A/c not working after hear core replacement

[Yakman01]

Hey everyone! That's for all the help!
2001, 4.3L V6, LS, Auto

I can hear the compressor engage when I turn the A/C on so I know it's getting power.

Did a heater core replacement over the weekend and all it fine there. Once this was done I found that the A/C is not blowing cold. All switches work inside. I actually rechecked all connections under the dash yesterday and there are no problems/disconnected/pinched wires.

When I did the core replacement I did have open and remove the plastic cover over what I have now learned to the evaporator which is connected to the silver canister. Any wires that I disconnected I rechecked all wiring connections under the hood and all are good. I did unscrew the plastic covers on the pipe connected to the silver canister and found the valve near the front of the vehicle was leaking/bubbling after the cap jumpped into my hand.

I still need to get the dash back in, which I am doing this afternoon, so I'll check again after the dash is back in.

Any suggestions would help.

[MT-2500]

Automatic or regular AC/heater controls?
Did AC put out good cold air before replacing heater core?
Is all tempt and other AC/heater doors working good?
Good engine vacuum to controls?
If AC valve leaking you may have lost R-134.
What is low and high side pressure readings with compressor running.

[Yakman01]

I assume manual as I have to move all switches. A/C worked great before the replacement. I had the blazer for about two months before the core started leaking.
As for the temp and AC door working well - as far as I know. How do I check? I know when I was pulling the dash there was a black triangle looking thing on the passenger side attached to the heater core housing that believe attached to one of those doors. I am going to check on Sunday to see if the door/triangle thing is at the wrong orientation.
I assume the varous colored tubes under the dash are the vacuum tubes. I'm going to check them again.
Could it have taken the A/C that long to leak out?
The AC pressures will be checked once it's all back together

[MT-2500]

Switch temp cold to hot and to cold and see if black triangle actuator motor is moving and working.

[Yakman01]

Thanks. I'll let you know. Then I'll still have the pressures checked regardless

[Yakman01]

Actuator motor is working fine and all vacuum hoses appear to be fine. Now after starting the vehicle and letting it warm up the air running I touched the the two lines coming from the compressor. One was cool and the other was hot. Is this normal?

20 mintues later:

OK I've learned the silver canister is the accumulator which is in turn connected to the evaporator core. Assuming that the evaporator core pulls the moisture from the air and discharges the moisture on ground under the car, I idled for about 20 minutes to allow everything to warm good and try to cool everything down. When I shut off the engine I did find the discharge water coming from the evaporator dripping on the ground. Is it safe to say that AC is cooling but not inside the cabin? I'll still have the AC checked later once I exhaust my other options.

[MT-2500]

You need to get gauges put on it to check AC operation.

[Yakman01]

First let me start by saying thank you to everyone on this forum that have helped me on this issue and all the other information that has been posted!!

OK - I did get to a shop that checked pressures and all were normal. Lucky the mechanic that did the check and recharge (did that to make sure all is good) used to work for a Chevy dealer and knew ALOT about Chevy's. He was able to diagnose that there was something blocking the movement of one of the temperture control doors - UNDER THE DASH.

Well after I pulled the dash and air box - AGAIN - I found that when I had pulled the center air grate one of the clips had pulled off and wedged itself under one of the doors. Once that was fixed I checked it BEFORE putting it all together again. A/C was working!!!! A gift from GOD in Florida - still in the upper 80's in November!! With help from a friend we got everything back together in record time. Everything worked great - until we had a Florida cold snap (65 degrees) Yes - I turned the heat on. Guess what wasn't working? Yeah the heat

Well with flashlight in hand on Sunday I found the wire for the servo that controls another door was not connected. NO WAY I COULD GET IT BACK IN WITH OUT PULLING THE DASH - A THIRD TIME!

Finally all done - BOTH heat and A/C are working - just in time too the temps are in the mid 30's here.

Thanks again!!

[Jerry80871852]

Originally Posted by Yakman01

First let me start by saying thank you to everyone on this forum that have helped me on this issue and all the other information that has been posted!!

OK - I did get to a shop that checked pressures and all were normal. Lucky the mechanic that did the check and recharge (did that to make sure all is good) used to work for a Chevy dealer and knew ALOT about Chevy's. He was able to diagnose that there was something blocking the movement of one of the temperture control doors - UNDER THE DASH.

Well after I pulled the dash and air box - AGAIN - I found that when I had pulled the center air grate one of the clips had pulled off and wedged itself under one of the doors. Once that was fixed I checked it BEFORE putting it all together again. A/C was working!!!! A gift from GOD in Florida - still in the upper 80's in November!! With help from a friend we got everything back together in record time. Everything worked great - until we had a Florida cold snap (65 degrees) Yes - I turned the heat on. Guess what wasn't working? Yeah the heat

Well with flashlight in hand on Sunday I found the wire for the servo that controls another door was not connected. NO WAY I COULD GET IT BACK IN WITH OUT PULLING THE DASH - A THIRD TIME!

Finally all done - BOTH heat and A/C are working - just in time too the temps are in the mid 30's here.

Thanks again!!

Now you know all about removing and replacing the dash.

I've had to put 2 heater cores in my blazer, after the 1st one I said I would not do that again, but I did!

[MT-2500]

Originally Posted by Yakman01

First let me start by saying thank you to everyone on this forum that have helped me on this issue and all the other information that has been posted!!

OK - I did get to a shop that checked pressures and all were normal. Lucky the mechanic that did the check and recharge (did that to make sure all is good) used to work for a Chevy dealer and knew ALOT about Chevy's. He was able to diagnose that there was something blocking the movement of one of the temperture control doors - UNDER THE DASH.

Well after I pulled the dash and air box - AGAIN - I found that when I had pulled the center air grate one of the clips had pulled off and wedged itself under one of the doors. Once that was fixed I checked it BEFORE putting it all together again. A/C was working!!!! A gift from GOD in Florida - still in the upper 80's in November!! With help from a friend we got everything back together in record time. Everything worked great - until we had a Florida cold snap (65 degrees) Yes - I turned the heat on. Guess what wasn't working? Yeah the heat

Well with flashlight in hand on Sunday I found the wire for the servo that controls another door was not connected. NO WAY I COULD GET IT BACK IN WITH OUT PULLING THE DASH - A THIRD TIME!

Finally all done - BOTH heat and A/C are working - just in time too the temps are in the mid 30's here.

Thanks again!!

You are welcome.

And thanks for posting back how it went and the repair to get it going good.

Good Luck