Quote:
Originally Posted by dhjenkins
I did do a little CCU diagnosis by using a temperature probe & my fluke MM, though I didn't test any resistance. After driving for about 20 minutes, I took the ambient temperature reading from the meter and set the rotary dial to that. When I did that, the heat shut off completely and the blower slowed down. When I decreased my set temperature, the blower sped up (however A/C is non-functional right now due to leak) and I got cool air (it was around 69 that day). When I returned the dial to the ambient temp, the blower slowed down again. When I increased my set temp., I got more blower and good heat.
I don't believe it's a stuck thermostat, because the last time I drove to work, it was pretty close 80-85 when I parked it. I then got the RPM's up to around 4k, and the temp dropped quickly down to 60, indicating that the thermostat must have opened.
Honestly, if I don't hit any lights, it's less than a 6 minute drive @ 35mph...
My '00 GMC Sierra barely has heat by the time I get to work, too. Of course, that's why I have remote start  |
Sounds like you did a pretty decent test of the CCU, the blower speeds and temp change behavior is correct as you noted.
So - You are getting good heat, just not in that short a drive, correct? If you drive further, you get good heat?
Perhaps the aux coolant pump is dead, if your car has one.