Hey guys. I'm having a hard time diagnosing an issue with my A/C. I've been reading through the forums, fixing things and replacing items as I go along but haven't nailed the root cause yet.

Symptoms: In hot weather, the AC does not blow COLD air. It's cool..ish. Not enough to cool the truck down though. Also, it worsens when the truck is at a stop light or parked. In extreme heat, the AC almost doesn't blow cold air at all when parked.

Fixes that I've done to date:
- Checked high and low pressures. Low is around 45-50, I can't remember exact high but it fell within the ranges that I found (175-200psi I think?).
- Replaced AC condenser clutch
- Replaced the hot/cold blend door actuator and confirmed it was working
- Replaced the condenser fan under the hood and confirmed it's working well
- Checked the outside/inside air blend door and actuator and confirmed it was working fine (cycled between max and normal air to confirm it opens and shuts all the way properly)
- Cleaned the EVAP under the dash to remove any dirt, leaves, etc
- Cleaned the condenser with condenser cleaner and hose

This weekend I was in the desert, where it was about 110 and the AC pretty much didn't work at all. Drove it back home where it was 90 and as the temperature outside dropped so did the ac inside. By the time it dropped to about 90 it was blowing COLD as I'd expect. Hoping someone here might point me in the right direction for the next thing to tackle. Did pretty much everything I could find on the forums and still no luck!

Thanks in advance

 

Sounds like your evaporator is clogged on the inside of the dash. I have not found an easy way to clean this without decompressing the system and taking it out. Or you might have a low charge in the system

 

Thanks @rtmtrrdr ! So clogged and preventing the refrigerant from flowing properly through the EVAP. Do you think there would be another symptom of that, like an abnormally high pressure reading on the high pressure side of the system? I'm not reading any abnormal pressures on the low or high side right now.

I'm not sure I'm familiar with what you mean by a 'low charge in the system'?

 

Low on refrigerant. Which is possible. I don't know what your pressures are supposed to be though....

I think he means clogged as in prevents airflow thru the evap core. Maybe.

 

@HeyYou thanks for the reply. So, I used a proper set of gauges to fill the system with refrigerant to the recommended PSI on the LOW side. Readings on the HIGH side were within spec as well so I don't think it's refrigerant. That was the first thing I checked. I'm pretty sure I ruled that out.

That's what I was thinking @rtmtrrdr meant too initiatlly, but the problem isn't air flow, it's air temperature. Air flow is great which (I think) means that there's no clog. I also got underneath and shined a light up into the EVAP area after taking out the blower and the blower capacitor to get a look at how dirty/clogged it was and it looked very clean to me. So I'm wondering if I can rule that out too.

 

Can you shoot the evap core with a temp gun, see if temp is uniform across the core?

 

You could also use an A/C dye kit to see if there's a leak.

 

Brought it in to my local mechanic this morning and he thinks it's the accumulator/filter given all the things I've already replaced and fixed. I purchased a kit with the compressor, accumulator and orphice tube and am going to install it and give it a go.