Rear AC relay?

[iriereggaeman]

Hi folks,

After poking around for a bit, I was unable to find what I was looking for, so starting a new thread.

My Rear AC works for low and medium, but not high. Front AC works for Low, Medium, and (now) High - since I replaced the relay (see http://67-72chevytrucks.com/vboard/s...64&postcount=3 ). Folks on the forum helped me find it behind the glove box.

Anyone know if perhaps the rear AC also has a relay, possibly hidden somewhere equally fun?

Thanks,
-Greg/IrieReggaeMan

[iriereggaeman]

not many folks with rear air-conditioners, I'm guessing? I'm on my second rear-AC switch with the same behavior, so looking for other reasons why HIGH doesn't work.

Thanks!

[LockDoc]

Originally Posted by iriereggaeman

not many folks with rear air-conditioners, I'm guessing? I'm on my second rear-AC switch with the same behavior, so looking for other reasons why HIGH doesn't work.

Thanks!

I have a rear AC setup out in the barn I can look at but it is raining cats & dogs right now so it won't happen until it lets up some....

LockDoc

[LockDoc]

-
There is both a relay and a resistor (on the same order as the heater resistor) on the inside of the rear housing. I'm betting one of those is the culprit. I would visibly check the resistor first to see if any of the coils are broken or touching each other......

LockDoc

[iriereggaeman]

Thanks LockDoc! I'll give that a check.

[iriereggaeman]

ok, so it took me a while to get back to this. Life gets in the way of non-essential old truck fixes.

Review: I'm trying to get my rear AC to run on high. Low and Medium settings work just fine.

I popped of the rear AC housing. I looked at the resistor, as suggested by LockDoc. A rough glance, I don't see any obvious failures. Here are a couple pics:










and a short video:
https://youtu.be/PXq9Dhlf2ZY

The resistor has labeled INDAK 3929051. I see available resistors for sale labeled INDAK 3929055. I wonder if they are the same, or close enough.

Anyone have any ideas what to try next? Is my relay perhaps located somewhere else? Generally the relay should be near the thing it controls, so I would guess it's nearby. I didn't take apart the motor housing...perhaps it's in there?

[iriereggaeman]

thanks HO455 and LockDoc. I'll test out the resistance of the two coils. I'll see if I can trace the wiring from the resistors as well to possibly find the elusive relay. I have an all-inclusive manual 67-72 Haynes manual I'll look at too for inspiration.
At the moment I'm installing power locks from A1 Electric, and have the usual stumblings with running wires around the whole rig. Maybe I'll get lucky and run into the relay during that!

[Bigdav160]

"High" will never run through the resistor as the fan motor gets full 12 volts on high speed.

I don't remember a relay for the rear unit. That would mean all the power goes through the switch. Not good for the switch and probably should be on a relay