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This mod will allow you to keep BOTH high and low beams on when you switch your headlights to hi beam.:thumb:

You will need 2 relays, (you can actually use one, but 2 is a little less messy IMHO)40 AMP will be plenty. A hand full of female insulated spade connectors, zip ties and some red t-taps.

Each relay terminal is marked, 87,86,85,30 and 87a (which we will not use here)

Looking at the bottom part of the relay, where the terminals stick out you will see all of the terminals lined up in the same direction, except for 2. The one in the middle is terminal 87A, again for this application, we are going to ignore it, it will not be used.

Rotate the relay, so that the HORIZONTAL terminal is at the 12 o’clock position, this is terminal 87, moving CLOCKWISE the terminal numbers are 86-30-86. The hook up is easy, using one relay for each side, connect as follows:

87 to 12 volts constant

85 to ground

86 to the OEM headlight harness high beam wire

30 to the OEM headlight harness low beam wire.

You will need to do this for BOTH sides of the truck.

99-04 trucks: If you look at the OEM headlight plug there are three wires. If you are looking at the plug with the center wire at the 12 o’clock position, the wire on the right is low beam, the one on the left is high beam, and the one in the center is a ground.

Once you’re done, use the zip ties to clean up the wires, and make sure none of your connections are exposed.

No need to worry about blowing fuses, the relay(s) simply use the OE headlight power as a trigger, the actual power will come from your battery via the 12V source to the relay.
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