Audi 100 c4 electric engine fan not working

Malbec · 11-06-13, 04:14 PM

Hi all,

Been a member here for about a month and enjoyed reading. I have a 1991 audi 100 2.3 c4 auto. I want to make this car my daily driver as it is in good condition and I believe (hope/pray) that these are reliable cars.

Recently my electric rad cooling fan has stopped working. My car has a main fan which is viscous, so that works, but the electric fan does not cut in, even when temp gets to over 110c. It used too, but has suddenly stopped working. I have removed the fan and discovered it works from a battery and that there is no current from the supply lead. I have checked the fuse in the dash side, all ok. But I believe there is another fuse under teh dash, but I cannot find it? Hope someone can help, I am due to go on a long journey in this car soon, so i need he fan working.

Cheers,

John

maxustaxus · 12-06-13, 10:04 AM

Hello John...(congrats on your first post?)

I am afraid I don't know anything about this system...or how to locate fuses, but the following link might be useful. Especially stuff about testing coolant temperature sensors within the system (which might be relevant if you haven't already ruled this out).

http://www.sjmautotechnik.com/troubl...g/cooling.html

Best of luck with it anyway.

Malbec · 12-06-13, 10:25 AM

Quote:

Originally Posted by maxustaxus

Hello John...(congrats on your first post?)

I am afraid I don't know anything about this system...or how to locate fuses, but the following link might be useful. Especially stuff about testing coolant temperature sensors within the system (which might be relevant if you haven't already ruled this out).

http://www.sjmautotechnik.com/troubl...g/cooling.html

Best of luck with it anyway.

Hi maxustaxus,

Thanks for replying. That is a good link, I have been there already and found that there description of the MTFS sensor matches mine, whilst the Haynes manual and the ElsaWin I have do not, so it is a useful site.

I am still struggling to work out where the power for my electric rad fan comes from. I think I will end up wiring a power direct from the battery to get it to work. which is a bodge and i would rather not do this, but I don't know what else to do as the car over-heats without the elec fan.

Cheers, John

missfire · 12-06-13, 09:26 PM

Hi, I don't know this model, the two fan thing must be a fancy auto C4 thing!

On mine the big switch on the radiator operates a relay in the fusebox I think. Have you tried pulling the wires off of the rad. switch and putting a jumper between them? (with your finger well clear of the blades!

)

Malbec · 13-06-13, 01:38 AM

Hi Missfire, my car has a main viscous fan and a separate electric fan that should kick in about 98deg I think. There is no temp switch on the rad, the fan gets its signal to come on from either the dash or the multi function switch on the coolant pipe out of the engine block, not sure which. Basically, the car gets to just over 110deg and the fan does not come on. So I tested the motor and that works, but there is no current to the supply wire. I checked the fuse box all ok and relay. But apparently there is another fuse somewhere under the dash, but I cannot find it and I cannot find anything about the fan on ElsaWin either! Any ideas?

Malbec · 13-06-13, 09:59 AM

Help needed urgently please?

Ok, I just cannot find why there is no power to my fan. I badly need to get the car working now, as I have a long journey planned for saturday. So was wondering is there any reason why I should not run a length of wire direct from the + post on the battery, through a fuse, then a thermo switch to the fan, to get it to work that way? If so, what sort of amp wire do I need and what fuse would I fit, is this safe I don't want to start a fire or ruin my electrics obviously.

Hope someone can give me some help with this.

msh · 13-06-13, 04:49 PM

Quote:

Originally Posted by Malbec

There is no temp switch on the rad, the fan gets its signal to come on from either the dash or the multi function switch on the coolant pipe out of the engine block, not sure which.

That's bullshit, where did you got that from? Thermoswitch is on the left side [passenger side in UK] of radiator.

Malbec · 13-06-13, 07:35 PM

Quote:

Originally Posted by msh

That's bullshit, where did you got that from? Thermoswitch is on the left side [passenger side in UK] of radiator.

Charming!

There is no switch on my rad at all! It has a blanking plug where one is fitted on most models. My particular car a 2.3e auto without aircon, does not have that switch in the rad, it uses a signal from I think the dash that comes via the MTFS switch.

There is certainly NO switch of any kind on the rad, not Bull*shit, just fact you are wrong. Are you always this aggressive to new forum members who ask for help?

msh · 13-06-13, 07:50 PM

If you consider that agressive, sorry, that's not my intention. In any case it's strange to read such a sure assumptions which goes against both schematics and ETKA [the official electronic spare parts catalog]. After all, you have 1991 A100 with 2.3 engine, which is rather simple. The only old audi using something like your imaginations is audi V8, which, as a luxury car, employs not one or two speed thermoswitch like the rest of audi range, but three speed fans, turned on by some bit of electronics embedded in instrument cluster, using info from coolant temp sender in flange and, yes, in radiator.

In your case, if there really is no thermoswitch in your radiator, it's time to get one and find the connector left from previous one.

Audi Derek · 13-06-13, 07:55 PM

Why not just put a switch in the car for the fan run a wire in (earth) to the switch then wire up an relay close to the fan and you can switch it on and off as and when..

..

12-06-13, 09:26 PM	#4
missfire making wooden things Classic Audi Club Member Join Date: Dec 2009 Location: cow land Posts: 8,156	Hi, I don't know this model, the two fan thing must be a fancy auto C4 thing! On mine the big switch on the radiator operates a relay in the fusebox I think. Have you tried pulling the wires off of the rad. switch and putting a jumper between them? (with your finger well clear of the blades!)

13-06-13, 07:55 PM	#10
Audi Derek “Been raced and rallied” Classic Audi Club Member Join Date: May 2008 Location: Bridgwater Somerset Posts: 1,431	Why not just put a switch in the car for the fan run a wire in (earth) to the switch then wire up an relay close to the fan and you can switch it on and off as and when.. .. __________________ Vorspurng durch Technik (see it does work)

12-06-13, 10:04 AM	#2
maxustaxus Grown up member Join Date: Mar 2010 Posts: 198	Hello John...(congrats on your first post?) I am afraid I don't know anything about this system...or how to locate fuses, but the following link might be useful. Especially stuff about testing coolant temperature sensors within the system (which might be relevant if you haven't already ruled this out). http://www.sjmautotechnik.com/troubl...g/cooling.html Best of luck with it anyway.

13-06-13, 01:38 AM	#5
Malbec Grown up member Join Date: Jan 2013 Posts: 39	Hi Missfire, my car has a main viscous fan and a separate electric fan that should kick in about 98deg I think. There is no temp switch on the rad, the fan gets its signal to come on from either the dash or the multi function switch on the coolant pipe out of the engine block, not sure which. Basically, the car gets to just over 110deg and the fan does not come on. So I tested the motor and that works, but there is no current to the supply wire. I checked the fuse box all ok and relay. But apparently there is another fuse somewhere under the dash, but I cannot find it and I cannot find anything about the fan on ElsaWin either! Any ideas?

13-06-13, 09:59 AM	#6
Malbec Grown up member Join Date: Jan 2013 Posts: 39	Help needed urgently please? Ok, I just cannot find why there is no power to my fan. I badly need to get the car working now, as I have a long journey planned for saturday. So was wondering is there any reason why I should not run a length of wire direct from the + post on the battery, through a fuse, then a thermo switch to the fan, to get it to work that way? If so, what sort of amp wire do I need and what fuse would I fit, is this safe I don't want to start a fire or ruin my electrics obviously. Hope someone can give me some help with this.

13-06-13, 07:50 PM	#9
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	If you consider that agressive, sorry, that's not my intention. In any case it's strange to read such a sure assumptions which goes against both schematics and ETKA [the official electronic spare parts catalog]. After all, you have 1991 A100 with 2.3 engine, which is rather simple. The only old audi using something like your imaginations is audi V8, which, as a luxury car, employs not one or two speed thermoswitch like the rest of audi range, but three speed fans, turned on by some bit of electronics embedded in instrument cluster, using info from coolant temp sender in flange and, yes, in radiator. In your case, if there really is no thermoswitch in your radiator, it's time to get one and find the connector left from previous one.