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Auto Air Conditioning & Heater Repair/A/C not cooling in the back cab area

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Expert: - 2/13/2011


Question
I have a 1997 chevy suburban. Ac unit in the front works ok. A/C blows cold air. The back part of the suburban does not cool the back fan motor works fine it blows hard but blows hot air while the front blows cold air. Why would that be?

Answer
Hello Dwayne
We are a UK company and not familiar with your vehicle. The following is a guide only and may help you

Does the rear system have a separate evaporator and expansion valve ?
If so with the system running get underneath the vehicle and locate where these are, they will be from the center of the vehicle rearwards under the passenger or driver sill or right at the back underneath the luggage compartment
Locate the point where they enter the vehicle and get your hand on the pipes, one should be cold and one should be warmer (the thin one)
If they are the same temperature the expansion valve is not working properly, before you go stripping it make sure the vehicle has the right amount of gas. Only an approved a/c center will be able to tell you this. Low gas is the most common reason for poor rear a/c.

If there is a separate rear control for the heater and a/c there will also be a control to shut off the hot water supply to the rear heater. This is a common failing on the Chevrolet Day Van for example.If the separate rear control is electronic there could be a problem with a temperature sensor if you have one.

If there is no separate control and expansion valve for the rear the cold air from the front is only ducted to the rear coming out on the rear passenger feet, usually in the tunnel behind your gear shift.
Make sure the flap is opening to allow this to happen.
See how you get on with this and let me know if you need more help

Auto Air Conditioning & Heater Repair

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Paul Evans/ www.chillywillys.org

Expertise

Any question related to the function or malfunction of vehicle air conditioning excluding model specific problems with the heater controls. We are a UK based company and are unlikely to be familiar with the exact make and model of American vehicles. We will always at least try to guide the owner towards what the problem is likely to be in this instance We may struggle with none specific electrical issues related to the a/c without seeing it but it is likely we could narrow the problem down

Experience

Director www.chillywillys.org specialising predominantly in UK vehicles, fleet, rare and collectables. Although all a/c works on the same principal US vehicles have different controls and electrics. 12 years experience automotive and aircraft air conditioning. This is our sole source of revenue, we see lots of a/c issues that we are able to diagnose accurately mainly down to experience. UK have garages caught on to a potential revenue stream within the last few years but sometimes struggle with the problems as they don't see the issues that often........to be fair they could get their own back and ask me to change a timing belt ! Certain vehicles have known issues, we can help with that and also anything that is obvious to us but not necessarily to the bamboozled owner....... a/c is relatively new here and owners are catching on to maintenance but are sometimes still misguided by inexperienced individuals a bit timid to say' I don't really know

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