2006 w211 e320 radiator fan not working - PeachParts Mercedes-Benz Forum

Phillytwotank · #1 05-07-2021, 05:48 PM

Hey y’all

I’m starting this new thread to see if anybody can help point me in the right direction on diagnosing this problem.

What I know: engine temp keeps going up and up and the fan never turns on.
The fan will turn on a slow speed when the AC is on.

There is no cel light or codes

That’s all I know

Any ideas or tips?

dieselbenz1 · #2 05-07-2021, 09:18 PM

Temperature sensor is bad.

Usaguy · #3 05-07-2021, 09:24 PM

Quote:

Originally Posted by dieselbenz1

Temperature sensor is bad.

Before Condemning the sensor I would take a look at the wiring diagram and start testing stuff.

You can usually find reference values for a temp sensor if you suspect that it's the cause of the problem

tjts1 · #4 05-07-2021, 09:28 PM

You need a proper scan tool to diagnose this. One that can turn out the fan in diagnostic mode and read codes from front SAM

Phillytwotank · #5 05-08-2021, 01:30 AM

I have icarsoft. Still learning it’s capabilites but I think it should be able to do that right ?

Phillytwotank · #6 05-08-2021, 05:43 PM

I pulled the plug on the temp sensor right on top of the thermostat housing. Jumped the terminals in the plug and the fan went to max.

BillGrissom · #7 05-09-2021, 11:48 AM

Quote:

Originally Posted by Phillytwotank

... fan went to max.

So your 2006 has a variable-speed radiator fan? Perhaps PWM control, which I understand are now common. My 2002 Chrysler has a PWM cabin fan, but the radiator fan is still controlled by an on-off relay (bolted to bumper). Replaced it recently, but couldn't tell if mechanical or transistorized.

dieselbenz1 · #8 05-10-2021, 10:13 AM

Quote:

Originally Posted by Phillytwotank

I pulled the plug on the temp sensor right on top of the thermostat housing. Jumped the terminals in the plug and the fan went to max.

Yikes let's us know how the new sensor works.