Engine Cooling Blower

[silverstream]

Can any body tell me where the heat sensor is positioned on the engine?
The Blower fan is operating all the time on my car.

 

[Dave Wilkinson]

There are several possible causes for the rear blower to run permanently. It's essential to identify if it runs ONLY with the ignition on or all the time (even with ignition off).

If it's the former, the chances are the relay has welded. You can swap with the oil cooler blower relay in the main fuse/relay box up front. R4 is the oil cooler one, R14 is for the a/c if you have it. Both relays are the same.

If it's the latter it's likely the NTC temperature sensor on the top of the blower plenum. It's stuck right on top of the outlet tube from the blower. It's used to sense engine air temperature and is intended to run the blower (with ignition off) if the engine is over-hot.

Regards

Dave

 

[Steve Brookes]

Dave, please correct my confusion about the blower and relay.

Assuming the engine is cool, are you saying that when you turn the ignition on (all lights on dash) that the blower should not run? If it does there is a problem with the relay. I thought that the only time it would not run in this situation is when you have the fan turned to the blue dot.

I'm of course interested in this because I've still not solved my HVAC current drain problem even though I've got a replacement final stage regulator. Damn intermittment electrical problems []

O/T I still managed to work round the problem by pulling fuse 1 while at Oulton and doing without ventiliation. It sure focuses the mind when trying to operate the window switches to demist the screen while doing 100 mph []

 

[silverstream]

Thanks for you prompt reply, sorry to be an idiot but where do I locate the blower relay?

It does only run when the ignition is switched on.

 

[l.chadburn]

hi
got problems with my heater as well. Mine blows all the time even with the ignition off. i ordered an NTC sensor from design 911, but they sent me the resistor that fits lower down. Going to keep it (only 20quid) and replace that as well.
Hopefully that will stop it blowing. also got front ones blowing all the time. I bought the front transistor regulator off of ebay, so waiting for that to come so i can fit that.
I also think that my servos are stuck in the position to allow full heat through.
Hopefully a little work should get those working again.

Just wondered that as the CCU also controls the oil cooler, if I remove fuse 1 permanently will it affect this?

lee

 

[Dave Wilkinson]

Sorry Steve, perhaps my reply was a bit too "economic"!! You're right though - the rear blower should not run if the temp selector is on the blue dot, otherwise it will run on slow speed. This is the problem of trying to diagnose problems with only half the story!! Because the system is so complicated the testing needs to be done under very strict conditions in order to know what happens, when.

John, the relay for the rear blower is located in the electrical panel in the engine compartment, on the left hand side with a cover held by 3 thumb screws. The fuse for the blower is in there too.

Lee, I think the answer to your question is ... No. Fuse 17 is for the CCU and the oil cooler blower fuse is number 2.

Regards

Dave

 

[Dekker]

There's a good read with pictures on the following link
http://p-car.com/diy/fan/

Dekker

 

[Steve Brookes]

ORIGINAL: l.chadburn

hi
got problems with my heater as well. Mine blows all the time even with the ignition off. i ordered an NTC sensor from design 911, but they sent me the resistor that fits lower down. Going to keep it (only 20quid) and replace that as well.
Hopefully that will stop it blowing. also got front ones blowing all the time. I bought the front transistor regulator off of ebay, so waiting for that to come so i can fit that.
I also think that my servos are stuck in the position to allow full heat through.
Hopefully a little work should get those working again.

Just wondered that as the CCU also controls the oil cooler, if I remove fuse 1 permanently will it affect this?

lee

Lee, your non moving servos are most likely related to your problems with the final stage regulator. I spent all day on Monday diagnoising my own HVAC problem and found that when I unplugged the regulator that I lost control of the servos.

I can also confirm what Dave said about fuse 1. On tuesday I had it pulled out while tracking at Oulton Park, if it had any effect on the oil cooler I would have been in big trouble under track conditions when the engine is working very hard. As it happened the oil temp never went above half way at any point in the day.