Massive electrical gremlin under ma bonnet!!

[RPoul 10]

Battery was dead this morning ran back in and recharged it and reconnect it all fine and drove off. Stopped for gas on the trip and heard the radiator fan on stage 3 spin chose to ignore it as I was running late I checked the temperature on the way and it wasn't high so I knew something was up and it has never gone to stage 3 before.

 

Got back home and the fan didn't switch off as it used to when cooling down. I've looked up the various problems and solutions others have had and tried them to no avail (disconnecting the thermo sensors didnt help either). After unplugging the radiator fan I also found that the aux pump was also not switching off and fuse 15 (electronic ignition, idle stabilizer etc)had blown but the car still started and ran fine which I though a bit odd. I changed the fuse anyway but it blew straight away.

 

I was just wondering if anyone had any suggestions or similar problems which they've managed to sort out before I call out an auto sparky.

 

Any help would be greatly appreciated as I don't fancy cycling into work with the weather as it is!!

[RPoul 10]

Did all the coolant component tests and narrowed it down to the radiator thermo sensor which when unplugged stopped fuse 15 blowing and stopped the radiator fan from going off. Still not sure why fuse 15 is blowing though. A worn out thermo sensor wouldnt cause this would it? There was no obvious sign of deterioration when looking at the sensor and the plug.

[vw rule 19]

Hello there,

 

it depends really on how the sensor has burnt out if it has gone that is,

if the inside windings have melted and fused together,

that can cause an over load short circuit that will draw too many amps,

which in turn blows the fuse.

 

the multi plug for the radiator fan / fans,

you can some times use a split pin to join / bridge the connectors together,

to test the operation of the fan speed, just to see if the fan sensor switch is at fault.

 

You've normally got an earth a live and a secondary earth that switches to live via a control unit,

which gives you the various speeds or switches between one fan being on and then two being on at full speed.

 

On the 2.0 16v they have a 3 pin multi plug for the rad fan,

and on the VR6 I think they have two sensors for the two speeds,

plus there might be another for when the air con is used to cool the air con radiator.

 

 

Hope this helps.

 

Si

[RPoul 10]

Thanks Si

 

I did all the test on the fan from the definitive cooling guide and it worked fine. I have found that the fuse doesn't blow straight away, it might be blowing when the fan comes on? Not sure.

[RPoul 10]

Did a coolant flush found that the fuse inst blowing when the fan comes on. Seems to only do it when driving around maybe something to do with the ECU?

[RPoul 10]

or maybe a relay?

[fla 9]

looks like the fan is drawing too much current - so might need to replace the fan (bearing mights be worn. Try and apply 12V directly with an ammeter in series and see what the draw is. You'll know immediately from that.

[RPoul 10]

Yeah I thought it might be something to do with the cooling system but when I flushed the system out I had got the temperature up so that the fan would come on. When it kicked in the fuse didnt blow. From the looks of the fuse diagram fuse 15 manages the ECU, ignition and idle control problem is I dont know where I should be looking for problems.