A/C blowing cold on driver side and warm on passenger side

[evnizio]

Had A/C recharged and no change .Bypassed heater core and still temp on driver side is 15 degrees colder than passenger side

Julian Stumped

 

[Topzide]

Are you experiencing a blend door issue? Confirm that all doors are moving as should. The recirculating door may not be closing all the way. Others have found the foam seals failing and blocking the doors from closing and sealing properly. Also check for vermin (mice) problem. Hope is something simple and you don't have to pull the dash for repairs! Did that on my 1500! What a PITA!!!!!!!!!!!!!!!!

 

[evnizio]

I had concluded that it had to be a blend door issue but now I am stumped since I bypassed the heater core with a hose so there is no hot water coming into the cabin now!!!
Foam seals are bad though
No critter problems!!
Check air speed coming out of the vents?

 

[petersonj]

I had concluded that it had to be a blend door issue but now I am stumped since I bypassed the heater core with a hose so there is no hot water coming into the cabin now!!!

Although a blend door not operating properly can affect air temperature coming from the vents, it cannot differentiate from side to side. Consequently, your test results are not a surprise.

You do not say what year your truck is nor whether or not your truck has a dual zone HVAC unit. This information would be helpful.

I have learned that the correct amount of refrigerant is critical in the earlier third generation trucks because of a baffle used in directing air passing through the evaporator core to the driver and passenger side of the cabin independently. Apparently this baffle is used whether or not the HVAC system is a dual zone. If the refrigerant quantity is slightly low, it will slightly change the location inside the evaporator core where the refrigerant changes from liquid to gas. This slight change of location does not allow the air to cool as much on the passenger side of the baffle.

There will always be some difference of air temperature from the driver side and the passenger side just because of ducting size and routing, but the difference should be within 5° or so.

So, if the refrigerant was not recovered and the system was not correctly recharged with the required amount of refrigerant (by weight), then this could be your problem.

- John

 

[evnizio]

My truck does not have dual zone HVAC
The A/C was charged by looking at the gauges and not by weight
Will look into that Thanks so much
Julian

 

[evnizio]

My truck does not have dual zone HVAC
The A/C was charged by looking at the gauges and not by weight
Will look into that Thanks so much
Julian.
That was it., inadequate freon charge THANKS

 

[evnizio]

That was it... Inadequate freon charge...Thanks.. Julian

 

[Ozymandias]

Needs to be charged by weight only. If charged by the gauges it will be over filled as this system acts differently than any other I've ever seen before.
Low side is in general 10psi or more lower then standard.

 

[jghflys]

This is the factory performance test. I use the setup and the bands below in the chart to add to existing charge. I get satisfactory results without evacuating the system.

A/C PERFORMANCE TEST

WARNING: REFER TO THE APPLICABLE WARNINGS AND CAUTIONS FOR THIS SYSTEM BEFORE PERFORMING THE FOLLOWING OPERATION. FAILURE TO FOLLOW THE WARNINGS AND CAUTIONS COULD RESULT IN POSSIBLE PERSONAL INJURY OR DEATH .

NOTE: When connecting the service equipment coupling to the line fitting, verify that the valve of the coupling is fully closed. This will reduce the amount of effort required to make the connection.

1. Perform the A/C System Performance Test found within the HVAC System Test. If no diagnostic trouble codes (DTCs) are found in the A/C-heater control or the powertrain control module (PCM), go to Step 2. If any DTCs are found, repair as required, then proceed to Step 2.
2. Connect a tachometer and a manifold gauge set.
3. Set the A/C-heater control to the Recirculation mode (max-A/C) position, the temperature control to the full cool position, and the blower motor control to the highest speed position.
4. Start the engine and hold the idle at 1,000 rpm with the compressor clutch engaged. If the A/C compressor does not engage, see the A/C Diagnosis chart.
5. The engine should be at operating temperature, the doors should be closed and the windows opened.
6. Insert a thermometer in the driver side center panel outlet and operate the A/C system until it stabilizes.

NOTE: The A/C compressor clutch may cycle, depending upon the ambient temperature and humidity.If the clutch cycles, use the readings obtained before the clutch disengaged.

#ad

 

[evnizio]

This is the factory performance test. I use the setup and the bands below in the chart to add to existing charge. I get satisfactory results without evacuating the system.

A/C PERFORMANCE TEST

WARNING: REFER TO THE APPLICABLE WARNINGS AND CAUTIONS FOR THIS SYSTEM BEFORE PERFORMING THE FOLLOWING OPERATION. FAILURE TO FOLLOW THE WARNINGS AND CAUTIONS COULD RESULT IN POSSIBLE PERSONAL INJURY OR DEATH .

NOTE: When connecting the service equipment coupling to the line fitting, verify that the valve of the coupling is fully closed. This will reduce the amount of effort required to make the connection.

1. Perform the A/C System Performance Test found within the HVAC System Test. If no diagnostic trouble codes (DTCs) are found in the A/C-heater control or the powertrain control module (PCM), go to Step 2. If any DTCs are found, repair as required, then proceed to Step 2.
2. Connect a tachometer and a manifold gauge set.
3. Set the A/C-heater control to the Recirculation mode (max-A/C) position, the temperature control to the full cool position, and the blower motor control to the highest speed position.
4. Start the engine and hold the idle at 1,000 rpm with the compressor clutch engaged. If the A/C compressor does not engage, see the A/C Diagnosis chart.
5. The engine should be at operating temperature, the doors should be closed and the windows opened.
6. Insert a thermometer in the driver side center panel outlet and operate the A/C system until it stabilizes.

NOTE: The A/C compressor clutch may cycle, depending upon the ambient temperature and humidity.If the clutch cycles, use the readings obtained before the clutch disengaged.

#ad

THANKS!!!
Yes,spent 2 days taking the dashboard appart!!!
Julian

 

[CharlesinGA]

My '03 factory shop manual actually has a caution that the A/C will blow cold on the drivers side and warm on the passenger side if undercharged (why I have no idea) and that is what mine was doing. When I found the note in the shop manual, I added R134a and sure enough it cools so good you could hang meat in there now!

Charles

 

[FOXY005]

Its a zoned system the top of the coil blows to the passenger side and the bottom to the drivers side, therefore low charge only cools the bottom section.