97 Suburban Rear a/c doesnt work

[00SS]

Like it says in the title. Its blows air but it isnt cooling. It also shows a draw on the ammeter when you turn on rear air. The rear heat works. Thanks for the help.

[bobcat5544]

So you have ac in the front only and the rear blow warm at all time

Do you hear any clicking in the rear of the vehicle when moving the rear controller temp selector?

[00SS]

So you have ac in the front only and the rear blow warm at all time 

Do you hear any clicking in the rear of the vehicle when moving the rear controller temp selector?

 

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Nah. No clicking. Using the rear temp controller you can select heat and the heat works. Is there somewhere that I can find a schematic. I havent been able to find a book locally. If I saw a schematic I am sure I could solve this issue. I had someone tell me that it was the rear evaporator. But does that explain the draw on the ammeter?

[bobcat5544]

Rear Hvac

[00SS]

Rear Hvac

 

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Thanks a ton

[Z-Factor]

I would say there is a good chance your expansion valve is clogged up. It commonly happens, and is almost impossible to clear. If that is your problem, you will need to have it changed, but make sure to try and flush the system first.

 

Let us know what you discover.

 

[00SS]

Thanks alot. I will check into the expansion valve. Where is the expansion valve located. I replaced the compressor, reciever dryer, and orifice tube less than a year ago. Everything works great except the rear.

[bobcat5544]

Did you replace the compressor for internal failure (make noise, knock grind). if you did and the ac system did not get flushed out then the rear office may be clogged.

[00SS]

Yes. Replace compressor because of failure. I did not "flush" the system. Just pulled a vaccuum.

[bobcat5544]

Ok before tearing into the ac system do this, run the ac with all settings on cold and max. Let it run for about 5 min. Under your vehicle on the passenger side there along the frame there should be two line that run along to the rear, if you touch the lines one should be ice cold the other should be warm / cold, if both lines are warm or hot then you have a restriction ant the orifice, if not then the evaporator blend door is not working or and control unit is bad.

 

Let me know what you find and then I will get you instructions on how to fix the problem

[00SS]

ok...I have done this before but I will do it again. I ran it before and the lines were warm. I will do it again.

 

Thanks

[bobcat5544]

Ok if the two lines that go to the rear evaporator are warm then there is a restriction at the Thermal Expansion Valve at the rear evap.

 

Recover the refrigerant.

Remove the rear quarter interior trim, as necessary.

Remove the right rear quarter trim panel.

Remove the right rear wheelhouse.

Disconnect the rear heater hoses from the auxiliary heater core (7), if equipped.

Disconnect the auxiliary refrigerant hoses from the auxiliary evaporator (6). Disconnect the electrical connectors, as necessary.

 

Complete the following steps in order to remove the heater/evaporator case cover:

Remove the case clips.

Remove the 11 screws.

Separate the case halves.

Remove the pipe insulator.

Remove the evaporator core.

 

Complete the following steps in order to remove the Thermal Expansion Valve from the evaporator core:

- Remove the clip retaining the capillary tube to the suction pipe.

 

- Remove the TXV from the evaporator inlet pipe.

 

Installation Procedure

 

Install the TXV to the evaporator core by completing the following steps:

- Install the TXV to the evaporator core inlet pipe.

 

- Install the capillary tube to the suction line.

 

- Install the capillary tube to the retaining clip.

 

Install the evaporator core.

Install the pipe insulator.

Install the heater/evaporator case cover clips.

Install the blower motor (2) to the case.

Install the auxiliary case to the vehicle.

Connect the auxiliary refrigerant hoses to the auxiliary evaporator (6).

Connect the rear heater hoses to the auxiliary heater core (7), if equipped.

Connect the electrical connectors, as necessary.

Install the right rear wheelhouse.

Install the right rear quarter trim panel.

Install the rear quarter interior trim.