My AC was blowing this morning, now it's not.
How can I tell if it is a switch or if it is the fan? Which switched do I check?

Thanks!

Signed,
Hot & Sweaty in AZ....

1st of all check the fuse in the fuse block on the lower drivers side of the car.  What does that tell you?

Got further under the hood today and it looks/sounds like the blower motor went bad. It has a quiet grinding sound, but still lightly blows. I will get a replacement motor ordered tomorrow and get to work.

  New question: Any tricks and tips to replacing the blower fan motor? It doesn't look easy, but the accumulator replacement I just did last month wasn't easy either. I have all the shop/service manuals and will be reading up.
It just couldn't wait until winter

Thanks!
 

The high speed blower, and all the other speeds, work off of different circuits, so it's possible to have NO high speed, but all the other speeds, as is it possible to have only high speed, but no other speeds.
The blower motor should be running any time the key is on, on LOW speed, so...what you're hearing may be just the normal, low speed of the blower.
What does it do if you try the other speeds? Does the sound change any at all? If it does, then the switch is prolly otay, and the blower motor is prolly toast. If it doesn't, then you may need to do some testing. First, tho, make sure the ground wire that is screwed in with one of the blower motor bolts is nice and tight...that wire can get loose, and cause the same sympthoms....
You can run a jumper wire to the motor with 12v, and it should spin like it does with the switch on 'High". If it don't, then the motor is definitely bad.

As far as changing the blower motor, it's not exactly the most fun job, but it beats the h ell out of working under the dash! You may need to move some stuff out of the way to get the motor all the way out past the fender, like the coolant bottle, and you may find that your hands/arms don't bend the way you need them to, to get to the bolts...

  I removed the motor and fan impeller and the problem was the nut holding the impeller to the motor shaft was MIA. This was causing the impeller to bounce and rub in the housing. Everything went back together good and tight, including the impeller; I used a drop of thread lock so it should never come off the shaft. 
FYI: Motor was accessible buy taking off the right side fender vent, coolant tank and compressor mount bolts - STILL easier than under dash work!! 

Joel,
I installed a new speed switch last year because I had no low speeds - only high speed. The switch was not the problem as I still have only high speed. What would be the cause of this and what should I check?

Thanks for the help!



Phill's Vette2009-08-10 20:28:41

No low/med/med-high speed is normally caused by a bad resistor, if the switch is good, and there is power to it. The resistor coils are usually inside the evaporator box/housing, under the hood. They have a tendency to get corroded, and not make good contact with the crimped connections on the ends of the coils. Ya might pull that out and have a look-see. Look for a small, rectangular shaped block with a wiring connector on it, normally pointing straight down, in the top of the evaporator housing. I think there was some pics posted in another thread a while back.

The high speed blower is on a separate circuit, and runs thru a relay, which is why you can have some speeds working, and not others.

Phill, I had similar problems a year or so back. In the fan circuit there is a RELAY that is mounted on the firewall and on your 82 is attached to the plastic wiring harness cover on the passengers side of the distributor.  This relay on mine was not working correctly.  I removed the relay cover and used fine abrasive paper to clean the contacts, and its worked great ever since.  The solderless connectors on the RESISTOR are bad to get corroded as well, give them the wiggle test to see if that may be  your problem.

Same here; only the high speed was not working.  When I removed the cover of the relay; they whole thing fell apart; it was cracked in half (the bottom being plastic I guess).  Those relay are not cheap if my memory serves me right.

Anyway, I still don't have A/C, but I fixed the problem by driving faster and without the tops!

Thanks for the links Chip! I think I will go ahead and order the relay and resister - might as well as I have invested this deep into the AC already.

  I tried the high speed without tops and all I got was $580 in excessive speed acknowledgments from the Arizona highway patrol......