why are aux. radiator fans not coming on?

Here I am again! My two small front aux. radiator fans are not turning on and Im running hot because of it. Anyone know what activates these so I can fix it? Thanks

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Well, there's a thermostat, a fuse and probably a relay. Take your pick of which of these is not working as it should.
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Also check if the fans rotate easily. On my 190E 2.6 the high speed fan froze and blew the fuse. Peter

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and thermoswitch.
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Also, don't know where you're located, but in most cars, its unusual for the aux electric fan to come on unless it's very hot outside and/or the car is stationary or in slow moving traffic. Normally the regular fan should provide adequate cooling. I had a problem once on my 300SD and part of the circuit was turned on by the A/C being on and the refrigerant temp at the radiator being over a certain temp. It was controlled by a relay. There's probably another part to the circuit that turns it on if the coolant gets too hot too.
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"Tiger1" wrote: > and thermoswitch.
Thanks guys! I appreciate the help.
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On Thu, 05 May 2005 19:51:21 -0700, "T.G. Lambach"

an an electric motor
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"Vlad4" wrote: > On Thu, 05 May 2005 19:51:21 -0700, "T.G. Lambach"
> > >Well, there's a thermostat, a fuse and probably a relay. > >Take your pick of which of these is not working as it should. > > an an electric motor
Thanks for all the help on this one guys. I changed my temp control sensor and tested for current; the motor temp was checked and turned out to be o.k. A/C wouldnt kick on fans because there was not enough pressure in system to activate it. Turns out there is a bad connection in the cluster and temp is reading erradic.
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Because your auxillary fan clutch is shot. P.

http://www.autoforumz.com/Mercedes-Benz-aux-radiator-fans-coming-ftopict118852.html
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