C230 W202 Auxilary Fan Difficulty

[GLE041]

I have a 1997 C230 W202 Mercedes-Benz.

I noticed awhile ago that my auxiliary fan is constantly running at what seems to be its highest speed. It kicks in right after I turn the car on, and does not turn off or slow down at all.

I brought it to a Mercedes Mechanic (non-MB dealer) who took 3 days to find the problem. He said the fuses, relays, and sensors are all okay. He thought it was the pressure switch, but after replacing that the fan was still on so they kept searching.

Today I was told the problem is a short circuit in the digital climate control unit and told it needs to be replaced. Could this cause the problem?

I have found an exact model number match part on eBay I am looking to purchase and install. Are the climate control units simple plug and play?

Thanks in advanced for all your help.