AC issue

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SFROMAN

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There are plenty of 80 owners here so I hope I can get some much needed info on this.

I searched the 80 pages and was able to find a few threads with zero resolution and most were older threads.

The problem with my AC on my 97 lx450 is that it sometimes doesn’t work. I press the buttons and they light up and nothing. What I have down in the past is turn it on high and on and then turn the truck off and then turn it back on and it works again.

It seems to only work when the high button is pressed and or the automatic button is pressed. Hard to tell. the First time it happened was a few months ago but I didn’t care since the weather was cooler and I was using the heater anyway.

Also, when it does work. It works awesome. It blows super cold air with no issues or noises

I am hoping it’s a bad switch or a bad AC control unit. That would be an easy fix because I could just find a used one and replace the current one.

Any ideas?
 
Is there a high pressure switch in the 80 system? Could be not working due to pressure too high.
 
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Check to see if the compressor is coming on, it’s probably not. Check the connection at the high pressure switch(I think it’s near the dryer) also there’s a relay behind the glove box and ecu, it could be acting up. Next time it doesn’t come on check both of those spots, wiggle connection at switch and try to get to relay(pita) and tap on it. I don’t know much about those control units and how they are supposed to work, and how to diagnose those. Intermittent problems can kind of be a difficult. Besides just checking a few random things like the above, you’ll have to get the problem to occur and then systematically check for power at each point along the way.
 
Or strap a generator to the roof and stick a window unit in the rear windows, lots of duct tape and bungee cords make it work better. Super cold, cheap, and very classy.
 
Or strap a generator to the roof and stick a window unit in the rear windows, lots of duct tape and bungee cords make it work better. Super cold, cheap, and very classy.

I’m doing it
 
FWIW we had intermittent AC issue on Emma's 80 that was triggered by the engine running hot. Got the fan clutch replaced (w/ the right oil), brought engine temps down, and all was well. Does it only do it when it is really hot out so far? Could be the issue.
 
FWIW we had intermittent AC issue on Emma's 80 that was triggered by the engine running hot. Got the fan clutch replaced (w/ the right oil), brought engine temps down, and all was well. Does it only do it when it is really hot out so far? Could be the issue.

I have the digital scanner and after I changed the radiator when I first bought the 80 it has almost never been higher than 190F.
I also replaced the fan clutch when I replaced the radiator

I started the 80 this morning to see if the AC would work and it did.

I drove it this evening after it sat in the sun all day and it didn’t work.

I will test again in the morning. To see if the AC will work.
 
I have the digital scanner and after I changed the radiator when I first bought the 80 it has almost never been higher than 190F.
I also replaced the fan clutch when I replaced the radiator

I started the 80 this morning to see if the AC would work and it did.

I drove it this evening after it sat in the sun all day and it didn’t work.

I will test again in the morning. To see if the AC will work.

If you are staying under 190 that certainly isn't the same issue we had. I can't recall the exact temps, but well over 200 when hers was cutting out.
 
Fixed!!!!!

Replaced the control panel in the dash and AC is back to working cold as hell. Luckily the pick and pull had an lx450 I could get the parts from.

Thanks to Eric J. For the heads up and help.
 
Sad to report that I just got in the lx450 and the AC is not working again.

That sucks.
 
Well I figured that the little vent in the control panel is some sort of sensor since that’s what Eric said yesterday.
We blew into the vent with compressed air and it seems to have solved the issue.

It’s working again. Hopefully that is the fix. Just have to clean out that little vent every once in a while.

I will keep this thread updated.
 
I suspect that cleaning the little vent will not solve your issue, but I hope I am wrong. I'll dig through the archives to see if I can find the troubleshooting steps that I used, but I had the same issue on my 93 about 13 years ago and it ended up being the expansion valve. Relatively cheap fix, but had to have a shop do it to evac and recharge the AC.

From my admittedly supect memory, If the AC is working fine, but intermittently, your refrigerant levels are likely fine, the compressor is likely fine and your condensor and evaporator are likely fine. If you start it up after sitting for several hours and the AC works for 10-30 min and then quits, it points to icing in the expansion valve.
 
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I suspect that cleaning the little vent will not solve your issue, but I hope I am wrong. I'll dig through the archives to see if I can find the troubleshooting steps that I used, but I had the same issue on my 93 about 13 years ago and it ended up being the expansion valve. Relatively cheap fix, but had to have a shop do it to evac and recharge the AC.

From my admittedly supect memory, If the AC is working fine, but intermittently, your refrigerant levels are likely fine, the compressor is likely fine and your condensor and evaporator are likely fine. If you start it up after sitting for several hours and the AC works for 10-30 min and then quits, it points to icing in the expansion valve.


Once my AC is working it doesn't stop working. it wouldn't work when I would start the truck.

I did replace both the control in the dash and the "controller" "sensor" under the glove box.

it immediately worked once I changed those out but the next morning it wouldn't work again.

That afternoon we blew air into the vent and has been working perfectly fine since.

keeping my fingers crossed.
 
B0670724-1CDB-4242-969F-4F8D14A8F0C1.jpeg


This is how I really fixed the AC.

HAHA!!
 

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