The A/C on the subject vehicle is behaving abnormally while accelerating (not WOT) and with the climate control in Max A/C setting. Under these conditions, air flow is diverted from the panel vents to the defrost vents until I back off the throttle somewhat. When the air is on, it is cold, and in Normal A/C mode, it does not divert to the defrost vents under acceleration.
I have read numerous other posts regarding A/C, cooling fans, etc. I also found one regarding a red plastic vacuum tube near the firewall on the driver's side that might be related to this behavior. I found what I believe to be the correct vacuum line and see it going into a vacuum tree behind the intake manifold, but cannot see where it goes to. Any ideas?
Also, although my cooling system is full and my radiator less than 2 yrs old, I quite often see the temp gauge surge up near or past the "L" in normal, most notably when sitting idling at a drive thru window or excessively long traffic light and will frequently jump/surge. I jumpered the wire going to the coolant sending unit directly to ground and the gauge goes all the way to hot and remains steady once the ignition switch is turned on. I'm not certain if either of the fans are running when they should, however, when performing a KOEO test, I confirmed that the "puller" fan runs in both speeds and the "pusher" fan comes on as well.
What sensors are used to determine when these fans come on? The wiring schematic I have shows the cooling fans connected to the Constant Control Relay Module which in turn has connections back to the Powertrain Control Module which also has connections to the A/C controls system. Should I check/replace the coolant temp sensor (goes to computer), coolant temp sending unit (goes to gauge, not sure if goes through another control module first), or some other sensor(s) and or relay(s)?
Based on the gauge behavior, I am tempted to change the coolant temp sending unit, wondering about the coolant temp sensor as well.
Any and all ideas are greatly appreciated!
I have read numerous other posts regarding A/C, cooling fans, etc. I also found one regarding a red plastic vacuum tube near the firewall on the driver's side that might be related to this behavior. I found what I believe to be the correct vacuum line and see it going into a vacuum tree behind the intake manifold, but cannot see where it goes to. Any ideas?
Also, although my cooling system is full and my radiator less than 2 yrs old, I quite often see the temp gauge surge up near or past the "L" in normal, most notably when sitting idling at a drive thru window or excessively long traffic light and will frequently jump/surge. I jumpered the wire going to the coolant sending unit directly to ground and the gauge goes all the way to hot and remains steady once the ignition switch is turned on. I'm not certain if either of the fans are running when they should, however, when performing a KOEO test, I confirmed that the "puller" fan runs in both speeds and the "pusher" fan comes on as well.
What sensors are used to determine when these fans come on? The wiring schematic I have shows the cooling fans connected to the Constant Control Relay Module which in turn has connections back to the Powertrain Control Module which also has connections to the A/C controls system. Should I check/replace the coolant temp sensor (goes to computer), coolant temp sending unit (goes to gauge, not sure if goes through another control module first), or some other sensor(s) and or relay(s)?
Based on the gauge behavior, I am tempted to change the coolant temp sending unit, wondering about the coolant temp sensor as well.
Any and all ideas are greatly appreciated!