Hi, I am going to take the car out this afternoon. My rear blower fan cycles on and off regardless of CCU control position?????? Somebody mentioned this part

http://www.pelicanparts.com/cgi-bin/...o%2C%20Each%20

but is there a way to jump/test system before I buy a part i do not need?
THANKS!!
Steve

 

Steve,

The part you linked to is a temperature sensor which determines the temperature of the air exiting the engine chamber towards the heat exchangers. The purpose is for the CCU to determine the running temperature of the engine (or, rather, the air surrounding it) in order to allow the CCU to run the electric blower to assist in engine cooling after the engine has stopped.

To determine if the part is faulty, just disconnect it. It cannot then produce any signal to the CCU to mess with the rear blower.

Another possibility is the ballast resistor. This is clipped into the left side of the blower plenum and reduces the current to the blower to provide the slow speed operation. If the resistor is short circuit the blower will run at full speed and it's likely the CCU will shut it off quite quickly. It's also possible you have a faulty relay although, from your description, I'd say that's less likely. You can swap the relay for the oil cooler blower from the front fuse/relay panel in the luggage compartment to check - they are the same part.

Hope that helps.

Regards

Dave

 

I just replaced the temperature sensor and blower relay in my car. The rear blower fan was running for about twenty minutes after I shut the car off. Now it doesn't, so it was 50 bucks well spent plus it was an easy fix.

 

Does your blower motor cycle regardless of engine temp or only after it is up to normal operating temp? Trying to diagnose what sounds to be the same issue.

 

Hi, My fan starts up the second I turn the key, even before engine start> It runs for 5 seconds, shuts of for one second and on and on???
I am going to swap relays as per Computamedic's advice? I am guessing that big fan is for cabin heat and not critical to cooling the engine? If this is true and my A/C works with rear blower disconnected, that is what I will do short term?

HELP!!!!!!!!

 

Hi, I swapped relays with no change? What is the purpose of the rear blower? Mine nevedr stays on after shut down? I am going to try out A/C and see how efficient it is?
HEEELP!

 

A/C is frosty!!! Should I just disconnect power plug to fan for the summer?

 

Did you try disconnecting the sensor on the top of the plenum?? At least that would prove if it's the source of the problem.

The rear blower provides the positive air pressure to open the diverter flaps to the cabin when heat is required. It also doubles as additional engine cooling if required after shut off.

The a/c makes no use of the rear blower.

Dave

 

Hi, yes I disconnected temp probe and nothing changed?

 

I think the next thing I would check would be the ballast resistor. If it IS short circuit, disconnecting it from the wiring should stop the blower running completely. If it still runs with the ballast out it would suggest a problem with the relay (already checked) or the CCU itself.

Dave

 

I unplugged that little coil/resistor thing, no change. must be CCU?

 

If the blower still runs with the ballast unplugged (i.e. wires disconnected) there must be power supplied via the high speed circuit. I'll have to do a bit of research to figure out the circuit but I think it's beginning to look like a CCU fault.

Dave

 

Have you checked the fuse for the blower? Maybe it's partially blown i.e. just about makes a circuit for a second or two every now and again. Just a thought.

 

Thanks, i read somewhere it should be upped to a 30 amp. When i started the gremlin hunt I checked fuse for correctness. When the fan cycles, the relay is doing it's job as I can fell it clunking. I just wonder where it gets the idea that it needs to be running? I am going to try the ballast plug even though I recall unplugging it before. If i jump the ballast can I do any damage and while I am jumping, what about jumping/bridging temp sensor?
THANKS!

 

The rear fan is controlled by the CCU. Do you have a set of wiring schematics?