Climate control problems? Read This!

[kellen302]

How does the ATC sensor unplug from the vacuum harness? I have a donor sensor from the junk yard that I just cut the hoses on, but how does it actually disconnect? There is a white collar around the hoses that I have tried pushing or pulling and that doesn't seem to release anything.

[gadget73]

i want to say there is a small plastic tab that you have to push to get it to unplug.

[sly]

That clip is very stubborn.

[gadget73]

and the rubber connector thing likes to become one with the sensor. Might have to stick a pick in there to help get it apart.

[over2tonsofFun]

My 90 MGM with ATC will blow hot only when it is running above 40+ mph. So, should be a vacuum leak? I will have to look into it when I get a chance. May unplug the line to the actuator for the wife to get heat.

Tim

[gadget73]

90 may or may not be vacuum actuator. They changed to electronic controls in the late boxes, pretty sure 91 was electronic, I think '90 may be as well. If it is, none of the vac stuff applies.

Honestly that sounds more like low coolant or some sort of restriction in the core. A vacuum leak won't cause it to do that.

[over2tonsofFun]

It is now barely putting out any heat. Even at highway speeds. Coolant level is up. Any other ideas?

Thanks
Tim

[gadget73]

blend door not moving fully to hot or clogged heater core. Assuming the engine comes up to a decent temp.

Clogged core is easy to check. If one hose is hot and the other is cold, its not moving any water. Both should be pretty hot. If neither are hot the engine isn't coming to temp or the core is so clogged water won't even move through it.

[sly]

Could also be dirt/dust/mud/grime clogging the fins of the heater core and not allowing flow through it.

[clutch47]

Excellent info. Thank you.

[gadget73]

if the fins are packed with dirt it won't move much air through the vents.

[over2tonsofFun]

It wound up being the whole control unit. replaced it works great now.

Tim