Thunderwagon, I might be interested in seeing if we can work a deal since you're local to me. Greenlee, thank you for the offer too.
Today was headlight relay mod day.
I showed a picture above of a relay pack I had scavenged from some junk car in the past. I wasn't happy with their condition though, so I dug through my stock of relays. Mind you, I'm the guy that won't turn down the opportunity to scavenge over a junk car, so I tend to collect things like this. I found a box of very nice Nissan relays I had saved that looked promising.
The blue ones have the proper configuration that I need. Plus, they're good quality Jaoanese made units, which I'm confident are better than typical Chinese 5 dollar relays.
Now, let's talk theory here. I said they had the right configuration for my needs. Notice the diagram on the top of them. Terminals one and two are the latch circuit and terminals three and five are the load circuit. What this means is that when you supply power to terminal one, it flows through the relay to ground, and activates the circuit. When it is activated (terminal 1 powered), terminals 3 and 5 connect. When terminal 1 doesn't have power, the latch circuit opens and terminals 3 and 5 are not connected. That's what we need.
I was fortunate that a few years ago someone gave me a very high quality bench type of power supply. It plugs into 110v and supplies a steady 12 volts. Using this I could use jump wires and my multimeter and test the relays to make sure they work.
The downside to using these OEM Asian relays is difficulty mounting them. The common generic relays have a nice little screw tab on them to facilitate mounting. These obviously did not.
So, I dug around my shop and turned up something I could work with.
Using a Dremel and files I cut into it, leaving two tabs that slid into the little bracket grooves on the back of the relays.
I also needed a circuit breaker and some green and brown wire to build new headlight harnesses. Fortunately GM has used green/brown/black for headlight circuits forever. I know my 63 truck used the exact same format as this truck does.
I've found my local trailer supply place is cheapest for this stuff. They have the circuit breakers for 4 dollars. I chose a 20 amp auto reset breaker. Using Ohms law, we can calculate what is appropriate for our needs. Each headlight is 65 watts. Two headlights totals 130 watts. Divide 130 watts by 12 volts and you find that the headlights will draw 10.83 amps. I chose a 20 amp breaker. To get the wire I needed, I bought a 20 foot trailer wiring harness for 4 dollars. That gets me a ton of the proper color wire for dirt cheap. Sure beats buying it by the spool at the local auto supply store. Anyway, 9.63 total out the door.
Circuit breaker mounted inside the passenger fender, near the battery. Always mount your circuit protection device as close as reasonably possible to the power source. I'll be using 12 gauge wire to power the headlights.
Power from the battery comes into the copper colored stud (its important, and the breaker is appropriately labeled as such) then leaves the breaker via the other stud and passes over to the relays where it splits off to each one.
All new wiring in appropriate colors run across the front of the truck. The stock headlight power wires from the switch were terminated into each relay to act as a trigger source. The little ground wire you see there is the ground for the latch circuit. The big black wire is the 12ga power from the circuit breaker. It runs to the first relay and jumps across to the second one in parallel so each realy has a heavy gauge power feed to give to the headlight bulbs.
Here you can see the driver side headlight wiring specifically. Notice each headlight has its own dedicated black ground wire which I terminated to the core support individually.
That's it. Done deal.