AC air vent block issue!!!

[AzDiamondBlue]

The Tech-2 was the tool these vehicles were designed to be worked on with; along with the shop manual. They can be had now for about $300-350 and quickly pay for themselves. With this tool, you can know which actuators failed and why and perform the calibration the proper way afterwards. This knowledge alone will pay for the machine in money not given to a shop. If the AC is low on refrigerant, it will tell you the pressure and you can look that up with the ambient temperature to see if it is low.

The shop manual can be purchased from vendors on ebay in download pdf form or disc and or you can get a subscription to it at AllDataDIY. The two go hand in hand when troubleshooting.

@gpracer1 Marc, What do you think? You've forgotten more about AC systems than I know.

Hello. You seem to know bit about the Tech 2. Do you know off hand if it will go down to a 2004 Yukon, or is it just for newer ones? Thanks!

 

[AzDiamondBlue]

Hello. You seem to know bit about the Tech 2. Do you know off hand if it will go down to a 2004 Yukon, or is it just for newer ones? Thanks!

Found my answer! Thanks for the tip. Buying a Tech 2...might save me some headaches

 

[PlunkZ71]

Well... went on a 12 hour trip to Colorado from Texas. evacuated the system, new orifice tube under the hood, sucked it down and filled to spec. the trip there was fine but on the way back into the texas heat, the symptoms started towards the last leg of the drive. I pulled in the driveway and popped the hood and the accumulator/drier was frozen solid. Im sure the evaporator is freezing as well causing the air not to flow through the vents. So whats the next step to figuring this issue out? Refrigerant temp sensor? Low pressure switch?

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[kbuskill]

Well... went on a 12 hour trip to Colorado from Texas. evacuated the system, new orifice tube under the hood, sucked it down and filled to spec. the trip there was fine but on the way back into the texas heat, the symptoms started towards the last leg of the drive. I pulled in the driveway and popped the hood and the accumulator/drier was frozen solid. Im sure the evaporator is freezing as well causing the air not to flow through the vents. So whats the next step to figuring this issue out? Refrigerant temp sensor? Low pressure switch?

View media item 27965

Unfortunately GM cheaped out and didn't install a cabin air filter in the NNBS trucks.

I would start by buying the cabin air filter retrofit kit which comes with the door and filter and I would cut the "door" open and use a good foaming coil cleaner and clean your evaporator coils really well before installing the new filter and door.

Most of the time if an A/C is freezing up it is either a freon/pressure issue or a dirty evaporator coil not allowing enough air flow.

My 2 bits... YMMV

 

[PlunkZ71]

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Unfortunately GM cheaped out and didn't install a cabin air filter in the NNBS trucks.

I would start by buying the cabin air filter retrofit kit which comes with the door and filter and I would cut the "door" open and use a good foaming coil cleaner and clean your evaporator coils really well before installing the new filter and door.

Most of the time if an A/C is freezing up it is either a freon/pressure issue or a dirty evaporator coil not allowing enough air flow.

My 2 bits... YMMV

Thanks for the tip but I actually just retrofitted a cabin air filter right before I left and evacuated the system and charged to spec. Evap looks new when i took this pic through the hole i cut for the filter. I rinsed the condenser off as well. I have noticed that the compressor clutch never seems to disengage when the ac is on.

 

[kbuskill]

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Thanks for the tip but I actually just retrofitted a cabin air filter right before I left and evacuated the system and charged to spec. Evap looks new when i took this pic through the hole i cut for the filter. I rinsed the condenser off as well. I have noticed that the compressor clutch never seems to disengage when the ac is on.

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Good to know that's not the issue... its possible that it could a pressure switch or temperature sensor...as mentioned before, a Tech2 would be very helpful in determining the culprit.

 

[PlunkZ71]

Good to know that's not the issue... its possible that it could a pressure switch or temperature sensor...as mentioned before, a Tech2 would be very helpful in determining the culprit.

Thanks again. As much as I hate stealerships, I think i'm going to bite the the bullet and get the dealer to do a diagnostic check for $110. At least then ill have a leg to stand on and I can plan my attack.

 

[kbuskill]

Thanks again. As much as I hate stealerships, I think i'm going to bite the the bullet and get the dealer to do a diagnostic check for $110. At least then ill have a leg to stand on and I can plan my attack.

I hear you... just FYI... 3 stealership diagnostic fees would pay for a Tech2 clone and you could use it as much as you want/need.

Just something to think about.

 

[PlunkZ71]

I hear you... just FYI... 3 stealership diagnostic fees would pay for a Tech2 clone and you could use it as much as you want/need.

Just something to think about.

Can you recommend one to get or link me to a known good one? Ive been debating getting one. Ive heard that there is a seperate sd card for GM trucks in order to read ones like the Tahoe. Also, im sure the learning curve will slow the process down.

 

[kbuskill]

Can you recommend one to get or link me to a known good one? Ive been debating getting one. Ive heard that there is a seperate sd card for GM trucks in order to read ones like the Tahoe. Also, im sure the learning curve will slow the process down.

@swathdiver
@iamdub
@Rocket Man
@Doubeleive

One of these guys can surely point you in the right direction for the Tech2.