AC issue. I don't think it's the blend door.

[Rusty Shackleford]

So I'm out here in the shop all set to replace the blend door. Getting nice cold air from the passenger side with adequate volume. Passenger side isn't as cold, but not hot, and has less volume coming from the driver-center and driver round vent.



Got module and duct piece removed, removed the servo for the blend door, expecting to find pieces loose. Not the case on mine. I can manually cycle the blend door and it seems to be in tact. Reconnected the battery and cycled it from hot to cold and it seems to be functioning as it should. Hesitant to cut into something that seems to be working correctly.



Question is, obviously, what else could it be? I can view the gears that operate the diverter damper and it all functions as it should, seemingly, as well.



Any advice? Have the seat out, duct removed, module out of the way. Just perplexed on how to precede at this point.



Thanks

[Jeff_SS]

I'm in the same boat. I bought a replacement blend door and the morning I went to start taking things apart I decided to remove the blend door motor and look inside and sure enough the whole door was fine and the motor was turning just fine etc.
I went and got an ac recharge kit from auto zone with the blue and red dials and all the stuff and hooked it up and that's how I learned I have a leak somewhere in the system. So I've yet to track the leak down to know if its the compressor or condenser or what.

[Moto-Mojo]

Mine acted like yours...until it let go and broke the door completely. Then it was all mostly hot. As I have stated in other threads, I still get warmer (not hot) air on the pass side vs the driver's side after the 'fix.' It would seem to me either the new (aluminum) door is not completely sealing off the heater core or some other door/baffle is somehow letting warmer air bleed into the duct system.

My AC is tolerable now but I've yet to see a 90 degree plus day. It is a PIA to do the hack but odds are you'll be back down there again someday. Likely sooner than later. Tough call, man.

[Moto-Mojo]

If it's any consolation, you've gotten a couple of the bigger issues done already - the seat removed and the "snorkel" duct out. That sumbitch was a bugger to get back in. I ended up sanding the sharp flanged edges on the top of it and even put some lube on the thing. Then it slid right into position.

[Rusty Shackleford]

So after playing around with it all a bit more I've come up with a couple of possible scenarios



Either the door isn't completely broken yet, but starting to (as suggested above). Or the fan is actually blowing it open a bit, progressively more at increased fan speed settings. Maybe one causing the other?



One thing I found interesting, when cycled from extreme heat to extreme cool the motor travel right at 1/4 turn. When manually cycling the door itself from one extreme to the other, I get about 1/8 of a turn. The door moves freely and I feel a solid stop at each extreme. I even used a large stubby flat screwdriver in the coupling on the door to cycle it manually at varying fan speeds. The higher the fan speed, the more difficult it was to hold it in the cool position, it wanted to blow open. I didn't want to damage the motor trying to see how stout it is, but it'd have to be pretty stout, and given that I can see why these things break so often.





Working on it is definitely no picnic. Removing the seat isn't really too bad. Positioning a usable amount of light in the footwell, with my head, and keeping tools within reach is a comedy. Ought to be a riot with a hot-knife thrown into the mix.



I think I'm going to go ahead and cut into it tomorrow and see what's going on inside. I don't think I can hurt it any. Gotta figure this out pretty soon, Texas summer is going to be brutal otherwise.

[Rusty Shackleford]

Originally Posted by Moto-Mojo

If it's any consolation, you've gotten a couple of the bigger issues done already - the seat removed and the "snorkel" duct out. That sumbitch was a bugger to get back in. I ended up sanding the sharp flanged edges on the top of it and even put some lube on the thing. Then it slid right into position.

Yes, reassembly is a biotch!


I ended up removing the plastic bracket for the module, and the module itself of course. Putting the duct in first, it was relatively easy at that point. Then got the module bracket snapped back in place, the module slid into place, then plugged all the wiring back into the module. Dealing with the module that way wasn't easy, I just didn't see how I was going to get the duct in there any other way. I admit, the duct came out in a slightly violent way.



Should be easier to do again since I've done it once already,

[Moto-Mojo]

Interesting about the door 'blowing' open. I'll have to see if that happens with the much heavier aluminum door. I must have something else going on too. The compressor definitely cycles on/off too often, in my opinion. I was hoping the recharge would fix that and it did make it colder but if it would stay on longer it would simply be colder.

Any ideas why that is? Some high pressure side issue?

[Parts Peddler]

Originally Posted by Jeff_SS

I'm in the same boat. I bought a replacement blend door and the morning I went to start taking things apart I decided to remove the blend door motor and look inside and sure enough the whole door was fine and the motor was turning just fine etc.
I went and got an ac recharge kit from auto zone with the blue and red dials and all the stuff and hooked it up and that's how I learned I have a leak somewhere in the system. So I've yet to track the leak down to know if its the compressor or condenser or what.

The service valves are notorious leak points. I would suggest you start with those.

[Mr_Draco]

Have you checked your freon? The high side port has been recognized by GM as being prone to leak and they recommend it gets changed every year. Check the freon and if low, fill it up with some that has the UV dye so you can track down the leak.

[Rusty Shackleford]

Cut into it today, and while the door was definitely on it's way to breaking, cracked at the drive point and the whole door was slightly deformed in that same area. I don't think it's the whole issue though. There's a new door in it now, so we'll see on that. I'm going to check the refrigerant tomorrow when I get home, it might be a little low. The suction line isn't quite as cold as it should be. I'll run my leak detector over everything as well and see if it picks up anything.

[Rusty Shackleford]

Originally Posted by Moto-Mojo

Interesting about the door 'blowing' open. I'll have to see if that happens with the much heavier aluminum door. I must have something else going on too. The compressor definitely cycles on/off too often, in my opinion. I was hoping the recharge would fix that and it did make it colder but if it would stay on longer it would simply be colder.

Any ideas why that is? Some high pressure side issue?

I have seen the pressure switches get tired and cycle out on head pressure prematurely. You can try jumping it temporarily to see if that helps. If it does, replace the pressure switch pretty soon. Don't run it jumped for too long.

[Jeff_SS]

Originally Posted by Parts Peddler

The service valves are notorious leak points. I would suggest you start with those.

I just bought a new service valve and the socket to remove it. Guess I'll try that this weekend. Willing to try everything at this point after everything I've been through with this...

[Rusty Shackleford]

Definitely a leak at the high side port. Will get it fixed tomorrow.

[Moto-Mojo]

Welp, it's been over 100 here once or twice in N. CA and I will report that the hotter it got, the better my AC seemed to work. Once again, it was not Antarctica cold but enough to be comfortable in the cabin. It was all (nearly) worth it!