Blower motor - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jered1987 · 12-01-2018, 04:02 PM

I’m wondering where to start
When I took my truck out back a few months ago
I had to use the defrost and the blower was working so slow
I had to keep the windows up just to keep the windshield from fogging up.
I can turn it to whatever and it barely is running all you hear is it barely running and squeaking.

**dmjlambert** · 12-02-2018, 01:14 AM

The last time I had that happening, I removed the blower motor and used jumper cables to connect it directly to the battery to test that it worked OK. It did not work OK so I went up to O'Reilly and got a new blower motor.

I believe the auto parts stores only carry the A/C blower motor, and not the heater-only blower motor. So if you have a heater-only truck it may be best to look online and see what you can find for a blower motor. There is not a lot of information about this online for some reason. Here is an old post with some info, including from GMCPaul. http://67-72chevytrucks.com/vboard/s...ad.php?t=76855 Back when this was originally posted GMCPaul said he stocks both types of motors, A/C and heater.

The AC blower motor draws much more current at high speed compared to the heater blower, so the factory A/C wiring includes a relay to operate the fan on high, so too much current doesn't go through your fan switch and burn it up. If you have a look at the wiring for the A/C in the service manual, you'll see how they dealt with the fan wiring and relay, and the fuse is 25A instead of 10A. The electricity when the blower is on high goes from the CIG connector on the fuse panel, which is always on unswitched and unfused power, through a 12 gauge orange wire through the relay, and to the blower motor. To run an A/C blower motor in a heat-only truck you could probably add a relay to provide that amount of power to the blower when it is on high.

Here is another thread on the subject, with the service manual page that I posted with the electric diagram.
http://67-72chevytrucks.com/vboard/s...d.php?t=727010

Andy4639 · 12-02-2018, 01:22 PM

It could be several things. Mice and what not they have filled the heater box up with nesting crap and have the heater motor bogged down.
Could be the motor it's self. Quick check is take the lead off the motor and jumper it out to the battery + terminal. If it blows hard then it could be in the levers not adjusted right are the fan switch is bad.

12-01-2018, 04:02 PM	#1
Jered1987 Registered User Join Date: Aug 2017 Location: Calhoun,ga Posts: 139	Blower motor I’m wondering where to start When I took my truck out back a few months ago I had to use the defrost and the blower was working so slow I had to keep the windows up just to keep the windshield from fogging up. I can turn it to whatever and it barely is running all you hear is it barely running and squeaking.

12-02-2018, 01:14 AM	#2
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,562	Re: Blower motor The last time I had that happening, I removed the blower motor and used jumper cables to connect it directly to the battery to test that it worked OK. It did not work OK so I went up to O'Reilly and got a new blower motor. I believe the auto parts stores only carry the A/C blower motor, and not the heater-only blower motor. So if you have a heater-only truck it may be best to look online and see what you can find for a blower motor. There is not a lot of information about this online for some reason. Here is an old post with some info, including from GMCPaul. http://67-72chevytrucks.com/vboard/s...ad.php?t=76855 Back when this was originally posted GMCPaul said he stocks both types of motors, A/C and heater. The AC blower motor draws much more current at high speed compared to the heater blower, so the factory A/C wiring includes a relay to operate the fan on high, so too much current doesn't go through your fan switch and burn it up. If you have a look at the wiring for the A/C in the service manual, you'll see how they dealt with the fan wiring and relay, and the fuse is 25A instead of 10A. The electricity when the blower is on high goes from the CIG connector on the fuse panel, which is always on unswitched and unfused power, through a 12 gauge orange wire through the relay, and to the blower motor. To run an A/C blower motor in a heat-only truck you could probably add a relay to provide that amount of power to the blower when it is on high. Here is another thread on the subject, with the service manual page that I posted with the electric diagram. http://67-72chevytrucks.com/vboard/s...d.php?t=727010 Last edited by dmjlambert; 12-02-2018 at 01:23 AM. Reason: add more info

12-02-2018, 01:22 PM	#3
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,936	Re: Blower motor It could be several things. Mice and what not they have filled the heater box up with nesting crap and have the heater motor bogged down. Could be the motor it's self. Quick check is take the lead off the motor and jumper it out to the battery + terminal. If it blows hard then it could be in the levers not adjusted right are the fan switch is bad. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.



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