A/c stops blowing after about 20 minutes

[Rman1958]

Replaced the compressor, a/c line with little valve screen thing and dryer, but after about twenty twenty five minutes it stops blowing so I turn it to vent and wait a few and when I switch it back to a/c it blows cold again, Took the blower motor out and vacuumed off the evaporator and it was not dirty. What gives on the a/c of this truck???

 

[kad]

Does it only do it on AC or does it do the same on heat? I had issues with the blower motor resistor on my '01 Dakota a number of years back where the resistor pack would overheat and shut off until it cooled down. It turned out to be a bad blower motor that was drawing too much current.

-K

 

[Rman1958]

No,the heater will blow all day

 

[ouch1011]

The cycling switch is likely not working, so the evaporator is turning into a block of ice. Turn on the AC, set the engine rpm at about 1500 rpm and watch under the hood to see if the ac clutch ever cycles off. If it doesn't, replace the cycling switch. I believe it is attached to the accumulator.

 

[Rman1958]

That is something I never heard! Thanks and that will be replaced.

 

[ouch1011]

You should be able to replace the switch without needing to discharge/recharge the ac. There is a Schrader valve on that fitting (like the valve in a tire stem) so it shouldn't leak

 

[17CrewCab1500]

Blower Resistor - had the issue on my 2007

 

[Cool_Hand_Luke]

I think I may have the same issue. AC stops blowing cold but if i shut it off it comes back on. I was thinking about pressure switch (tranducer) gone bad. I'll try to replace it and see how it goes. I also noticed, blower fan will not work on slowest speed. It might be related..dont know.
Did you solve your AC issue??