rm4two

What's up guys. My 08 550 occasionally displays the yellow high temp warning message. I'm pretty sure the fan has shit the bed as it doesn't kick on at all. Regardless, I want to make sure and manually test the fan. How do I properly apply 12v directly to the Aux fan to test it? Btw, in case anyone was wondering, the warning message displays at 249 degrees fahrenheit.

e6t.lab.rat

Maybe a bad coolant temp sensor located on the lower radiator hose passenger side? This sensor triggers the fan to come on. Maybe others can chime in on testing the fan. Good luck

528canyonrot

I believe the aux fan will automatically come on if you turn on the a/c. Maybe you can use this to see if its coming on at all

rm4two

I'm going to replace that sensor tonight and see if that fixes it but, the fan does not come on when the A/C is on. In fact, it doesn't ever come on. That's how I know the warning message displays at that specific temp lol. I've checked all of the fuses behide the glove box and in the truck. The fan spins freely so i'm thinking it might be the relay as well? But we'll see after I install the sensor.

rm4two

So no one has manually tested there fan by applying 12v directly to it?

rm4two

Replaced the fan switch and still not working.