Negative ground conversion

MikeG · 2026-03-16T10:26:33-0600

Im thinking of converting to negative ground so I can run aftermarket LED turnsignals and tail light. I have Powerarc ignition and Podtronics regulator that I know need to be switched over. I cant think of anything else that might be polarity sensitive but thought I'd ask anyway. My wire harness is home made, everything on its own fused circuit and all grounds go to a common buss bar before hooking to battery. Anything else I might have overlooked?

gpzkat · 2026-03-16T10:56:41-0600

I'd be tempted to use a 20A polarity-reversing adapter, as I see on eBay for $11 or so. Maybe someone has tried and will chime in.

Tornado · 2026-03-16T11:08:26-0600

Most LED lights can now be had polarity insensitive so thats not a reason to switch to neg 'erf. There are some devices that do require it, like turn signal cancel or brake light flashers etc.

kommando · 2026-03-16T11:08:47-0600

There are plenty of positive earth bulbs around, even the ones that do not mention it are dual polarity due to the voltage protection circuitry. I changed my Commando to negative earth back in the 80's to allow fitment of an alarm that grounded through its case, as soon as it broke I converted back. Having to carry a dedicated circuit diagram around was a pain as was having to think about all the changes I had done including the zener.

Lineslinger · 2026-03-16T11:18:11-0600

Mike, if you built your own harness and made all those connections/confgurations yourself I think you would be able to see gremlin lurking in there. All I could suggest is to crawl through all of it one more time to look for a wiring or connection ambush you missed or forgot.
I left my system pos+ ground and bought LED bulbs/fixtures already adapted for such.

2WheelsUp · 2026-03-16T12:37:27-0600

MikeG said:
Im thinking of converting to negative ground so I can run aftermarket LED turnsignals and tail light. I have Powerarc ignition and Podtronics regulator that I know need to be switched over. I cant think of anything else that might be polarity sensitive but thought I'd ask anyway. My wire harness is home made, everything on its own fused circuit and all grounds go to a common buss bar before hooking to battery. Anything else I might have overlooked?

Contact Greg Marsh. He either has or can refer you to, LED bulbs for headlight, taillight, turn signals and indicator lights that are inexpensive and work for positive ground. There is a minor mod for the turn signal indicator that he can walk you through.

Negative ground conversion

MikeG

Mikeg

gpzkat

Tornado

kommando

Lineslinger

2WheelsUp

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