a/c stops cooling at times
 

hey guys,
need help with 94 4runner a/c.at times after driving for 5-30 minutes ac stops cooling,still blows fine just not cold,has new expansion valve & drier,also has new ac amplifier on evap housing.seem to be losing power to clutch.light in ac switch stays on when stops cooling.shut rig off a few minutes & ac me cool again for a while,anyone else been here? :(

Same here on my 95.
I talked with a Lexus expert and he indicated that there were shut offs built in, but I do not think the runners are that advanced. With that said, I still think it is still a cooling issue since our runners are notorious for overheating issues. Sometimes mine works when it is very hot outside and I get really cool air, then at various times it just shuts off but with the light on as yours.
I just ran into a problem with the timing belt tensioner - falling off - so I am hoping it is my problem. You will want to check all the belts for tightness and check your timing belt tensioner for any loose bolts. Keep me posted on your findings - I think we can get to the bottom of these - there are so many posts about it but no answers. :bang:

Try to replace the idle air control valve, mine shuts off when you are stopped, like at a red light, but once you get going, it will freeze you out. I know its the problem with mine, but I can just hold my foot on the gas pedal ever so slightly and it does what the IACV does automatically, adjust the idle for strain on the engine!

I cleaned my radiator and AC radiator with a pressure washer and it made a big difference in traffic light cooling.

doesnt necesarily stop cooling at idle,can be driving down the road,next thing ya know ac blowing warm air

Could be a sign of too much freon.

my '95 3.0 did the same thing
was a clogged evap filter if I remember correctly.
Works great again.

yea i am in dallas and with it being 100 degrees out side mine blows around 65-70 even if my 95 runner is over the normal operating temp...

How does one go about cleaning the evap filter - it would be appreciated. Although I have other concerns with my runner right now, I will want to try anything

Yup sounds like too much pressure.

sounds like either to much freon or the condensor could be partilly clogged gousing it to build to much pressure and shutting the system down.

i think i found the problem today,got to studying the wirng diagram,found a water temp sensor switch that goes to an ac cut relay,after investrigating the wiring at the switch found just a strand or 2 making connection,could make the compressor shut of by moving the harnes,then the wires broke off completely,going to install a new switch & new connector,hopefully the mystery will be solved

Good luck littlerunner and don't forget the photos. Keep us posted. I am traveling home on Saturday and will begin my timing belt PROJECT next week. After that I will tackle my A/C problem - with your help, perhaps mine is the same.

check this out (it's just an online fsm you guys have prob seen before)

go to the a/c section and look at troubleshooting.

i was reading it and maybe check into magnetic clutch slipping etc. read through it all; it's some very useful info.

That is great - thanks Tdubbs05. I can only reach the index however, can not reach the pages to check wiring, clutch, expansion valve or amplifier. Love your snow photo.

put a new connector on the water temp switch tha tgoes to ac cut relay,had a case of the green funk on the old one,so far so good,we'll just have to see how it goes

Make sure the lines are not freezing up. Sounds like its low on freon or 134a but anyway when you start to take off the warm air going through the engine bay is
defrosting the system. That is my experience.

same issue?
 

I may be having an issue as well, but I'm hearing two separate issues (in the thread) and even more solutions.
I'm experiencing loss of cooling when at idle. As soon as I get going again it starts cooling just fine. Is that a tentioner issue, or over/under filling of Freon? Thanks guys!

PS I have a new compressor and evaporator running 134a

I'm having the same problem as littlerunner with my 97. Everything seems to work fine then nothing just warm air. It doesn't have a pattern can happen at any time, idle, cruise, and even at initial startup. I'm just started searching YT and can across this thread. I figure I'm going to have to start testing the components and wonder if someone could tell me if the post by Tdubbs05 to the FSM on a 1993 applies to a 1997 air conditioner?

Littlerunner: I hope it is as simple as a loose or corroded wire. My first impression is it’s a simple/easy fix as when it’s working it works great. I just had the system charged in an attempt to solve this thinking low on coolant but not solved just frosty when working.

Here is why I think my timing belt issue was the cause of my A/C problem. My tensioner broke off, so there is no telling how long it was not performing. Just below the tensioner pulley is the A/C clutch and belt. If it was slipping, the clutch would not have been performing or slipping only at certain times. If the problem is intermittent like mine and littlerunners, they are likely wire or connection issues. I ran mine off and on about 10 times and can not get it to repeat my problem after my timing belt change. The next parts to check according to the troubleshooting document are all behind the glove box - that comes out today.