The drivers side blows cold, passenger side does not?

JOEV65

MEMBER
2005 CADILLAC STS
3.6L
6 CYL
2WD
AUTOMATIC
91,000 MILES

My drivers side blows about 60-degree air, however, the passenger side either blows hot or ambient according to the temperature selection. It will not blow cold. I checked the blend actuator, and it is moving the blend baffle full range from hot to cold. Low side pressure is 55 and high side is about 150 (too low?) The ambient temperature is about 85 degrees. Totally stumped!

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

At 85 degrees, the low side is good, but the high side is low. It should be 220-250 psi. Usually, when the high side is too low, the system simply is low on Freon. However, it can be an indication of a failing compressor.

Interestingly, the low side is at the highest point for the outside temperature. Have you tried recharging it?

Another thing is the idea that one side is cold and the other isn't. If the actuator is working, that makes things more confusing. There is only one evaporator core, so if one side is cold, and the actuator is working, it too should be cold.

Can you see the blend door moving when the actuator moves?

Let me know.

Joe

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Saturday, June 24th, 2023 AT 10:45 PM

JOEV65

MEMBER
2 POSTS

Hi Joe,

Thank you for your reply. Turns out that it needed refrigerant. The pressures are now 50 low and about 190 high at 85 ambient and both sides are blowing cold. I was confused because there is only one evaporator so how could only one side be cold; however, I realize that when refrigerant is low, sometimes only part of the evaporator gets cold.

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Sunday, June 25th, 2023 AT 10:19 AM

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

That is good news and thanks for the update. I'm glad it was something simple and not too expensive to repair.

Take care and feel free to come back anytime in the future.

Joe

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Sunday, June 25th, 2023 AT 8:46 PM