AC controller & blower motor questions

[webfoot]

Now that my 70 is driveable, the next thing will be to get the AC functioning. (probably just in time for winter.) I was just wondering about the AC controllers. What are the odds mine still functions OK? Is it better just to buy a repop, or an original GM, or a restored one?

Also, my blower motor works great on all settings but high. The fan speed switch is new. What else should I look at? Sounds to me like a ground issue, since high is a full 12v.

[Wrenchbender Ret]

You won't know about the controls till you try them. Often the cables get stuck. The levers break. All parts are available for them. They are not hard to o-haul. The high blower has its own fuse. It is in line near the junction block under the hood. Also there is a high blower relay mounted on the plenum under the hood. They are notorious for failing.

[jjzepplin]

My blower motor was doing the same thing and I found it was a bad ground at the motor.

[webfoot]

Originally Posted by Wrenchbender Ret

You won't know about the controls till you try them. Often the cables get stuck. The levers break. All parts are available for them. They are not hard to o-haul. The high blower has its own fuse. It is in line near the junction block under the hood. Also there is a high blower relay mounted on the plenum under the hood. They are notorious for failing.

Good info, thank you!

I will look for the relay but a lot of stuff got stripped away by a PO, so hopefully it is still there. I have a feeling it isn't, as I've not noticed any relays there. But, I can't even remember where they hid the horn relay on these things.

[hdff]

Originally Posted by Wrenchbender Ret

You won't know about the controls till you try them. Often the cables get stuck. The levers break. All parts are available for them. They are not hard to o-haul. The high blower has its own fuse. It is in line near the junction block under the hood. Also there is a high blower relay mounted on the plenum under the hood. They are notorious for failing.

What years had the in line fuse? I have no high speed fan, I replaced the high speed relay twice and neither worked, I had no fan at all so hooked my old one back and have everything except high. Just did a total referb of the system so I don't think I have a ground issue. Does a 71 have this fuse and if so where is it at specifically?

[webfoot]

I found a relay behind the vacuum pod on the passenger side, it was attached to the AC airbox. There was a ground attached to the mounting screw. Still need to track down that fuse.

Guessing new levers should be installed by default, and cables as well.

[jjzepplin]

Funny= I have a 72 and a 70. My 72 is the only one with Air but I have pulled and reworked both harnesses and don't know about this fuse either. If it is there I must have just replaced the fuse and kept on a wrapping those harnesses.

[ls1nova71]

Trucks don't have a fuse, but cars of this era did. The relays are know for going out because they're mounted upside down, and a leaky windshield (not that any of these trucks have that problem... ) will allow it to fill with water and rust it up. If a new high speed blower relay doesn't fix it, I have found a lot of times that it's the relay ground wire, that is just put under one of the relay mounting screws, often times won't be tight enough since taking the screws in and out of the fiberglass box takes the threads out of them. I usually lengthen the ground wire and bolt it to a solid metal ground.