1989 300E Temperature Sensor
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Joined: May 2004
Posts: 261
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From: Atlanta
1983 240D, 1989 300E
1989 300E Temperature Sensor
So my aux fan doesn't work and I am doing some trouble shooting. I first connected the fan directly to 12V and it spun. So next after searching threads I heard of the temp sensor. I want to make sure this is the temp sensor before I try to jump it. The plug in green in the middle of both pictures. Now if this is the right plug, I should be able to jump the two prongs and the fan should work correct? If the fan doesn't come on then it would have to be the fuse or relay correct?
TIA for all help.
TIA for all help.
Last edited by LoveLEE143; May 11, 2007 at 12:26 AM.
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Joined: Oct 2006
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'87 260E
The temp sensor is mounted on the cylinder head, beside the elbow hose on the 2nd picture. I think OE plug is gray with 3 terminals. You can jump & ground the wires to check if the sensor is still working. The aux fan fuse terminal unfortunately melts after so many years of service. Fix is to install an auxillary fuse box with a strip fuse.
Thread Starter
Senior Member
Joined: May 2004
Posts: 261
Likes: 1
From: Atlanta
1983 240D, 1989 300E
Sitting in traffic the temp will rise as high as I let it go. If I have to sit in trqaffic and i see the temp rising I turn on the heat. I know the fan doesn't run because I have let it get very hot sitting still and no fan. I am going to flush the coolant today. And fix the AC this weekend. They don't call it HOTlanata for nothing.
