WHY DOES My cooling fan run constantly on my 2001 Chevy venture?

Answer 1

Hi,

The first thing you want to check when the cooling fan is running all the time is the temperature gauge. If it is all the way at the bottom of its scale, even when the van is warmed up, you could have an error or diagnostic test code (DTC) set in the computer that is making the cooling fan run all the time. The code may NOT turn on the check engine light, but will cause the fans to run all the time.

That particular code would be a P0128, which means that the engine computer did not detect a change in the coolant temperature "fast enough" for what is expected. This could be caused by a variety of reasons, such as a thermostat that is stuck open (that's what I had in my van), a bad Engine Coolant Temperature (ECT) sensor, or bad or loose wiring between the engine computer and that sensor.

You can often check for codes (for free) by taking the van to an auto parts store and connecting their scan tool to the van. If you find that code (P0128), use the scan tool to clear that code and see if the temperature gauge goes back to a 'normal' reading. If that is the case, I would see about changing the thermostat, or having it changed (these are a pain to change in these vans).

Good Luck, Greg