I have a 1990 2 wheel drive PU. the air conditiong worked fine on the way home, next day no cold air. Never have had any problem whatsoever before. Coldest air conditioning I have ever seen actually. I have checked the fuses, ac fuse and heat relay fuse, all OK. The clutch does not engage when switch is pushed. I had similar issues on Chev 4x4 and had to replace low pressure switch. Easy and cheap fix. I have tried to access the switch but can't get to it. Does replacement of this require removal of entire evaporator?? Thought I could just get the cover off but doesn't seem to want to come off. Will I need to recharge unit to do this? My chev was just a simple part replacement. Thanks for you help. Charb

 

does the ac backlight come on when you push the button??? ive had problems with other switches that just needed a clean. check the connection to the pump too(all the way in and not all greasy dirty from a leaky P.S. pump leak. long shots, but better check the easy stuff first before having all sorts of fun tearing in.

 

You may just need to recharge the system which is easy and cheap. You may have worn a hole in one of the lines too. My old '91 3.0 4runner did that and I recharged the system. It started to vent out a hole in one of the metal lines as soon as I started recharging it, so I changed it out, recharged it again and it was good after that. The line got loose and was rubbing on something until it got too thin in that spot and busted open.

 

Yes, the switch light is illuminated. Don't know if that means it actually working or not? Thought about checking that switch next. Not much of a mechanic but I always give it a try before taking things to a shop. I have an actual Toyota manual but it is for 1988 models and mine is a 1990. It says there is a sight glass on the receiver by the radiator and to look for bubbles but I sure can't find it. Both lines to the compressor are hot to touch when I feel them with the switch on. I didn't think I could lose all the refrigerant over night after all these years but maybe so. Thanks for your help and suggestions, I will keep trying. Charb

 

It sounds like you have a leak somewhere. Find the leak, fix the line, then recharge it and you should be good to go.