Did the mod today - not sure if it's been mentioned somewhere or not, but my truck's low beam power wire is NOT the brown wire. It's tan. There is both a tan and brown wire in my loom, but the tan wire is the one going to the low beam. Could be because my truck is a Canadian built truck with DRLs? Also, I installed this under the ECM like a few others have. It makes so much more sense and might actually save a bit of time and money. It makes the inline fuse redundant and means you don't actually have to purchase any wire if you buy a relay with the female pigtail.
1. Attach single eyelit connector to the ground wire of pigtail. Feed under relay mount bracket and use self tapping screw to secure to inner fender liner beneath ECM. This will be pin #85 on your relay.
2. Attach large eyelit connector to power wire of your pigtail. Run beneath ECM bracket to fuse block, and secure to power post Aux A in the fuse block using M8 x 1.25 nut. This power post is designed for this type of connection and is already fused by 30A MAXI fuse inside the block. This is pin #30 in the relay.
3. Fish light/lime green wire and tan/brown wire (guess it is dependant on year/model/VIN) out of the wire conduit beside ECM bracket.
4. Either strip or cut green wire from wire conduit and attach to switch wire of pigtail. I stripped mine and wrapped the pigtail wire around the wire, then soldered. I would cut the wire if I did it again so I could get heatshrink on and make a better connection by intertwining copper wire strands. This is pin #86 on your relay.
5. Either strip or cut brown wire from wire conduit and attach to output wire of pigtail. I did the same as above, but if I was doing it again I would also cut and do a better job. This is pin #87 on your relay.
6. Plug relay pigtail into relay, turn on headlight switch and flick on highbeams. If you did everything right the 4HI mod should now be complete.
Note: If you buy a 5 pin relay and pigtail (only 1 they had at NAPA), just pull the pin #87A wire from the center of the pigtail. There are 2 ways to remove it, either use a pick to push the little tab in or just pull really hard. Pulling really hard may break the tab on the female connector.
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