bartman Posted February 4, 2017 Share #1 Posted February 4, 2017 On my 73 240Z my headlights seem to work properly with the stock wiring, but it seems backwards. When the lights are turned on the black wire gets power while red/black is ground when using low beams and red/white is ground when using high beams. This causes problems when trying to upgrade my lights to use relays. This can't be correct can it? And if so, what could be causing this? Link to comment Share on other sites More sharing options...
zKars Posted February 4, 2017 Share #2 Posted February 4, 2017 (edited) You're lights are wired correctly. This is the way they come from the factory. The high/low switch decides which side gets grounded (RW or RB) while the common bulb terminal is fed constant +12 via two fuses. The Dave Irwin relay upgrade harness reverses this situation without issue in a most elegant manner. All is fine, carry on with your day. Edited February 4, 2017 by zKars 1 Link to comment Share on other sites More sharing options...
bartman Posted February 5, 2017 Author Share #3 Posted February 5, 2017 Thanks. I looked through a lot of threads and didn't see this information anywhere. Link to comment Share on other sites More sharing options...
SteveJ Posted February 5, 2017 Share #4 Posted February 5, 2017 It's actually been explained many times: And it's documented completely in the FSM in the BE section with the wiring diagram. 1 Link to comment Share on other sites More sharing options...
bartman Posted February 5, 2017 Author Share #5 Posted February 5, 2017 I stand corrected. I think the main thing throwing me off on my car is the right headlight power feed is black not red. I generally don't expect to see power coming from a black wire. Link to comment Share on other sites More sharing options...
siteunseen Posted February 5, 2017 Share #6 Posted February 5, 2017 That'll change if you ever do any house wiring. 2 Link to comment Share on other sites More sharing options...
SteveJ Posted February 5, 2017 Share #7 Posted February 5, 2017 17 hours ago, bartman said: I stand corrected. I think the main thing throwing me off on my car is the right headlight power feed is black not red. I generally don't expect to see power coming from a black wire. Clarify what you mean. Where exactly is the black wire? There is a White/Red wire in the dash harness taking 12 VDC+ to the combo switch. The headlights contact in the combo switch will connect to a Red wire in the dash harness that goes to the fuse box. The black wire in the dash harness is the ground for the headlight switch and the horn. Link to comment Share on other sites More sharing options...
bartman Posted February 5, 2017 Author Share #8 Posted February 5, 2017 I'm talking about the wires at the headlight bulb connection. Link to comment Share on other sites More sharing options...
SteveJ Posted February 5, 2017 Share #9 Posted February 5, 2017 It's been 15+ years since I worried about the wires on the connector. The wire colors in the dash harness, body harness and engine harness are what you need to concern yourself with for colors. Those are the ones listed in the FSM. Link to comment Share on other sites More sharing options...
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