Datsunpowers Posted January 30, 2023 Share Posted January 30, 2023 For a couple years I have researched LED headlights for my 71 240Z. I wanted a headlight that had a great beam pattern and looked like a stock headlight. The headlight I choose was the Holley Retrobright LED headlights in Modern White from Headlight Revolution. Here is the link Holley RetroBright Classic LED Sealed Beam Headlights | 7" Round (headlightrevolution.com). The Headlight Revolution website has great information and testing results on LED headlights. The good news is the headlight fits and plugs into the stock headlight bucket without any modification. I have used these LED headlights for several months now and I really like them. I now enjoy driving the car at night and see the road and deer in front of me for a change! They are pricy, but you get what you pay for here. With these LED headlights the current draw is significantly lower than the stock headlight current draw. This means I can use the stock 240Z wiring harness by swapping two wires in the headlight switches. This swap changes the polarity needed for the LED headlights. I was going to use the Hella H4 headlights and did test them, but it would have required a new headlight harness to handle the increased current draw. Here are the different headlights I tested and amp draw. Here is the 240Z light switch modification that’s required to switch the headlight plug polarity for the LED headlights. This wiring modification is completely reversible. You will need the following materials. Materials needed: 1. ATO fuse holder with wiring extension 2. 15 amp ATO Fuse 3. 14 Gauge jumper wire 4. 2 Female bullet connectors 5. 2 Male bullet connectors 6. Voltmeter or Test Light for testing LED Jumper Wiring Modification with ATO Fuse Holder Wiring Procedure: (Pictures below) 1. Remove the steering column cover. 2. Unplug the Black wires from the Lower Headlight Switch and the High Low Switch. 3. Unplug the Red wires from the Upper Headlight Switch and the wire that runs to the headlight fuse block. This is the red common connection to the LH and RH Headlight fuses. 4. Connect the Red wire from the Upper Headlight Switch to one side of the ATO fuse holder. Note: you will have to extend the wires on the ATO fuse holder, so you can access the fuse holder with the steering cover on. 5. Connect the Black wire from the High Low Switch to the other side of the ATO fuse holder. 6. Insert a 15 amp fuse in the new ATO fuse holder. This is now your headlight fuse for both LED headlights. The headlight 12v power comes from the headlight switch. 7. Make a 2” long jumper wire with a male and female bullet on each end. 8. Connect Black lower headlight switch female bullet connector to the male jumper. 9. Connect the Red from the Common LH and RH Headlight fuses male bullet to the female jumper wire. 10. Now you have switched the polarity at the headlight plugs. To test your connections you can use a Voltmeter or Test Light. At the headlight plug you will have one common ground and 12v+ for the high and low beam. 11. Install the new LED headlights and adjust the beam pattern per the FSM. This so you get the best beam pattern and you will not blind oncoming traffic. 12. Reinstall the steering column cover very carefully. (The plastic screw holes in the cover like to crack and strip out very easily). LED Jumper Wiring Modification with ATO Fuse Holder Installed Upper Headlight Switch High Low Beam Switch Headlight plug electrical outputs before modification Headlight plug electrical outputs after LED wiring modification 240z FSM Headlight Wiring Diagram Holley Part Number 71 240z Holley Retrobright LED Headlights These Holley LED headlights bring the headlights up to modern standards with a classic look. The have a great beam pattern that really lights up the road when you're driving and don't blind other drivers. They come in different colors and the LED bulbs are replaceable. I choose the Modern White color vs. Classic White. They really have worked well for me so far! Quote Link to comment Share on other sites More sharing options...
DuffyMahoney Posted January 31, 2023 Share Posted January 31, 2023 Thanks for the write up, I would have never thought it would need a harness Quote Link to comment Share on other sites More sharing options...
Mike Mileski Posted February 20, 2023 Share Posted February 20, 2023 How did you know that you needed to change the polarity? Did that information come in the instructions with the Holley LED headlights? Mike Mileski Tucson, AZ Quote Link to comment Share on other sites More sharing options...
Datsunpowers Posted February 23, 2023 Author Share Posted February 23, 2023 Mike the headlights didn’t have any polarity instructions with them. They did work out of the box in my 69 Camero. When I plugged them in my 240z they didn’t work. This is when I discovered the wiring polarity on the 240z is a non-standard H4 plug. With incandescent bulbs polarity doesn’t matter, but with LED lights it does. Here is a standard H4 plug and the non-standard H4 plug on the 240z. Switching two wires at the headlights switch corrects the polarity for a standard H4 plug. I am sure this applies to other H4 LED bulbs, but I don’t have experience with them. Quote Link to comment Share on other sites More sharing options...
Mike Mileski Posted February 24, 2023 Share Posted February 24, 2023 Wow, I'm always learning something new. Thanks for the info. Mike Mileski Tucson, AZ Quote Link to comment Share on other sites More sharing options...
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