I have a 1995 toyota 4runner 4x4 with a 3.0 auto. My problem is, that the A/C just stopped working for about 3 miles. When I got home, it was still not working. From out of nowhere, it started working again. Any clue to why it would do this. All my fluids are good. Also, is there a fuse to any part of the A/C that would cause this? Thanks for the help.

I need to no ASAP as I'm taking a trip tomorrow and don't want to have a problem on the way in what happend today.

Thanks again.

 

Anyone?

 

What fluids are ok? Did you check the refridgerent in the a/c?

 

Yes there are fuses, but if one was blown, it wouldn't have started working again. Check for leaks, and try charging the system.

 

Evaorator FROZE solid.
Pressure switch kicked in to save the compressor...

Possible freon/R134 issue (low) or Thermistor issue? (wild guess I dunno AC at all)

Thermistor is supposed to shut the compressor so that the evap doesnt freeze up...

 

No I didn't check this as not quite sure of how to do so. But if it was low, why would it start working again. Its worked fine for about 1/2 hour after it started working, and when I sut off the rig, it was still working fine. I will no more and if it is still working when I go to work. Just seems strange that it would stop working for about 3 miles, and then just start working again. If there is a saftey shut off somewhere that would be good, but I don't no anything about it at all. I guess if it happends again, I will take it to a shop unless you all can come up with something I should look for, and how to check.

 

I have an 89 with an R12 system

It was a "port" kit installed by the dealer (when the truck was new)

IMHO the systme is "too small" as AFAIK the same kit used for the trucks and the 4Runner has more internal volume to cool...

Check the FSM - I think there's a sight glass to check for bubbles.

Also get a "meat" thermometer from a good cooking store.
Stuff it in the vent and read off the temp of the cold are that's blowing.

What you want to know is
-- how cool it blows when its working
-- how "hot" it gets when it "shuts off".

Mine was recharged in the late 90's (about 40% empty?) and again recently (took only 2oz or so).

Even now the evap tends to freeze up and it starts blowing at 50 deg when its been working for 2 hours (aka road trips). When cool it can pull down to 40 deg..

Shop suspects a faulty thermistor - but left that for me to check (its OK - its a good shop and they knew that *I* can trouble shoot the thermistor for far less than paing them to trouble shoot it)

 

How do I check the thermistor? and do I check the FMS for bubbles when it is running. If I do see bubbles, what does this mean. Thanks again for your help.

 

FSM = factory service manual

I dont have it handy..

I recall that bubbles meant coolant (freon/r135a) was low

Thermistor is in the evap box - should have its own plug.. FSM should have resistance measurements - my FSM doesnt last I looked...

 

2-60 Air

 

had both of my past toyota trucks (87 and 90)do exactly the same thing.

it must be something that freezes.

mine would only do it on the hottest most humid days after about 2 hours of city driving. after 15 or 20 minutes shut off, everything back to normal.

it could be worse, and be like my volvo, which needs recharging every summer it seems.

 

OK I got up this morning, and from a cold start, no A/C, so I don't belive it is something freezing up. After a few trys, it started working, but I don't no for how long. I really don't no what to do at this point. I don't think it is freon, or it would not start working right. Any other idears?

 

is your motor idling up when the compressor kicks on? if it isnt its electrical, like that pressure switch underneath the passenger side glove box. little cylindrical silver thing. cost about 10 bucks i think. mine did the same all the time for about 6 months till i finally figured it out. had an electrical plug at the very back of the intake plenum coming loose from its connection. if it is low on freon it will freeze up, and should be the same results as overcharging the system. hope this helps, tim.

 

Is yours also a 1995 3.0? You talk about a pressure switch underneath the passenger side glove box, is this what I should check, or should I check the electrical plug at the very back of the intake plenum. If it is this, any idear of where to look at the plenum like what side, color etc. As you no, it is tight in there.

 

1st question is: Does you motor idle up when the compressor is on?

 

Only when it is working it will do this. Other then that, the compresser isn't going on.

 

then it sounds to me that your air condition works great when it does.. has to be electrical i would think. find the pressure switch and replace it with another one. i'll stay tuned. this happens all the time on older chevrolet pickups so i assume it could happen just the same in this instance.

 

take ur ac gauges out and ck pressures 30-10 psi low side 175 to 275 high side

 

sounds like expansion valve is sticking if so lo side pressure will pull into vaccum seen problem several times / possible low freon level causing evap core to freeze to

 

On a properly charged system you will see bubbles when the compressor first kicks on, but they should clear pretty quickly. When the compressor kicks off you will see the bubbles come back, and then the sight glass will appear empty....this will happen over and over as the compressor cycles. If you see bubbles continuously, then the system is low on refrigerant. If you see no bubbles, but oily streaks, the system is empty.

While the sight glass is helpful, it is not the most accurate way of measuring the refrigerant level.

Sound like you may be freezing up as some have mentioned, or if the engine is overheating it can also cause the system to kick off until it cools back down (but your cold start experiment makes it sound like these are not the problem). Something is kicking your compressor off...