Hi , is there any realy for elecrical radiator colling fan ? where
is it located ? i was told when a/c is turnedon the electrical
fan in front of the radiator should turn on, also when when
the engine gets hot. right ? on my car it won't turn on , however
when remove the plug to the radiator fan switch and jump the
wires it will comes on , is there any way to test the senser(fan
switch) ? any idia please let me know . thanks fred740il
Fred W - 12 Oct 2006 18:44 GMT
> Hi , is there any realy for elecrical radiator colling fan ? where
> is it located ? i was told when a/c is turnedon the electrical
[quoted text clipped - 3 lines]
> wires it will comes on , is there any way to test the senser(fan
> switch) ? any idia please let me know . thanks fred740il
Fred,
You have already diagnosed it pretty well. If you can remove the wires
to the temp sensor (it's a thermo-switch actually) and jumper them and
make the fan run, that means the problem is the thermo-switch. Good work!

Signature
-Fred W
fred740il - 13 Oct 2006 01:54 GMT
Fred W
, thanks for your reply , how can i test the termo switch
? at what temp the switch conects? can i poor hot boiling
water on the switch where it seats on the side of the radiator and
with a ohm meter( electrical tester ) see if the switch conects or
is there any other way to test , i konw i have already
tested that fan is ok , also why when i trun on the a/c the
cooling fan is not turning on , i don't thnik this opration (
turning the a/c on and radiator cooling fan is not working ) has
anythnig do with termo switch problem dose it ?? please advise .
thanks again Fred 740il
> > Hi , is there any realy for elecrical radiator colling fan ? where
> > is it located ? i was told when a/c is turnedon the electrical
[quoted text clipped - 9 lines]
> to the temp sensor (it's a thermo-switch actually) and jumper them and
> make the fan run, that means the problem is the thermo-switch. Good work!
R. Mark Clayton - 13 Oct 2006 01:25 GMT
> Hi , is there any realy for elecrical radiator colling fan ?
Yes.
> where is it located ?
Next to the radiator near the mechanical fan.
> i was told when a/c is turnedon the electrical
> fan in front of the radiator should turn on,
Not necessarily.
> also when when the engine gets hot. right ?
Yes.
> on my car it won't turn on , however
> when remove the plug to the radiator fan switch and jump the
> wires it will comes on , is there any way to test the senser(fan
> switch) ? any idia please let me know . thanks fred740il
You will need to get it pretty hot - try a hair dryer.
The electric fan will run if the car is idled for a long time in a very hot
place, especially if the AC is on (idle speed increased). On 7 series the
mechanical fan has a thermal viscous coupling on the main fan. This slips
when cold, so you warm up quicker and don't over cool the radiator in very
cold weather. It also stiffens up and increases cooling when it is very
hot.