on the forward lighting.
Attach file:
1955-56 Headlamp Wiring Diagram.pdf Size: 63.50 KB; Hits: 66
I had to replace the crusty headlamp wiring harness in my car, as the cloth wire wrapping was flaking off and it was shorting out against the radiator support. While I was in there, I decided to try Holley's new RetroBright LED 7" headlamps. They fit just fine into the 1955's buckets, with zero modification needed. The reproduction headlamp harness connected right to the lamp, and all I needed to do was to attach the wires per the wiring diagram to the new junction blocks I got from Dwight Heinmuller.
Unfortunately, the headlamps wouldn't light. I had power from the battery and I had all my interior and exterior lighting illuminated when the headlight switch was pulled out to the first position. However, pulling the switch out to the Headlamps position resulted in no forward lighting whatsoever. The dash lights and side running lights and tail lamps were still lit, the parking lights turned off just like they should, but the headlamps remained dark.
I tried exchanging the positions of the BR-Brown and LT.G-Light Green wires from the headlamp harness on the junction block in case there was an issue of polarity inside the LEDs, something I'd run into before with a 2001 Camaro SS, but that also did not work.
Finally it was time to call in the big guns, and I appealed for help from one of my friends who is an electrical engineer. He spent a few minutes with it, swapped the ground wire and the low beam wire on the junction block, and the headlight came on! The bad news is that this arrangement would only allow me to use the low beams.
My question to our group is -- has anyone else used the Holly RetroBight on your positive ground car? What did you have to do to get both beams operational? Or are you getting by just with the low beams? It seems to be an issue of needing two ground wires instead of one, so that I would have a ground wire to also swap with the high beam wire on the junction block. I would then end up with the BR-Brown and LT.G-Light Green wires fastened to the fender splasher with a screw where the black ground wire used to be.
Admittedly, I don't see myself driving my car anywhere that late at night and needing the use of high beams, but I'm one of those OCD guys who thinks everything should operate properly as designed! Any help and advice would be welcomed!
Attached is an excerpt of the 1955 wiring diagram, edited to focus just on the forward lighting.
Attach file:
1955-56 Headlamp Wiring Diagram.pdf Size: 63.50 KB; Hits: 66This Post was from: https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=247454