30amp fuse for AC keep blowing

Greetings everyone… I’m exercising my Independence On 7-4-20… by chasing shorts!! I’ve been blessed with a 69 xr7 hard, w/ ac…all original. All AC components are in tact, but NOT connected. Just recently procured heater box With new everything (but not installed yet). My situation is the 30amp fuse for some strange reason trips. 1). Could it be because the complete system is NOT hooked up? Voltage drop? Resistance not present?

2). Upon removing dash…I found there’s a ground wire NOT landed (see photo) which is part of the harness attaching to climate control assembly :astonished:
Before i install Box and everything else…of course I’d like to find what is causing ONLY the 30 amp fuse to blow.

May I lean on any and all’s expertise in this manner? Thank you in advance

With everything disconnected, you’ve likely either got a connector pin touching ground or a short in the wiring harness. Check your connectors and then get the wiring diagram out and figure out and figure out what’s still in the circuit and use an ohm meter to check for grounds. Another possibility, did a prior owner alter or add to the circuit?


I just created a new thread to help folks find their shorts…


OK everybody greetings happy Wednesday. I have the AC heater box install …beautiful It sets well. The whole dash out lower and upper. Now my dilemma is as I put everything back together and order miscellaneous pieces. Is harness going to climate control see pic(Believe it is off of Harness 14 102) If anyone can tell me why I have the green ground which I don’t know what attaches to. And then on the other side of the harness there is no wire connected to the connecting pin. I thank any and all in advance

The two green wires attach to the icing switch. One is power, the other one goes to the AC compressor clutch. The other end of both wires clip to the fan switch (arrow). So in order to power the AC clutch the fan switch must be on and the icing switch must be closed (not too cold). Neither green wire is a ground.

Arrow pointing at the icing switch where that green wire connects. There should be a second green wire there that leads to the firewall. Both green wires plug onto the icing switch terminals.