Review on Genuine GM Parts 15-81773 HVAC Blower Control Module by Victor Ceja

My 2007 GMC Envoy SLT with A/C had a bad fan motor (or so I thought). I dug into the fan module and fan motor under the glove box and put MM on both. the controller had 12.xx volts, the fan had 0 volts. I removed the glove box, fan module and the fan itself. Why the fan you ask when I just replaced the fan module? Because it is easier to route the power cable between the module and the fan when the fan is removed. Symptoms: The fan runs one day and not the next. When it worked it had 3 speeds. I connected DC clamps to the purple fan wire and got a maximum of 7.2 amps on the old module. With the new module installed I now get 8 speed boosters ranging from 1.57A to 14.80A. This is a great solution. The GMC dealership charged $265 for the part and $300 for the labor. It took me 1.5 hours. As everyone says you need to cut the old wire from the old module (3 wires) 2 18 gauge and 1 22 gauge. I used waterproof butt connectors. My advice: disconnect the negative battery terminal before you start! Tip #2: Use a multimeter to measure the resistance between the negative battery terminal and the vehicle's body ground. They should have less than 1 ohm resistance, preferably 0.5 or less. If you don't remove the chassis, ground and rub the connection and say you will. With this good chassis grounding, the fan motor will run at its highest possible speed.