Front A/C is not cooling, rear is cooling great

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05_Tahoe_JW

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Hello, I'm new to posting on fourms. I have a 05 Tahoe with automatic A/C. It's a 2 wheel drive 5.3L and the rear A/C cools great the front is not at all.

I have replaced the EVAP coil in the dash (due to it was leaking)
Orifice tube, low pressure switch, accumulator and I also tried a A/C Controller out of my other 05 Tahoe to eliminate that as a problem.

I've went through all 4 blend door actuators and confirmed they are working correctly (I also tried DEFROST and it dose not blow cool air either)

The refrigerant line coming from the compresor that has a y and splits to the back ( is ice cold) and to the front accumulator ( is the same temperature as the engine compartment). Also the accumulator is warm as well. The low side line to the inlet side of the EVAP coil is Ice cold. I have removed this line with the y and inspected for any sign of blockage, but it is clean as a whistle.

I have vacuumed the system for 2 hours and let it stand for 2 hours. There is no longer a leak.
I charged the system with 2.5 LBS of R-134A

What do you guys think?
 

Bill 1960

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Going by your excellent description the orifice is blocked and not feeding refrigerant to the front evaporator.

Depending on where you are sourcing parts, it’s very easy to receive defective brand new parts from chyna. Also a very small bit of contamination can block the orifice.
 

OR VietVet

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Welcome to the forum from Oregon.

Again, this is the reason that I ALWAYS say, "When you have the system open, flush the entire system out and use quality Genuine GM parts. This may not be your problem but I don't like to open systems again. I did a lot of a/c work in KC, Mo. when I ran shops there, and I would not do the a/c job unless the flush was approved.
 

swathdiver

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Hello, I'm new to posting on fourms. I have a 05 Tahoe with automatic A/C. It's a 2 wheel drive 5.3L and the rear A/C cools great the front is not at all.

I have replaced the EVAP coil in the dash (due to it was leaking)
Orifice tube, low pressure switch, accumulator and I also tried a A/C Controller out of my other 05 Tahoe to eliminate that as a problem.

I've went through all 4 blend door actuators and confirmed they are working correctly (I also tried DEFROST and it dose not blow cool air either)

The refrigerant line coming from the compresor that has a y and splits to the back ( is ice cold) and to the front accumulator ( is the same temperature as the engine compartment). Also the accumulator is warm as well. The low side line to the inlet side of the EVAP coil is Ice cold. I have removed this line with the y and inspected for any sign of blockage, but it is clean as a whistle.

I have vacuumed the system for 2 hours and let it stand for 2 hours. There is no longer a leak.
I charged the system with 2.5 LBS of R-134A

What do you guys think?
Had this same issue with a Pontiac Montana, it was a relay burned out that prevented the second cooling fan from running.
 
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05_Tahoe_JW

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Thank you. I will replace it this weekend along with flushing the system . A mechanic told me that the rear A/C doesn't use the same condenser as the front A/c. Is this true or no?
Going by your excellent description the orifice is blocked and not feeding refrigerant to the front evaporator.

Depending on where you are sourcing parts, it’s very easy to receive defective brand new parts from chyna. Also a very small bit of contamination can block the orifice.
 

Bill 1960

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There is only one condenser ( in front of the radiator). There are two evaporators, in the dash and in the right rear corner of the rear cargo area (only when the optional rear a/c is installed).
 
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05_Tahoe_JW

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That's what I thought. Do you think it cold be a condenser issue being th rear A/c works great? And thank you for your time
 

Bill 1960

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If the condenser was a problem, the rear would not be cold.

What the mechanic may have been trying to convey is that on the GM parts lookup, there are two different condenser part numbers. One for front air only and a different-presumably larger- one for vehicles with optional rear air. But they won’t both be on a single vehicle. Its one or the other.

If you don’t know the history of this vehicle it’s remotely possible someone in the past installed the wrong condenser, but not likely.
And even if that happened, it would just have reduced capacity. It’s not going to make all the refrigerant go to one evaporator and none to the other.
 

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