Black31385

Hello, I have an issue with my a/c. The left side blows out air but it is not cold. The right side is cold. The whole front dash has 4 vents total so the left two does not blow out cold air at all. Any help is appreciated

ELITech

What year is the car? How many miles? Any A/C work ever been done?

Black31385

It is a 2007 with 86,000 miles. I had this issue before I had a minor accident. When I brought it to a local shop to get fixed I had told them about this issue and they told me that they can fix it for $300 dollars. They told me that I needed some part. So I agreed with them to fix it. About one week after receiving my car back the issue came back and they told me I had to put out $70 more for another part that went bad. They told me it is a completely different issue.

ELITech

The first thought that comes to mind is that the A/C is low on charge. While this sounds odd, low refrigerant levels can create a temperature difference between driver and passenger side.

I would've suggested a possible servo motor bad, but in 2007, the ES had it all built into one unit if I remember correctly. I know the newer ones have...

So I would have a place you trust perform an Evac & Recharge of the system. Have them put dye in the system to help detect the leak. Typically it will be the Evaporator. But not 100% guarantee.

sy09es350

Hi I have a 09 ES 50K miles and its doing the same thing. Driver side vents blowing air not cold but the center passenger vent is blowing the coldest. Passenger side vent near the window is not as cold either. Suspecting the air mix servo, I removed the driver side airmix servo and cleaned the contacts + re greased. The contacts looked very clean. potentiameter contacts looked like it was electroplated gold.

I put it back on the car and watched the gear move the damper arm end to end as I set the temp control from lowest to hottest. Servo moved it incrementally end to end like it was supposed to so its not the servo.

My next step is to take your advice and take it to the dealer and ask for a refrigerant charge. how much is a reasonable cost for this?

sy09es350

Just got off the phone with the lexus service advisor. (Pohanka Lexus is open 365 days a year). He said not likely low on charge if passenger side is blowing cold. He also said when blowing cold only on one side 99% of the time its the air mix servo motor.

The thing I dont get is that the driver side is not blowing cold air even when the warm air gate is fully closed. (I am looking at the geared arm the servo motor lift to let warm air mix,and it is fully shut, therfore I concluded the servo motor is working)

ELITech

I think the '09 ES has everything built into one servo if I am correct. Not trying to argue with an advisor a thousand miles away, but from tech experience, low charge can cause issues between driver and passenger side.
.
Now depending, the '09 es has a customize setting where you can differentiate the output temp on passenger side and driver side each by 2 deg celsius, +/-

So the driver side could be putting out +2 deg C over what display says, and passenger side could be -2 deg C over what display says. But if you haven't had that changed, having the Evac & Recharge done is the smartest starting point, so you know the charge is the correct amount.

sy09es350

Thanks ELITech I'll tri Evac-and Recharge. I didnt mean it to come across as the advisor said you are wrong just reporting what he said.

Regarding temp difference when charge is low, could it be that the driver side vent is down stream from the passenger and the rear vent and it is getting air couple degrees higher. wondering if I didnt notice the temp difference before because it was cold enough in all vents when charge was in spec. Now that the charge is low the temp increased in all vents plus the weather is much hotter?

Thanks ELITech we are lucky to have you on the Forum.

Black31385

On my car the right mid vent and passenger vent is cold. The driver and left mid vent is not cold. Could this be the air servo issue?

ELITech

I didn't think you were implying the advisor said I was wrong. It's one of the first things I learned in our HVAC class. Start at the easiest most obvious point and go from there...

The vent placement isn't that much further from the evaporator. It has to do with the travel of the r134a through the evaporator. Think of it this way. On a hot day, if your hose has been in the sun, you turn on the faucet and immediately get hot water. As the water that was left in the hose during the day exits, it slowly cools down to cool water. Kind of the same concept except in reverse. The r134a enters the evaporator. It sounds weird but the purpose as it goes through the evaporator is to take away heat from inside the car. Well if the charge is low, then the r134a heats up quicker because there isn't as much to absorb heat. So by the time you get to say the half-way point, the r134a has already taken as much heat away as it can. That part of the Evap is on the driver side, so the air moving across the evap on that side which goes to the driver vents doesn't get as much heat taken away...

Hope this helps to understand roughly what is going on

ELITech

I would start with an Evac & Recharge first.

Black31385

I would just like to update this post as I do not want to leave it un answered. I did get the a/c recharged and now the a/c blows cold evenly. I guess it was low on charge so it blows uneven. Thanks everyone for their help

Lexi66

Question,,, did Lexus dealership perform the charge? If so, curious what they charged?
Thanks!

mcomer

ELITech, Thanks, love a good analogy!

Black31385

I did it myself