Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
Hi, the first thing you need to do is test for power to the fan. If you have no power to the fan you probably have a bad fan control module. Fuse 38 powers the module. Check the fuse first. If the fuse is good and there is no power to the fan your module will most likely need to be replaced.
Let me know if you have any questions.
Can you post the last 8 digits of the vin number?
How did you come up with those codes?
421 and 422 are fault codes for the auxiliary fan and the serial communication from the climate control module. Do you have power to the red/white wire at the fan module? If you do, I would question whether your used module is any good.
The red/white wire comes out of the left front SAM. You need to go to trace the wire back to the SAM and see if you have voltage.
Is fuse 41 installed? Is there power to fuse 41?
Are you sure you are checking the correct wire at the SAM? If you use your power probe to put power to the red/white wire at the SAM do you get power at the module?
Is it the original a/c control head? Have you checked the coding of the head?
Key off - press and hold REST button - turn the key on - release the REST button - read the coding on the display.
00 is probably correct. Try changing the coding to 02 and see if it works. Then try 10, 18 and 32. It sounds like the a/c control head may be bad. Have you already replaced it?
It looks like the data flows from the N22 to the instrument cluster. I'd check the wiring from the N22 to the cluster. The blue/yellow wire from the N22 goes to the cluster.
Yes that is the wire.
Are you able to check the coding of the instrument cluster?