Cooling Fan Time Delay Module for HMMWV HUMVEE, 12338603

If the TDM burns out or loses power, it stops sending electricity to the Cadillac valve. Because the system defaults to "on," the fan will stay locked on 100% of the time from the second you start the truck.The Symptom: Your Humvee will sound like a jet airplane taking off, it will take a very long time to warm up, and you will notice a severe drop in fuel economy and power.

• The Symptom: The fan might cycle on and off randomly at incorrect temperatures, or the 20-second throttle-delay feature will completely stop working when you floor the pedal.

🛠️ The "Quick-Check" Diagnostic TestYou can test if the TDM is broken using a simple trick on the driver's side front area of the engine compartment:Start the engine while it is cool.Locate the TDM (small black box) and look for the two-wire harness connector running between the TDM and the gold Cadillac valve.Unplug the two-wire connector while the engine is idling.If the fan instantly engages with a massive blast of air, your fan clutch and Cadillac valve are working perfectly.Plug the connector back in.If you plug it back in on a cold engine and the fan fails to turn off, or if nothing happens at all, the Time Delay Module is dead and needs to be replaced.