AC Problem: Blows HOT unless on "LO"

[gjv200]

On a road trip from PHX to LA last week, my AC started acting odd.

If I have it on LO, it will blow cold as usual.

But on any other setting (64, 65, etc)... it just blows hot. Not warm, but HOT.

Fiddled with all the settings, and it always ends up the same.

Going to get it serviced in a few days, but wondering if anyone had experienced the same issues and had any knowledge on it!

(Apologies if this has been addressed earlier; I couldn't find a thread on it in my search.)

-G

 

[xtremewlr]

Sounds like a possible failure or failing of the blend door servo. Sounds like the servo isn't working to keep the door closed from the heat side, allowing or moving the door in the wrong direction and directing air thru the heater core. Search for threads on the HVAC servos, they might be able to help you determine which one to check.

 

[Captsolo]

I think it low on freon.
I have 2005 4runner.
AC lasted 10 years from new - than troubles.
You probably have a leak in the compressor - or need a replacement evaporator (front dash area).
Have them put dye in when they recharge with freon.

I'm in the process of getting my AC up again in my 4runner.

Initially, a shop wanted $800 for the labor. Now they are at $300. I provide the part.

Dealer wanted over $1000. I checked the records and they replaced an evaporator core in 2009.

I replaced the compressor once and had good ac for two years.

I suspect and hope it's the evaporator this time.

 

[ads2539]

On a road trip from PHX to LA last week, my AC started acting odd.

If I have it on LO, it will blow cold as usual.

But on any other setting (64, 65, etc)... it just blows hot. Not warm, but HOT.

Fiddled with all the settings, and it always ends up the same.

Going to get it serviced in a few days, but wondering if anyone had experienced the same issues and had any knowledge on it!

(Apologies if this has been addressed earlier; I couldn't find a thread on it in my search.)

-G

I and many others on this forum have had the exact same problem - cold air on lo, but hot everywhere else. It’s a simple fix, and free!

Your cabin temperature sensor is unhooked. It’s under the dash to the right of the steering wheel. I had my dash apart, and accidentally unhooked mine. After hooking it back up, my A/C worked normally again.

Do a search for “4th gen cabin temperature sensor”, or something similar. I searched for “a/c blows hot” and found it, but there were some threads about other issues. There are a bunch of threads about it. This forum saved me from having to pay someone to fix my A/C.

DO NOT pay your dealer to look at your A/C issue. It’s a free 15-minute fix. Your dealer might charge you $100-$200 to fix it, between diagnosing and solving the problem. Or worse, they could charge you $1,000 or more to replace parts that aren’t broken. If the A/C system works normally on lo, then it works. Nothing in the A/C system is broken. It’s your cabin temperature sensor.

 

[xtremewlr]

I and many others on this forum have had the exact same problem - cold air on lo, but hot everywhere else. It’s a simple fix, and free!

Your cabin temperature sensor is unhooked. It’s under the dash to the right of the steering wheel. I had my dash apart, and accidentally unhooked mine. After hooking it back up, my A/C worked normally again.

Do a search for “4th gen cabin temperature sensor”, or something similar. I searched for “a/c blows hot” and found it, but there were some threads about other issues. There are a bunch of threads about it. This forum saved me from having to pay someone to fix my A/C.

DO NOT pay your dealer to look at your A/C issue. It’s a free 15-minute fix. Your dealer might charge you $100-$200 to fix it, between diagnosing and solving the problem. Or worse, they could charge you $1,000 or more to replace parts that aren’t broken. If the A/C system works normally on lo, then it works. Nothing in the A/C system is broken. It’s your cabin temperature sensor.

Very good suggestion here. I completely forgot about the cabin temp sensor. Definitely check that out first!

 

[Warwicke36]

And even if its plugged in check to make sure it's clean... Mine was dirty and made it function erratically.

 

[ads2539]

It’s a common issue after taking apart the dash for stereo work, etc. I had just replaced my stereo’s head unit.

Here’s a photo I stole from another thread about the cabin temp sensor.

The plastic tube and clip both need to be connected to the sensor.

 

[Montego Murph]

While you're poking around in there, make sure the vent isn't caked with dust and fuzz, and gently blow off the temp sensor.

There is a slight vacuum on the sensor line and it sucks in all sorts of gunk. Once the sensor has a nice dusty coating, the dust insulates it and the temp selected will rarely match up to the actual car temperature!