Blower motor constantly running

[msco123]

Ok, guys I have yet another question and beginning to think I an wearing out my welcome! Any just finished hooking of the AC controls and the blower fan runs with everything off(like its running on a very low setting.) When I turn the unit on everything seems to work fine except the fan will not run at all on the HI setting. So I guess you could say my fun runs all the time expect on HI.

[Mikedinva]

I'm no expert on the subject but to the best of my knowledge the fan is supposed to run on a very low setting all the time, there is no "off" Can't remember what GM called it, something like "flow thru ventilation" or "positive cabin ventilation". I bought my '77 442 new in April '77 and it has always been like that. It's not an A/C car though. My '76 442 is an A/C car and the fan runs all the time as well. I also have the "no hi" problem with it..... I've been told it is either a problem with the contact on the switch or that a previous owner replaced the blower fan with the wrong blower motor.

[rickman]

Mine always runs on low. For the "no hi" problem, check the inline fuse on the firewall and then the motor resistor switch in the heater housing. It has what looks like three springs on it, each a different size (resistors). Check the resistance on these if the fuse is OK.

[73CS]

The blower will run on low at all times when the car is running. The no high is most likely a fusable link or an in line fuse, I cant remember which, but I had to replace mine.

Blane

[58thndy]

If the blower's inline fuse checks out, it's probably the hi blower speed relay on the firewall.

You will probably find that you will destroy the inline fuse holder trying to get it apart to check the fuse. It's not "factory" but have a good inline fuse holder handy to replace it. Something with 10-12 gage wire and rated for 30 amps. NAPA or CarQuest will have them, and sometimes an Advance or AutoZone store will have heavy-duty ones.

[73CS]

If the blower's inline fuse checks out, it's probably the hi blower speed relay on the firewall.

You will probably find that you will destroy the inline fuse holder trying to get it apart to check the fuse. It's not "factory" but have a good inline fuse holder handy to replace it. Something with 10-12 gage wire and rated for 30 amps. NAPA or CarQuest will have them, and sometimes an Advance or AutoZone store will have heavy-duty ones.

Yep, now I remember, destroyed the fuse holder removing it. Replaced as mentioned above.

[Mike 77]

On The 77 with rear window defrost there is a hi fan motor cut out relay. If the defrost is on the fan can not run on hi speed. Too Much amperage draw. The relay is located on the fire wall. Check to make sure the relay is operating correctly.
Mike

[msco123]

Thanks, will check fuse and relay. Reason I was confused about the blower is it does not run on my other 73 so maybe that one has a problem too.

[73CS]

On The 77 with rear window defrost there is a hi fan motor cut out relay. If the defrost is on the fan can not run on hi speed. Too Much amperage draw. The relay is located on the fire wall. Check to make sure the relay is operating correctly.
Mike

73 is the same with the rear window defrost.

[msco123]

It was the fuse and you guys were right, it was a bear trying to get it loose.

[1977 Cutly]

Its good to know that my car is sposed to run the fan constantly. I installed a switch to turn it off. Now that I know that isn't a defect I might remove it.