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tucsonjwt · 06-10-2011, 11:30 AM

The stock blower motor has always worked fine on my 73 (no a/c) and 76 and 82 with a/c. Having owned many new GM trucks and SUVs in the past 10 years, I can say that newer blower motors push slightly more air on the highest speeds and do have more settings, but they are not noticeably more powerful on the highest speed than an old square motor. Are your sure that your fan switch is actually changing the fan speeds when you move the switch on the a/c control? I had my fan switch go out and the higher fan settings were not working even though the lever was moving through all of the positions. I also had the fan switch harness dry out and make poor contact (common in hot desert climates), which caused the fan not to get the high speed signal from the fan switch. I would make sure that you can hear and feel changes in the flow of air when you move the fan from low to high setting - my vote is for the fan switch or harness, but I have gone through all of the other suggestions noted above. Good Luck.

06-10-2011, 11:30 AM	#11
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,188	Re: Upgraded blower motor The stock blower motor has always worked fine on my 73 (no a/c) and 76 and 82 with a/c. Having owned many new GM trucks and SUVs in the past 10 years, I can say that newer blower motors push slightly more air on the highest speeds and do have more settings, but they are not noticeably more powerful on the highest speed than an old square motor. Are your sure that your fan switch is actually changing the fan speeds when you move the switch on the a/c control? I had my fan switch go out and the higher fan settings were not working even though the lever was moving through all of the positions. I also had the fan switch harness dry out and make poor contact (common in hot desert climates), which caused the fan not to get the high speed signal from the fan switch. I would make sure that you can hear and feel changes in the flow of air when you move the fan from low to high setting - my vote is for the fan switch or harness, but I have gone through all of the other suggestions noted above. Good Luck.