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Hummer H3For the Hummer driver who wants the rugged look and off road capabilities of the Hummer, but in a smaller size and with a more fuel economy friendly engine.
Hi! New user here! I've had my 2007 H3 for about 2.5 years and the headlights have been nothing but a pain for the entire time. The previous owner am had installed cheap LED bulbs that made the dashboard light up like a Christmas tree. I switched to higher end bulbs which solved the dash lights but after a few months they started flickering and then went completely out. I then switched to regular halogen bulbs which worked fine until a few weeks ago when one of the started turning off and and on randomly.
I decided to finally bite the bullet and replace the whole light assembly and get quality projectors with a good wiring harness. After reading up on forums and watching a bunch of YouTube videos, I decided to try the Morimoto super7 LED projectors. I also purchased a wiring harness from them. When the parts came I noticed that the harness and lights didn't fit together right. I emailed them and was told that I shouldn't have bought the harness because the H3 doesn't need a harness or adapters (since I bought the lights with H13 connectors). So today I did all the with of retrofitting the 7 inch lights into the H3 housing. When I finished one I plugged it in to test it and the light worked but high and low beams were reversed. I wondered if there was something funny going on with the wiring because the other light still had the original bulb. So I pulled the bulb out of the other side and plugged in the Morimoto. Then I tested and neither lights come on!! I can still here the projector changing position between high and low but no lights either way. Now I'm super confused.
Anybody know what's going on here?
I've gotten pretty handy with electrical so I'm down to reroute wiring if I can figure out what I'm dealing with.
I'm guessing the Morimoto LED, like most aftermarket 7" LED units, uses a switched 12V input for the hi/low input to the bulb where it expects the vehicle circuit will provide power to only the high beam or only the low beam at one time, and then uses a common ground connection to complete the circuit. That's the way jeep does it.
The H3 factory wiring using a switched ground control where a single 12V input feeds both the high and low inputs to the bulb simultaneously, then switches the ground leg to complete the hi/low circuit. It is not a switched 12V input like the Jeeps.
To make the 7" aftermarket LED headlamps work in the H3 you will need a negative switched conversion harness to make them "plug and play." I used this one when I converted to 7" LED bulbs:
For reference, here's the 2007 H3 headlamp schematic where you can see how the ground leg of the circuit is what gets switched. Because current will only flow one way through an LED you can't just use an adapter connector and run power through the circuit backwards. Instead, you will need to install a relay harness that changes the polarity of the entire switching circuit.
Thanks for the help and advice everyone! I needed to get the lights running by the end of the day so I didn't have time to wait for a harness. But I made my own and it worked great! I was hesitant to do so before because I didn't want to break anything doing trial and error. Anyway, I'm back in business and the new lights are awesome!
Not sure how the Super7s work, I have Morimoto M LED 2.0s in my h3 and it has a controller box and all. It works fine except for high beams due to the design of the wiring in the h3 but thats easily fixed with a relay