AC Questions

[scape]

85 c10 original system converted to 134a. Just had it vacuumed down and charged. New compressor, evaporator etc. blows cold but only out of heater vent. Where to start on the vacuum lines for that? Also, I have noticed even with the controls set to off the compressor will cycle. Is that normal or being caused by my other issue?

 

[gmbellew]

remove the vertical piece on the ductwork that you can see under the dash. then you can watch the door operations and look for issues before diving deeper.

 

[bucket]

Airflow out the heater vent only is normally a lack of vacuum. If you don't hear hissing (while running) from the hvac controller, first thing to check is always the vacuum supply line coming off of the intake manifold and the vacuum reservoir under the hood.

 

[Finkaire]

And no, compressor shouldn’t be engaged unless in defrost or A/C mode

 

[scape]

Got the vacuum issue resolved. Have air at vents now although switching to defrost still doesn’t seem to force all the air to those vents. Still having the compressor kick on after all controls are turned to off.

 

[AuroraGirl]

Got the vacuum issue resolved. Have air at vents now although switching to defrost still doesn’t seem to force all the air to those vents. Still having the compressor kick on after all controls are turned to off.

something is electrically engaging your compressor unless its stuck. unplug it. still run?
Then your doors, could be old tired vacuum motor or maybe something is stuck, or weak vacuum, or not enough sealing for the reservoir and the lines to maintain the door position. If you drive WOT does the vent selection start to shift back to defrost vents?