I have a 2007 is250 and the blower motor keeps turning off and on, it will run for a little while and then completely stop then turn on for a few seconds and turn back off. Does it constantly. I’ve replaced the blower motor twice. When the blower motor is working I can adjust the speed no problem. Any idea what the problem could be ? It’s driving me crazy.


thank you.

 

There's a thermistor on the lower right side of the steeing wheel. You'll see what looks like litttle rectangle with vents. Check if its clogged with lint from years of use. The dash panel will have to be removed. To access the sensor. Maybe if its dirty clean it with CRC MAF cleaner.

You can search on how to replace the push start button. This will give you some directions on how to remove said panels where it's located.


If that doesn't work it could be an issue in the wiring, or the AC amplifier.

 

ill definitely took a look, it’s really driving me crazy. I thought it could be the blow motor resistor at first but im able to adjust the speed from the lowest to highest setting so I would assume if it was the resistor then I would not be able to change the speed. I was also thinking maybe the blower control module. It just blows my mind that it will turn on and run perfect and then keep turning off and back on. If the car sits for 24 hours also the Blower motor always turns on immediately but after a few minutes it turns off again. I’m tired of messing with it but I have to get it fixed lol. Thank you.

 

Is there a chance it could be the AC amplifier also ? And also I can’t find a blower motor resistor anywhere, does the AC amplifier serve as the resistor ?

 

Yeah I think it what took over now. My old GS400 had the old style resistor pack behind the blower compartment.

Also have you checked the freon?

 

That would explain why I can’t find the resistor lol, it just dawned on me today that the AC amplifier might serve as the resistor. Would the AC amplifier cause those symptoms of turning off and on constantly ? When it turns on it will blow air for maybe like 10 minutes and then stops and on for 2 seconds and then back off and finally the blower motor will just stop working until the morning or sometime the next day. Or would you still lean more towards the thermistor ?

 

It's hard to tell what it will do. First sign of the old syle it would just work on one speed "High". With that said you would have to bypass it and ground the blower to the chassis.

I think also if it was the amplifier it would at least light up the check AC light. There is a diagnostic procedure on the unit. I just forget the buttons to use on the Non Nav.