EYKAMP

I can't get my rear blower motor to turn on when the engine is shutdown and at a high enough temp that the blower should turn on.

I have replaced the NTC sensor, the relay has been switched w/ another, the ballast resister appears good. The A/C and Heater both work on low and high. But the additional cooling mode just stopped working. I am measuring 5 VDC at the NTC sensor probe....should it be 12 VDC? Is this the Control Unit going bad?

Is this going to cause any damage to be concerned about?

jimq

mine has never come on after shutdown as far as i know and it can get pretty hot here.

EYKAMP

Well. Mine used to and it runs for about 20 minutes.
If the heads don't fly off I guess I'm not going to stay up nights.

Thanks for the reply.
Dale

greenjt

I have also never had mine come on after shutdown.

Marc Shaw

Mine has never run after the engine is turned off either.

Marc
p.s. If the heads fly off - try to capture it on video (I'd like to see that).

Chris M.

Me neither.

c

CHASE

Mine has come on (quite surprising too) but only runs for a few minutes and sometimes in short intervals. Appears to cool the engine a little and then shut off, once engine warms again because blower has shut off it may come back on again. I thought this was normal. Maybe mine is not correct ?

Hambisa

My blower behaves the same as Brian's. As I live at the top of a hill, with about a half mile climb in second gear, the engine is always hot when I stop in the driveway, so the rear blower runs for a while to cool it off. It will also restart if the air temperature in the ducts starts to rise again. I believe this is normal and desirable operation. It is also a reason why I removed the rear undertray, to facilitate stationary cooling of the engine compartment.
Cheers,

JasonAndreas

The rear temperature sensor is an NTC (negative temperature coefficient) sensor so as the temperature increases the resistance decreases. With your multimeter you need to measure resistance (ohms) and not voltage. For the rear sensor you'll have:

0'C (32'F) = 28.8 - 36.4 kOhms
25'C(77'F) = 9.0 - 11.0 kOhms
50'C(122'F) = 3.1 - 4.0 kOhms.

The run-on feature of the rear blower activates if the temperature is greater than 95'C so your resistance measurement would have to be around 1 - 1.4 kOhms. To test the whole system you could try placing a 1kOhm resistor inplace of the temperature sensor (I've never tried but in theory it should work) and then turn the ignition off (the car has to be running for a minimum of 30 seconds beforehand) and the rear-blower fan should stay on.

CHASE

My rear blower fan also will come on for a few seconds when I first cycle the ignition key with a cold motor. Is this also normal operation ?

dsmyth

Mine stays on for about 10-15 minuites after I shut down.

jimq

yes
seems like it depends on the car as to how the fan decides to work

CHASE

Cool, Thanks Jim !

DarrylH

Couldn't one simply shut off the engine, twist and pull the temp sensor from the tube, and warm it with a heat gun or hair dryer? It would be more of a go / no-go test, but if the temp sensor is working, the fan should start once the temp sensor gets up to 95C. (Remember, that's really hot, boiling water hot...so be careful!) Or am I missing something?

warmfuzzies

Darryl,

when I had my blower problems, that's exactly what I did to make sure it wasn't the blower or fuses.

kevin