I seem to remember this happening last year as well, but it must have started working again as I don't remember doing anything about it. Or I just drove so infrequently the past year that I didn't care? I usually drive with the windows down around town anyways, but AC is pretty key in keeping the ladies happy on the highway.

I've converted to non-nav and an aftermarket head unit in my '04, so normal diagnostics via nav-display are not available to me (that I'm aware of). I tried hooking up the tech stream today, but couldn't find any options for HVAC related diagnostics in the software. Anyone know where I should be looking? It's SOOOO slow on my old laptop running VM, and it was hot out there, I feel like I had a pretty thorough look, but came up empty.

I can confirm visually the AC compressor clutch is not engaging at any time, I ran the truck in the driveway on MAX COLD for 20 min today and it didn't engage once. I turned on the rear AC and no change either.

I suspect it's low on refrigerant...I did hit a deer a few years back which could have caused a slow leak. But there's got to be a way to troubleshoot and confirm if that's the issue before going and having refrigerant added, is there not?

 

i'm no AC expert but my past experience is that the compressor clutch will not engage if there is no pressure in the system. see if you can hook up a gauge to one of the low pressure lines and see if there is pressure.

 

Buy a bottle of AC charge at Walmart that comes with a guage. Easy $30 diagnostic. If it’s just low, fill. Either way, you have a guage.

 

My experience with this same issue was that my system was low on refrigerant. The clutch not engaging is another sure sign.

save your money on the junk stop leak big box refrigerant cans. I have found them not reliable for long term AC performance. I went through several cans over a couple of years before taking it to the dealer to charge the system. They will also put dye in to detect for leaks.

 

Agree that you need to take it to an A/C specialist that will use dye to look for leaks, and will pump the system down before refilling with the correct amount of refrigerant & oil

Chip H.

 

Got over to see my buddy to try and top up the refrigerant, found the low side schrader valve appeared to be leaking a bit, messed with that and got it to hold, put the system under vacuum, and then refilled with refrigerant. Blowing cold as ever again!

Glad it was a cheap/easy fix! If it leaks down again, I'll add dye and find/fix the leak permanently, for now I wanted to confirm that low refrigerant was actually the issue.

 

Always best to gauge it and take the temps of the lines to see where it's at, to determine if it's a leak or something other.

Low 134a, clutch not engaging, and a diverter door that fails to close fully on the cold side, can all cause cold-air issues.

Mine may have expansion valve issue. With proper charge I am seeing normal hi-side psi, but lo-side is a bit too low.

 

Another tip:

If the AC system keeps going low, then I recommend you change out the schrader valves (one Hi side, one Lo side, see post #6).

If you do a quick twist 'off' of the caps and hear a phfffftttt sound, the valve is likely leaking just a smidge, and over time your system will go low.

 

Well my last charge lasted 7 months before the system leaked out all of the freon and started blowing hot air over the weekend.

Back to the dealer for another charge and dye. This time it lasted a week before it started blowing hot air, leaked out FAST.

Back to the dealer yesterday to hunt down the leak and unfortunately I have a major leak in my evaporator - the most expensive thing to fix, just my luck. Lots of labor removing the dash and evaporator. Quoted $2100 parts and labor but my SA is going to get that down since I'm a good customer of the dealer, plus detail inside/out the GX for me. I could likely save a few bucks shopping around but this repair is very labor intensive and I have the utmost confidence they wont damage any of my plastics and everything will be put back together to spec.

Getting it back Monday.

 

Nothing wrong with an easy fix at all ! Had to fill my 09 F150 last year , still freezing the ladies nice! Now if I could just my wife to put the gas cap on my GX the right way! Had to disconnect the battery for a while again!

 

Unfortunately the "fix" only lasted about a week, I'm back to sweating my ***** off, lol. Leak test is the next step and we'll go from there.

 

Got the GX back today from our Lexus dealer. A/C works like a champ now! My dealer knocked 10% off the bill. Total cost for new evaporator, expansion valve and some O rings $1,842.

 

Dang... my GX's air conditioning wasn't cooling like it did a week ago! I hit a ramp or a bump and I got a small blast of cold from the system. Really it took 30 min to feel just ok on full blast.

Dropped it off at the Mom and Pop Garage School bus station we use for service. Almost cost me $100 to make the cold freeze my face again. What's the world coming to? 😜

Crossing my fingers that it holds this charge,

 

??
Are all the fittings on hoses to/from compressor and condenser tight? A bounce should not cause a leak.

 

The leaning and bumps probably helped move the coolant around that was still in the system. I figure it was 1/2 way empty
So they purged and refilled to correct amount on the pressure gauge. The 2 days prior we had 90+ high humidity and it took 30 min to get the cab down to 80. So it did have something left. Now its as good as new.

Had a guy at work complain his heat was blowing hot then cold. I asked him when was the last time he checked his antifreeze. He said that's not it ! I just had it serviced. he took it to his garage and they put in 1.5 gallons of coolant.

I know we put a gas into our AC units, but I think low levels give us signs if we pay attention.