A/C Only Blowing Cold on Passenger Side

[loco_GT350]

Drove the 350 this morning and turned on the A/C for the first time this season and it is only blowing cold out of the passenger side vents (both of them). Both the driver side vents are blowing warm air. After my drive I went and checked the refrigerant levels and the system is on the low side.

I know I need to add refrigerant but not sure if low refrigerant will cause this issue or if it has to do with a blend door under the dash being stuck. Let me know if anyone has run into this issue before and if so, what was the cause it, and how did you fix it?

Also, does any one have a recommendation for a good electronic repair manual for these cars?

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[cerbomark]

I had it happen on a chevy once and it was indeed the low refrigerant cause warm air on the passengers side.

 

[Inthehighdesert]

You may check for a leak before you bring it back up. My mustangs have never had an issue with the blend doors. My 550 has to the point the control has been changed a few times which is a serious pain in the … . It has done it occassionally since but simply putting the system in the complete opposite setting has made it reset itself. On my 550 whens its has the hickups it has always been the ac stops blowing out the main vent and goes to the defrost vent and floor.

 

[G.T.]

I've had to replace a passenger side blend door actuator on my Mustang. Passenger side blowing hot.

EDIT:
But I've also had low refrigerant cause warm passenger side air on other cars.

The high side reading does seem to indicate low refrigerant. As already suggested I'd look into that first before suspecting the blend doors.

 

[matthewr87]

I just had this happen to my car a couple of weeks ago. I haven't investigated the cause of the leak though. I'm really hoping it isn't the evap core. My compressor has also been whining and groaning for the last year so I'll have to replace that as well.

I've just been driving with the windows down for now.

 

[dcalero]

I had this happen before on a 2015 acura rdx. We thought it was the blend door or that it was low on r134a. The culprit ended up being the expansion valve in the dash behind the glove compartment.

 

[lunatect]

Add freon

 

[loco_GT350]

I added some freon this morning and both sides are blowing cold so it looks like it was due to low freon. Now I need to keep an eye on it over the next few weeks and see if the charge holds.

 

[cerbomark]

was there dye in the freon? At least you ll easily be able to find the leak if you have one.

 

[loco_GT350]

was there dye in the freon? At least you ll easily be able to find the leak if you have one.

Yes, there is dye in the system from a previous repair a few years ago. I did check the engine compartment and did not see anything obvious with the black light but will check again more throughly if it starts blowing warm again.

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