Monday, February 18, 2013

A/C - Driver side cold, Passenger side hot?

Air conditioning blows hot on passenger side but cold on driver's side

2009 Grand Cherokee A/c  driver side gets cold but the passenger side gets warm.

Take apart dash and look for blend door at A/C.

See if everything functioning correctly or not. If everything looks to be turning correctly then you can hopefully rule out the control head and actuators.

Set the temp and see if you can control temperature on heat. If you aren't able to control temperature on the right side when it's on heat then you know you have a right blend door problem, in that case the heater box will have to come out and be disassembled.

But if you can control temperature on heat but the a/c is warm on the right side it's likely a charge issue. The refrigerant charge you can understand.

If you read working of heater Box,it will help you to know the problem much better:

With the way airflow is set up in modern Chrysler heater boxes one side of the vehicle gets air from one side of the evaporator and the other side of the vehicle from the opposite side. 
When a/c charge becomes low it will be able to cool one side of the evaporator but not the other so it creates a temperature difference between left and right.
 If you are able to control heat ok then the first thing that will need to be done is evacuate and properly recharge that a/c and it should take care of the problem.But if heat is not getting controlled then definitely heater box has to be inspected.

Many a times the problem occurs even after the A/C system is recharged.
On that cases its the problem related to internal refrigerant leak in the evaporator or a broken blend door. 

Why i am mentioning about evaporator leak,because at our auto garage we have seen this.The evaporator is made up of a series of plates that are soldered together to make single cores, the evaporator is made up of a stack of these cores. Once in a while they will develop an internal leak and one side of the evaporator will cool and the other won't. This is uncommon but possible.

The other possible cause would be a broken blend door. If you're sure the charge is ok at this point the heater box will need to be removed and disassembled to inspect the blend door.


Here's the procedure,

First you will have to remove the entire instrument panel as an assembly. Please note that the bracing and everything comes with it, just removing the trim panels won't be enough. The steering column has to be removed or dropped, the center console removed, and then the entire instrument panel assembly. Once it is done then only the the heater box on the firewall  can be removed.

Brace is not very difficult to remove but it looks so,.The brace will not come out as it has two bolts and a screw holding it there and then it has a huge rivet looking pin,that has to be pushed out.

See the image shown below:----

The bolts above and below that are the ones that hold it to the pillar, they're either 13 or 15mm. Those are what needs to be removed.Once the bolts are out,the brace is loose to be easily removed.

You will also require basic tools and much is confidence to do this task.

Hope all goes well.



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