This problem is really annoying. Just wondering what would tell the AC not to cycle on? Although on a normal hot day driving with AC on I experience no issues, yet when humid AND NEEED TO DEFOG WITHOUT MELTING THE CAR!! Won't turn on unless I leave the car off for 30+mins. What sensor could be bad and telling the AC not to turn on? What does that sensor behind the glove box do going into the heatercore btw?

So if you turn on the AC all is fine

 

In the defrost mode, the AC compressor does not come on?

 

When this happens, if you turn on the AC does the compressor start to work?

 

If so, I'd say you had a bad control panel.

Year/model?

 

When its humid and you turn on the defroster, what happens? Does the system move air at all?

 

What happens when you change the temp setting?

 

Does the compressor engage?

Its a 1994 Legacy Turbo sedan. Whethers its on A/C, max a/c, DEF or Heat DEF. Same thing Cold or hot or in the middle. Compressor just doesn't want to engage. I have also tried replacing the main HVAC controller btw.

Sounds like it could be the compressor going.

 

Try jumping the pressure switch at the dryer, also check for bubbles

Try jumping the compressor relay in the engine compartment fuse/relay box.

 

If it kicks in with the pressure switch, you need to service the system

As with most things AC, 1st step is to get real AC gauges on the system. this will tell you everything you need to know (like low coolant, too high, bad compressor etc etc etc).

 

 

I dont know why everyone wants to skip this first step.

 

 

nipper

Strange, isn't it, Nipper? Get that all the time in the shop, too.

Strange, isn't it, Nipper? Get that all the time in the shop, too.

 

 

Notice how no one has suggested a slipping belt either?

 

 

rain makes a great lubricant.

 

People need to start off with the cheap fixes first, they always seem to go for the most $$$

 

lol today again works at the beginning steady, but as soon as 3 or so hot restarts with a few minute rests the AC won't work seems like it has to do with engine bay heat. My dad has to get adapters so he can hookup his gauges (hes i HVAC hehe) anyway ill tell you guys whats up, jumping the pressure switch sounds like a good test.

If I'm not mistaken, the 90-94 Legacys used a Zexel brand compressor. Same as some of the 2000 and up Subarus.

 

If you do have a Zexel compressor, read this thread:

 

http://www.ultimatesubaru.org/forum/showthread.php?t=102171&page=2

Probably just the 94 models used the zexel compressor. I don't recall it being zexel though to be honest. Only 94's had 134a refrigerant. Thanks though will definitely look into this!

If you need a compressor, let me know I have several used ones.

If you need a compressor, let me know I have several used ones.

 

well i have a r12 one from my 93 which appears to have the same connections. Thanks though!