The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - '72 Factory AC

ssuesens · 05-13-2023, 08:14 PM

The heat/AC fan on my '72 C10 only blows low and medium. After searching this site, i found a couple threads that said to replace the relay under the glove box. I did that today ($19 from O'Reillys) and still no Hi speed on the fan. When I move the switch from Med to high, I do hear a click in the relay. I believe that the resistor controls fan speed on low & medium, and is bypassed completely for high speed. Not sure where to go from here.

05-13-2023, 08:14 PM	#1
ssuesens Registered User Join Date: Nov 2013 Location: Keller, TX (DFW) Posts: 45	'72 Factory AC - No 'hi speed' on fan The heat/AC fan on my '72 C10 only blows low and medium. After searching this site, i found a couple threads that said to replace the relay under the glove box. I did that today ($19 from O'Reillys) and still no Hi speed on the fan. When I move the switch from Med to high, I do hear a click in the relay. I believe that the resistor controls fan speed on low & medium, and is bypassed completely for high speed. Not sure where to go from here. __________________ "Life is too short to use cheap zip ties" 64 C10 SWB 71 C10 LWB 72 C10 LWB