A/C Troubleshooting... before I go buy the tools

[jumpjet]

T4R,

I'm trying to see if I missed any initial troubleshooting steps before I go buy gauges and a vacuum pump to do it all the way.

Symptoms:
It's a 2005 V6 SR5/4WD. Following a multi-day road trip towing a load, the 4R sat for a couple days. On the next drive, the AC was blowing ambient air, regardless of setting (tried in Auto and LO). The AC light was not blinking. Visually, the compressor clutch is engaging/disengaging depending on selecting the AC on or off. This leads me to believe the relay is ok. There is a small blackish/burnt-looking spot on the corner of the relay (pic attached), but googling seems to tell me that's normal.

The sight glass looks like this:
4Runner Sight Glass Video (should be a link to a 5sec video of the sight glass during AC operation). Which tells me there's at least some refrigerant in the system.

The next steps seem to be getting my hands on some gauges to check the pressure, then draining and filling the system with dye to check for leaks.

Am I missing any other potential obvious cues?

Thanks in advance.

 

[Auditechnician]

Your process sounds solid. Sight glass definitely looks low, but that the compressor is still functioning. If you can’t find any leaks in the system, it may have purged through the relief in the compressor if pressure got to high during your trip. Of course I’m just speculating Toyotas even have relief valves in compressor (I know a lot more about Audi design than Toyota).

 

[vipergrhd]

Check line

If the compressor is cycling on/off check your low pressure hose/line if it's cold,cool or just ambient that will tell you if your issue is with your A/C system or an issue with the controls inside the cab. Since you mentioned you have an Auto feature you likely have actuators that control your doors for the housing directing the air out of your vents.

 

[Captsolo]

I have a SR5 2005 (150,000) miles and had to replace the AC Compressor after 12 years in Bahamas where it ran 24/7. Have it dye tested for the leak. Forget fixing the clutch. Get a new Denso at Amazon for $200.

Amazon.com: Denso 471-1413 New Compressor with Clutch: Automotive

DENSO IS THE OE SUPPLIER FOR THIS VEHICLE, w/NEW COMPRESSOR, OE-SPECIFIED O-RINGS AND OIL INCLUDED

 

[eleven14]

If the compressor is cycling on/off check your low pressure hose/line if it's cold,cool or just ambient that will tell you if your issue is with your A/C system or an issue with the controls inside the cab. Since you mentioned you have an Auto feature you likely have actuators that control your doors for the housing directing the air out of your vents.

Having a similar issue, what do the various temperatures on the low pressure line mean?

Symptoms
• The last few nights after I shut the truck off, I hear a hissing/breathing sound from behind the dash. AC is on when vehicle is shut off.
• Tonight it was blowing cool (not cold) air (very high humidity in the area, temps in the mid-80s, truck had been sitting in the sun for an hour +)
• Tonight I turned off the AC before shutdown and heard no hissing/breathing sounds
• Noticed a larger than normal puddle of water/condensation from the AC under the vehicle

Any AC experts have thoughts on where to start? Thanks in advance

 

[jumpjet]

Finally got around to picking up a set of gauges and a vacuum pump. Static pressure on the system with the engine off was ~30psi both sides. When the clutch engaged on the compressor the low side pulled a vacuum and the high side only went to about 60psi. Since it had a static pressure that didn't seem to indicate a leak, I figured the worst that could happen recharging it would be that I'd be out the $16 for a couple of cans of 134a.

Pulled a vacuum and let it sit for a while with no apparent leaks. Vacuumed it down again for another 30 minutes, then put two cans of 134a in and a 1/4 oz of dye. The system capacity is a hair under 24 oz (23.98 oz according to FSM). Blowing cold again for now. If it holds, great. If not, I'll fix the leak if I can find it. If it's under the dash, I may try some leak stop until it cools down and I feel like tackling that pain in the ass.