A/C issue… I’m stumped

Ok so I have a 2017 Trd OR 4x4. My A/C stopped working randomly. I checked the relays and all related fuses and they are good. The compressor is good, the Freon is full and at the correct psi. The fans blow air great I even bought a brand new switch panel from Toyota. Here is the weird part, the A/C blows ice cold air only after I wash my truck

HELP!!!!!!!

 

Did you check refrigerant with a gauge set or just a parts house low side gauge?

Define 'stopped working ramdomly' with more specifics.

Why did you buy a new switch panel?

Is your condenser clogged with junk (related to the after I wash it comment)

 

i didn’t use it for about 2 weeks when I went to turn it on it didn’t work. It was checked by a buddy of mine with all the equipment. He also checked the relays and fuses. My condenser isn’t clogged as I don’t go in mud and after I hit any trails the truck gets a good wash. I bought a new switch panel because I had credit with the dealership so used it thinking it might be the switch’s.

I have tried using it and it blows air but doesn’t get cold at all. I wash my truck on Friday after I get off work and after each time the A/C blows ice cold air and stops being cold about 30-45 minutes later it’s a 30-45 minute drive home from where I work and wash my truck.

 

Is there a bit of fog or smoke looking discharge at the vents right before the cool stops?

When the cool stops does the vent output reduce in volumn even though the blower still sounds the same?

 

Just tossing my hat in the ring since I'm bored.

Perhaps check the air intake outside at the base of the windshield, if it is blocked with crap or a dead mouse there will be less airflow which means less air blowing across the condenser to vaporize the refrigerant which means it will start out blowing cold and then after 15-20'ish minutes it will slowly start getting a bit less cold until finally there is no vaporization and thus only outside air temperature will be blowing in. Washing the vehicle may flush just enough of an opening in the ducts to allow more air in and after the crap in there dries out they start to clog back up. Maybe use a wire hanger and *carefully* poke around from the outside, making sure you do not puncture the ducting.

But this is just a guess, of course. YMMV.

 

Did you ever have the AC recall done?

https://static.nhtsa.gov/odi/tsbs/2020/MC-10181775-9999.pdf

 

Volume is still the same when the cool stops. No there is no vapor or fog when the cools stops.

 

When the cool stops is the AC compressor still turning or is the clutch in the freewheel mode?

 

I haven’t checked that but I will when I wash it again lol.

 

Do you wash it indoors? Perhaps it's a humidity/sensor issue.

 

Hook a scanner to it. B1422 code probably exists in the AC amplifier.

Otherwise, start the truck and spray the condenser with a garden hose and see if cooling stays consistent.

If everything is working, low side is sweating, high side warm/hot and you're still not cooling, you probably have a blend door issue. Have you attempted a hvac calibration by chance?

 

I will try a scanner when I get into work tomorrow. I have not done an hvac calibration.

it rained on Sunday and the A/C blew super cold air lol

 

Need to see if the clutch on the AC compressor is engaged when the AC cuts out. That will allow you to further isolate the problem. The wider rubber low pressure hose near the firewall should also be pretty cold. Could be a bad compressor, refrigerant level, pressure switch, a damper door, even a heater valve. Less likely is the actual controls though. Find out if that clutch is engaged and get back to us.

 

OOOO! I know this one!

So on your compressor there is a ground wire, its on the top of the compressor and goes behind the clutch. This wire is not protected at all and will corrode, when it does the compressor will not ground and it causes it to not kick on. When you wash your truck, the water gets into that wire and is just enough to complete the circuit.

The fix toyota did for me was to replace the compressor, but if you cut that ground wire back enough to get clean copper, you can solder on a new wire and ground it. After you replace it, smother it in dielectric grease.

This is the ground wire

 

Hold the auto and recirc/fresh air buttons. At the same time and while holding switch the ignition to the on position and it will first do a bulb check then it will display hvac codes. 00 is the all clear and anything else is an issue. Without personally reading the gauges myself it's hard to say but I would guess it's a txv valve issue but you should first off see if the compressor is running still when the air warms up.

 

what if you don't have the "auto" button?

 

My 2016 started blowing slightly warmer thru passenger side front vents than via the driver's side front vents about 2 months ago when the heatwaves hit my area.

A/C performance when its really hot outside with the truck A/C in the non-recirculate mode also started to degrade some.

They could not identify an obvious refrigerant leak. So they added dye to the refrigerant and charged up the system and told me to use the truck normally and come back when the A/C performance starts to deteriorate once again.

This is the first time in the truck's life (2016 build with 72k miles) that the A/C system has been touched. They told me it could take 1 day or 1 year for any type of leak to manifest itself, all depends on the size and location of this would-be leak.

To you A/C and HVAC nerds....does this sound like legit info?

 

OBD port is the only option then.

 

yea, that's pretty standard. mine still blows cold but not as cold as when new. i need to get it charged up. my a/c gets used a ton. i do deliveries so i'm constantly getting out and having to crank the a/c to cool down.

 

Interesting! I was thinking electrical connection when I was reading about car wash and rain causing it to start working temporarily.