radiator fan......ON......!!!

missfire · 30-01-10, 03:08 PM

hello,........

radiator fan .....on......all the time.....??? as soon as i connect the battery....?

disconnected the temp sensor on the rad...............ON.....

has anyone had this...?? wondered if it an 'open' or 'closed' circuit problem..?

thanks

Micky · 30-01-10, 03:13 PM

if you taken off the plug than it shouldn"t work

somewhere the wires are touching each other ?

missfire · 30-01-10, 03:19 PM

Quote:

Originally Posted by Micky

if you taken off the plug than it shouldn"t work

somewhere the wires are touching each other ?

will have a look for nasty insulation..........

could a state of 'low charge' in the battery cause any wierdness..???

new battery...not been for a decent run yet..

SteveCat · 30-01-10, 03:25 PM

djb1607 · 30-01-10, 03:57 PM

This has happened to me before. It was my Multi function sensor. Its on the coolant flange coming off the motor. It also ended up almost setting the relay on fire so be careful.

missfire · 30-01-10, 05:33 PM

Quote:

Originally Posted by djb1607

This has happened to me before. It was my Multi function sensor. Its on the coolant flange coming off the motor. It also ended up almost setting the relay on fire so be careful.

cool .....

thought that it was the culprit in a number of other issues..........so, i will take it out and carefully............smash it to bits...!

naffa · 30-01-10, 05:48 PM

This might be nonsense but couldn't it be the fan switch in the rad?

missfire · 30-01-10, 06:08 PM

Quote:

Originally Posted by naffa

This might be nonsense but couldn't it be the fan switch in the rad?

yup...this is what i meant by my first post....

on an audi 100.....

does the switch close to turn the fan on...?
or
does the switch open to turn the fan on...?

because i disconnected it, and the fan was still running..............

Woodsman · 01-02-10, 10:58 PM

Missfire, does the fan relay click when you connect the battery?
Does it still run if the relay is removed?

If no to both then most likely the relay contacts welded together.

If the relay does click then something is triggering it, MFTS, Fan after run relay, radiator switch, wiring short, etc.............
If it does still run with the relay removed then the motor feed is shorted to B+.

If the fan has more than one speed, then each speed will probably have a separate relay, Which speed is the fan running at when it shouldn't be?

I'm quite sure that most fan switches will be normally open (ie closed = fan on)

missfire · 01-02-10, 11:43 PM

Woodsman

i will check out the relay...pretty sure it is a single speed system but will make sure..!

it does not seem to be running very fast.....so if it is a 2 or 3 speed system, it is running on the 'lowest speed' setting,....all the time...!

weirdest thing was....i was out and fitted a new heater resistor pack into the blower motor housing.......no drama...(blower still does not work !!

blower motor works with a direct feed, so the controls must be nackered...

..) then went indoors for about an hour..

then let the dog out for a sniff around .........and the fan was running ...

and now it wont go off... so watever happened...it did so without the ignition switch on....

anyway...i will go for a snoop one day with a multi-meter....thanks

30-01-10, 03:25 PM	#4
SteveCat 4 ring whore! Classic Audi Club Member Join Date: Sep 2007 Posts: 3,523	. Nien __________________ Mercedes E220 Sportline Coupe

30-01-10, 05:48 PM	#7
naffa Vorsprung durch Technik! Classic Audi Club Member Join Date: Nov 2009 Location: Tipton, where where I kick ass. Posts: 564	This might be nonsense but couldn't it be the fan switch in the rad? __________________ Cheers Nathan

01-02-10, 11:43 PM	#10
missfire making wooden things Classic Audi Club Member Join Date: Dec 2009 Location: cow land Posts: 8,156	Woodsman i will check out the relay...pretty sure it is a single speed system but will make sure..! it does not seem to be running very fast.....so if it is a 2 or 3 speed system, it is running on the 'lowest speed' setting,....all the time...! weirdest thing was....i was out and fitted a new heater resistor pack into the blower motor housing.......no drama...(blower still does not work !! blower motor works with a direct feed, so the controls must be nackered.....) then went indoors for about an hour.. then let the dog out for a sniff around .........and the fan was running ... and now it wont go off... so watever happened...it did so without the ignition switch on.... anyway...i will go for a snoop one day with a multi-meter....thanks

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30-01-10, 03:13 PM	#2
Micky Mr Fifty Thousand! Classic Audi Club Member Join Date: Apr 2008 Location: Birmingham Posts: 8,738	if you taken off the plug than it shouldn"t work somewhere the wires are touching each other ?

30-01-10, 03:57 PM	#5
djb1607 Grown up member Join Date: Feb 2009 Location: Illinois, U.S. Posts: 193	This has happened to me before. It was my Multi function sensor. Its on the coolant flange coming off the motor. It also ended up almost setting the relay on fire so be careful.

01-02-10, 10:58 PM	#9
Woodsman Grown up member Join Date: Apr 2009 Posts: 92	Missfire, does the fan relay click when you connect the battery? Does it still run if the relay is removed? If no to both then most likely the relay contacts welded together. If the relay does click then something is triggering it, MFTS, Fan after run relay, radiator switch, wiring short, etc............. If it does still run with the relay removed then the motor feed is shorted to B+. If the fan has more than one speed, then each speed will probably have a separate relay, Which speed is the fan running at when it shouldn't be? I'm quite sure that most fan switches will be normally open (ie closed = fan on)