[mrein3]

I bought a used AC wiring harness when I did my non-AC to AC conversion. The plug for the fan speed switch was melted. I never even bothered to hook it up. I bought a new connector and a new switch.

Further I didn't bother to use the 30+ year old relay for high speed. I wired in my own relay and mounted it to the same screw.

I have a 10 gauge wire with its own fuse coming off the battery supplying a clean 12+ volts to the business end of the high-speed fan relay.

The only draw back is if I leave my set-up in the high speed fan position then try to turn off the truck. The HEI I installed gets a nice, clean 12 volts out of this circuit and keeps the truck running.

When I really get ahead of the game I'm going to install an extra fuse block to run all the things GM should have installed for me.

To make a long story short I'd look at that switch and connector. GM ran a lot of amps through that thing. After 30+ years and lots of furry connections you're going to get a lot of heat back there.

To prevent future melt-downs put in a new relay and run a seperate circuit. You'll never melt that connector again.

I have my headlight relay upgrade and hi-speed fan relay upgrade all running the same relay. I only need to keep one spare in the glove box.