Radiator Fan always on even at startup
Thread Starter
Newbie
Joined: Apr 2025
Posts: 4
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2006 C55 AMG
Radiator Fan always on even at startup
My radiator fan turns on a stays on 1 minute after I start the car. When the engine is warmed up my temp is normal at 185. I know the AC is not running because I put my pressure gauges on it and see the compressor does not kick in until I press the A/C button. These are 2 speed fans and it runs on the lower speed.
One thing I noticed is when I was working on the Radio I started the car with the HVAC controls unplugged, the fans never turned on. Don’t know if that is a clue or not.
Thanks.
One thing I noticed is when I was working on the Radio I started the car with the HVAC controls unplugged, the fans never turned on. Don’t know if that is a clue or not.
Thanks.
Thread Starter
Newbie
Joined: Apr 2025
Posts: 4
Likes: 0
2006 C55 AMG
I fixed it,
Turns out the connector for the A/C high pressure switch had broken wires, One with was broken off another was ready to do the same. On this car the HPCO is on the bottom of the condenser next to the receiver/drier. A vulnerable spot since there is only a plastic cover protecting it.
Had to visit the boneyard and harvest another connector. Then had to disassemble both connectors and use the wires. Had to solder and heat shrink tubing the connections.
Now the fan turns on only when it needs to and when you turn on the AC.
Turns out the connector for the A/C high pressure switch had broken wires, One with was broken off another was ready to do the same. On this car the HPCO is on the bottom of the condenser next to the receiver/drier. A vulnerable spot since there is only a plastic cover protecting it.
Had to visit the boneyard and harvest another connector. Then had to disassemble both connectors and use the wires. Had to solder and heat shrink tubing the connections.
Now the fan turns on only when it needs to and when you turn on the AC.
