WelcomeCustomer I have looked at the schematic and if your fans are both working, try swapping the fan relay 2 with another relay in the block other than the fan relays. I will include the schematic below. Please ask if you need more information and let me know what you find.
Did you check the right and left IP fuse blocks? If there is none to try, I think you will have to buy one, unless you have another GM product. Other than that, you can use a scan tool to command the high speed fans on.
In heavy traffic, it might.
Ok. I will need you to use both. To start with, remove the fan relay 2 and 3, with the ignition on, check the terminals B1 B4 and C1 using the picture below. check that the terminals have power. Also check that the terminals are clean and not deformed.
The terminals will only have power with the ignition in the run position.
This is my part time job. I work full time at a GM shop
I do answer during the day. I get paid flat rate, so if I choose, I can answer some question. I was giving away my knowledge at GM Truck,.com, saw an ad and started doing this.