A/C compressor won't engage

[arracado]

Lesson learned...even if it's a cold day outside when you're test driving a vehicle...make sure the A/C works!! Anyway....

Fired up the A/C for the first time the other day only to receive warm air. A/C light is on steady with no flashing. Clutch isn't engaging on the compressor. Is there a low-pressure switch that won't allow it to engage if there's no refrigerant? Which of course I can't check because the compressor won't turn on. What are the proper steps for troubleshooting this? Any help is much appreciated!

 

[drmorbius]

Lesson learned...even if it's a cold day outside when you're test driving a vehicle...make sure the A/C works!! Anyway....

Fired up the A/C for the first time the other day only to receive warm air. A/C light is on steady with no flashing. Clutch isn't engaging on the compressor. Is there a low-pressure switch that won't allow it to engage if there's no refrigerant? Which of course I can't check because the compressor won't turn on. What are the proper steps for troubleshooting this? Any help is much appreciated!

Check the 10 amp gauge fuse and the heater relay.

 

[arracado]

Both check out. Check for coolant next I guess, if none, look for leaks and recharge. Hopefully that's what it is and not a bad compressor.

 

[drmorbius]

Both check out. Check for coolant next I guess, if none, look for leaks and recharge. Hopefully that's what it is and not a bad compressor.

The system has a dual pressure switch for protection so I guess adding refrigerant would be the next step.

 

[fourwd1]

Connect 12V directly to the connector on the compressor. That will tell you if the comp and clutch work.

 

[arracado]

Thanks for the help guys. When I said "coolant" I meant refrigerant, but you probably already knew that

 

[arracado]

OK, so my friend and I recharged the system and it popped right on, nice cold A/C as you'd expect. That was a few weeks ago. Today it warmed up and I turned it on and once again got hot air. Clearly there's a leak somewhere...any input on how to troubleshoot this? I read that there are dyes you can put into the system to find the leak...do they work? Or should I just take it to a shop? Thanks in advance.

 

[Justin727]

OK, so my friend and I recharged the system and it popped right on, nice cold A/C as you'd expect. That was a few weeks ago. Today it warmed up and I turned it on and once again got hot air. Clearly there's a leak somewhere...any input on how to troubleshoot this? I read that there are dyes you can put into the system to find the leak...do they work? Or should I just take it to a shop? Thanks in advance.

leak detection kit. Comes with dye, light, and glasses.

Maybe easier for you to take it to a shop!

 

[arracado]

Yeah I'm thinking a shop might be the way to go. How often will I need an A/C leak detection kit, you know? Should just save the money and put it toward the repair.

Do leaks tend to be expensive repairs? I'm guessing it depends where the leak is...

 

[arracado]

Figured I'd first try the Toyota dealership I bought it from. No warranty but it's worth a shot to see if they'll check it out for me.

 

[Justin727]

Yeah I'm thinking a shop might be the way to go. How often will I need an A/C leak detection kit, you know? Should just save the money and put it toward the repair.

Do leaks tend to be expensive repairs? I'm guessing it depends where the leak is...

Just depends where it is in the system..
Sometimes it's just an Oring which is a cheap fix.
Other times it could be a hose, condensor, evaporator, etc which can get expensive.
Hopefully its just an oring or hose for ya. Could even possibly be a leaky valve core which is also a cheap fix.


You'll only need it once in this paticular case. But if you loose air agian in the future on this car or another its always handy to have with you. I have a shitload of a/c tools I've barely used but in the end it pays for itself.

 

[arracado]

Since we only used one can of refrigerant when we recharged it, I'm thinking that maybe I just didn't get enough in there. Gonna pressure test it and add another can if it needs it. The compressor does engage so there's enough in there for that.

 

[arracado]

Guys what is the eye in the evaporator supposed to look like when the system is charged? We added another can and I put some dye in there to find the leak. It's still blowing cold after a couple of days, and I can't see any leak yet under a blacklight. The eye in the evaporator looks as if there is milky white liquid passing through it quickly...is that what it's supposed to look like when charged?

 

[arracado]

Well after a summer of having this "fixed" only to have it start blowing warm after a while, the shop says it should be good to go. They replaced the condenser, all the o-rings, and finally found the final leak on the evaporator in the cabin. They've charged and evac'd it a number of times, but he says he can only get it down to 50° output. Is that acceptable? I'm going to pick it up shortly.

 

[bills86e]

NO, You will NOT BE HAPPY if it is not in spec. Warm air sucks. Barely cool is worse!
Replace the compressor & dryer, flush all components separatly and new oil & refridgerant
to exact quantity spec. Then Nitrogen finish. Yeah, a few more bucks but worth it!

 

[blueblur1984]

If you need to replace the compressor you can save some serious money by doing it yourself. A few things I learned on mine:

Get the system evacuated before starting

Remove the two bolts (10mm?) that hold the hoses in place. Wiggle them loose as they are held in tight by a couple of o rings.

Four bolts hold it in place and after moving some hoses you can slip the compressor out the bottom

Remove the fitting from the old ac compressor and put it on the new one. You may as well replace the o rings since its out anyway.

When you slip the new one in it helps to have a second person guide it from the top. Be absolutely sure to put the lower two bolts in the new compressor BEFORE trying to get it back in the truck! There is not enough clearance to do it after the fact...I learned that one the hard way

 

[audiness]

What type of refrigerant oil did you guys use? I saw on my OEM denso compressor it said ND type oil, but can't seem to find that at the auto store. Is regular old refrigerant oil good enough?

 

[zacattack20]

Pag-46 is the equivalent oil.

 

[ckells95]

I'm having a similar problem except the compressor will just click on and off, resulting in hot air.. No good! I unplugged the switch on the high-pressure line, took a paper clip and bent it to where the ends could be inserted into the plug to "jump" the circuit, which kept the compressor turned on. I'm still trying to figure it out, but what that did was confirm that there is either a blockage somewhere in the system or the switch is bad, I suggest doing the same thing and see what happens.

 

[tman100z]

I'm having a similar problem except the compressor will just click on and off, resulting in hot air.. No good! I unplugged the switch on the high-pressure line, took a paper clip and bent it to where the ends could be inserted into the plug to "jump" the circuit, which kept the compressor turned on. I'm still trying to figure it out, but what that did was confirm that there is either a blockage somewhere in the system or the switch is bad, I suggest doing the same thing and see what hap

did you fond anything out, mine just started doing the same thing????