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Hello all, low mile untouched 82. My AC/heat blower motor isn't working and would like to track down the issue. I have built cars my whole life but always stayed away from the electrical side and let someone else handle that part... please keep this in mind if I ask an amateur question... this is what I think of when it comes to dash wiring.
I am assuming this is an issue beyond the switch as I have no blower on any speed, I can hear the click at the relay when I turn on blower to high and turn AC on so getting the signal at the under hood relay.
I removed the power purple wire from the blower motor and tested with a test light and get a very dim light... however I am showing 12v at that source
My question is... what's my next steps to narrow down the problem through process of elimination and again talk to me like I'm an idiot, I'm good with replacing the motor if thats the issues but its tight job on an 82 so want to be sure thats it.
Thanks guys... will track that down today, because the blower is not working on any speed I am assuming the only ground would be the one on the blower motor it self? Could this be why I'm showing 12v but it barely lights a test light?
I will get in there later his morning to track that ground
I don't know if/how '82 is different from '72 when it comes to the blower... On mine, there's a ground wire connected to a bare spade terminal under a mounting screw for the motor to the firewall and a single hot wire to the motor itself. Before going further, I'd test the motor using jumpers from a charged battery to both blower contacts. It's quite likely the ball bearings have gotten gummed up and won't let the shaft turn. (If this is the case, I'm a cheap SOB, so would remove the motor and use lube to free the bearings and regrease.)
I don't know if/how '82 is different from '72 when it comes to the blower... On mine, there's a ground wire connected to a bare spade terminal under a mounting screw for the motor to the firewall and a single hot wire to the motor itself. Before going further, I'd test the motor using jumpers from a charged battery to both blower contacts. It's quite likely the ball bearings have gotten gummed up and won't let the shaft turn. (If this is the case, I'm a cheap SOB, so would remove the motor and use lube to free the bearings and regrease.)
thanks... the 82 does have one power lead and one ground lead to the blower motor, I will track that ground.
So if I run power to the power lead and ground to the ground lead on the blower motor that will test the motor? Can I use a battery charger for this?
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Originally Posted by Golfobsessed
thanks... the 82 does have one power lead and one ground lead to the blower motor, I will track that ground.
So if I run power to the power lead and ground to the ground lead on the blower motor that will test the motor? Can I use a battery charger for this?
The other end of the black blower motor ground wire connects to a starter or bell housing bolt.
Disconnect the power lead and apply 12 volts from the battery to that terminal to see if the motor works.
The other end of the black blower motor ground wire connects to a starter or bell housing bolt.
Disconnect the power lead and apply 12 volts from the battery to that terminal to see if the motor works.
thank you... I purchased a GM service manual when I got the car but spent a few hours this morning looking for it, not sure where I placed it.
According to the test light i have good power going into to relay on the red/pink wire and blue wire... and the orange wire when fan speed turned to high as again I assume I'm good to there... I have no light on the purple wire which appears to go to the blower motor, would this indicate a bad relay?
I have no light on the test light at the power plug on the blower motor until I move to high speed then I get a very dim light
Last edited by Golfobsessed; Jun 7, 2025 at 01:33 PM.
Thinking its my relay
not sure I'm doing this right but put an OHM meter from the ground terminal on the relay to the power out to the blower motor and getting nothing
Last edited by Golfobsessed; Jun 7, 2025 at 01:49 PM.
Thanks all... got it, after seeing power coming into the relay but not out i assumed it has to be a bad relay... it was, I changed it and blower works well on all speeds.
no AC however, no power to the compressor so thats my next hunt, will eventually start a new thread, thanks again.
Thanks all... got it, after seeing power coming into the relay but not out i assumed it has to be a bad relay... it was, I changed it and blower works well on all speeds.
no AC however, no power to the compressor so thats my next hunt, will eventually start a new thread, thanks again.
compressor wont get an on signal if the pressure is too low in the lines.
Ah the relay I will have to remember that good find. Electrical items are not my strong point and I'm always trying to learn more and get better at it. Do you have the part # and where you picked that up , I may be needing one
Last edited by socal_tom; Jun 7, 2025 at 11:23 PM.
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
Something odd to me about the hookup location of the radio capacitor shown in the drawing Fig. 8A-39. If C104 is the 12VDC for the motor why is it shown going thru the capacitor in series. The capacitor would block the DC voltage....perhaps just an error on the drawing or am I missing something? Usually the radio capacitors go from a 12VDC connection to ground.
Edit Update: My car is the same way as in the drawing...suspect that this capacitor is internally wired different from the standard radio capacitor. Perhaps it passes the DC voltage connection as well as makes the capacitor connection from the power wire to its ground connection on the motor.
Last edited by Redvette2; Jun 18, 2025 at 01:46 PM.
compressor wont get an on signal if the pressure is too low in the lines.
yep thank you... I assumed its not coming on due to low pressure and will be where I start, I am going to start a new AC thread and beginning trouble shooting, I don't have the gauges to check pressure but will buy it, can I check for power at the pressure switch in the line?
Ah the relay I will have to remember that good find. Electrical items are not my strong point and I'm always trying to learn more and get better at it. Do you have the part # and where you picked that up , I may be needing one
frankly I just purchased one from a local auto parts store... it was cheap and fixed though I dont believe high quality... I will order a better quality one if needed just a quick fix yesterday, appears to be a common relay and plenty available
Something odd to me about the hookup location of the radio capacitor shown in the drawing Fig. 8A-39. If C104 is the 12VDC for the motor why is it shown going thru the capacitor in series. The capacitor would block the DC voltage....perhaps just an error on the drawing or am I missing something? Usually the radio capacitors go from a 12VDC connection to ground.
I don't have that in line radio capacitor on my 82.
I have the same problems with my 82 is the relay located on the passenger side of the firewall? I'm out of town atm so just trying to remember where I saw that relay...
Tracking down blower motor not working
