With the recent discussion on dash electrical issues, the topic has come up about wiring in relays for headlights (for safety reasons).

I did this on my 66 GP a little while back, and Jmont64 asked me how I did it. I thought maybe I should post it on here in case others are interested. Keep in mind, I am NOT a mechanic and never claim to be an electrical guru but the lights all worked when I was done so it must be right!

Supplies needed-

2 Relays with pigtails.(I bought 40 amp relays.) Buy 'em anywhere, auto parts stores, Canadian Tire etc. My relays are 5 pin. You only need a 4 pin but 5 pin is more common. It works fine, one pin just doesn't get used. If you don't use it, remove the wire from the pigtail because the middle pin on the relay, which is the one you won't use (#87a) is live all the time as soon as you put the 12 volt power wire on the relay.

12 gauge wire. I think I used about 2 feet. It needs to run from the horn relay to the relays you are adding. On most 60's GM's, the horn relay is on the rad cradle, driver's side.

A terminal for the 12 gauge wire to connect to the horn relay.

Solder and heat shrink if you want to do this the proper way. I likely used about a foot or so of heat shrink.

Mount your relays as close to the horn relay and headlight wires as possible. I hung mine on the cradle above the horn relay.

To wire it up---

-Use a test light and find which wire from the dimmer switch feeds the low beams. Make a note of the colour. Now do the same for the high beams.

-Unhook the battery power to the car.

-Locate the big wire from the battery to the horn relay. It should be a heavy wire, likely red. Make sure there is a fusible link where it leaves the battery or you won't have any circuit protection for your headlights.

-Take the power wires that feed both relays (on my relay pigtail it was the red wire, it goes to #87 on the relay) and join them, then connect the joined wire to the same spot where the battery power goes to the horn relay.

-Take the power wires that exit both relays (on my relay pigtail it was the black wire, it goes to #85 on the relay) and join them, then connect the joined wire to a known good ground.

-Decide which relay is for the low beam. Locate the wire that runs from the dimmer switch to the low beam lights and snip it in the correct spot that it can reach the relay with both sides of the cut wire. After it's cut, the side that comes from the dimmer switch will connect to #86 on the relay. On my relay pigtail it was the yellow wire.

-Take the other side of that wire that you cut and connect it to #30 on the relay. On my relay pigtail that wire was blue. This is the wire that will feed power to your low beams.

-Now do the same for the high beams. On the other relay, connect the wire from the dimmer switch to #86 and the wire that feeds the high beams to #30.

Hook up the battery and test!