GMC Headlight Relay Mod

[VetteVet]

Here's the circuit diagram to install the GMC relays.

You'll have a brown wire and a green wire coming from the dimmer to the relays to terminal 86 on each relay and there will be three wires for the dim lights and four green wires for the brights.




It should be simple to wire in the relays. Just cut the brown and green wires from the dimmer before they get to the headlights and wire them to the 86 terminals on the respective relays, then wire the other side of the cut wires to the
87 terminals on the respective relays. That should complete the circuits to the four headlights. Then You just have to run the power wires to the no. 30 terminal on the relays, fused as shown, then connect the grounds to the 85 terminals.