I was sitting in parking lot on a hot day, waiting for wife, with the air running and Temp goes up to mark passed 100. I figure its a good time to check to see if Aux, fans are running. Their not!! Should they be?. I have never seen or heard them run. Would this show up on computer read out? It never has. Does anyone know a simple check? Any help would be appreciated

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1998 E300Turbodiesel
1980 300d

Ready- Ronnie

There is a test, I don't recall what it is but it involves pushing some buttons on the ACC panel. I can tell you that if yours didn't run under those conditions there is a problem. You can find the plug for the motor under the little cover up front on the right side and try and jumper 12V to the motor directly and test it that way...I'd bet the motor is DOA - it was on mine.

Replacement is easy and intuitive. You can buy just the motor side with fan and don't have to buy the entire assembly with the "slave" fan and frame (I know that slave isn't the PC term but that is what it is called). That will save you some money. I recommend replacing the belt too though if you go that route.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

With the key in position 2, press and hold both AUTO buttons for >10 seconds to start the fan test.

Pressing both AUTO buttons for >10 seconds again or turning the key to position 0 (1?) cancels the test.