AC won't run after driving car for a while when raining??

ericem · Post by **ericem** » Sun Sep 27, 2009 5:48 am

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?

BSOD2600 · Post by **BSOD2600** » Sun Sep 27, 2009 8:50 am

I believe that goes into the ac evaporator box and gives the AC system a temp reading.

ericem · Post by **ericem** » Sun Sep 27, 2009 9:14 am

I should possibly replace it I guess. I took it out once and it was all rusty the cage itself. Ill probably remove it soon and blow it out.

Post by **Legacy777** » Sun Sep 27, 2009 10:30 pm

Without knowing info on the system pressures, it's kind of a guessing game.

The fact you have to let the car sit for 30 min would seem to indicate that it's a mechanical/system issue vs. an electrical issue.

ericem · Post by **ericem** » Mon Sep 28, 2009 3:11 am

Heres the deal always does it when the car is in the city driving making short trips, but if i drive steadily no issues. Did it today as well. my dad thinks it might have something to do with the fact that my fans are not cycling and something is to hot causing the high pressure to kick on the AC. What connector is for the high pressure on the AC? My dad needs to get ahold of a adapter so he can hookup his gauges btw.

Post by **Legacy777** » Mon Sep 28, 2009 7:10 pm

You're probably right. I notice with mine since installing the exchanger for my AWIC setup that the fans will kick on high speed via the AC pressure switch.

As for your dad hooking up his gauges, the ports are right there at the compressor.

ericem · Post by **ericem** » Tue Sep 29, 2009 5:31 pm

Legacy777 wrote:You're probably right. I notice with mine since installing the exchanger for my AWIC setup that the fans will kick on high speed via the AC pressure switch.

As for your dad hooking up his gauges, the ports are right there at the compressor.

ya I know, but the problem is r134A system has diffferent connections then the r12 systems did. My dad guages use the same connections as the r12 system.

Post by **Legacy777** » Tue Oct 06, 2009 4:27 pm

I know you can buy adapters going from R12 to R134a, but don't know if you can buy ones going the other way around.

He could probably buy the 134a fittings that screw on to the hoses.

ericem · Post by **ericem** » Tue Oct 06, 2009 6:32 pm

he said at his supplier he can get them just keeps forgetting to get them!

Buffman · Post by **Buffman** » Tue Oct 06, 2009 7:19 pm

Are there relays for the AC in the glove box area? It seems on defrost, and low fan speed AC and MAX AC, it likes to cycle on and off (or is it supposed to?) I hear what sounds like a relay clicking when it happens in the glove box area. I thought all AC relays were underhood? Pressures are good. AC condensor, and Accumulator new.

Post by **Legacy777** » Wed Oct 07, 2009 5:51 pm

Yes, the A/C cut relay is mounted on the evap box.

http://www.surrealmirage.com/subaru/fil ... tion03.jpg

roundeye · Post by **roundeye** » Wed Oct 07, 2009 5:59 pm

a/c cut relay is to disengage compressor on wot. sounds like you have a bad evaporator temp sensor. the part in the metal cage is the blower motor resistor. temp sensor connector is on top of the box, sensor is clipped to evaporator fins. easy to bypass to test.

ericem · Post by **ericem** » Wed Oct 07, 2009 7:01 pm

i can access it by just removing the glove box I don't remember now....

roundeye · Post by **roundeye** » Thu Oct 08, 2009 5:52 am

you can access the connector for the temp sensor easily, but to remove it, the whole evaporator box has to come out. not too bad to do, but you will need to evacuate the a/c first, and recharge after. great chance to clean out the years of crap that build up in there also.

Buffman · Post by **Buffman** » Thu Oct 08, 2009 3:36 pm

Josh is there a part # for that AC cut relay? What's procedure to test/bypass the temp sender? It never seems to do it when AC is on MAX and full fan speed, or AC full fan speed, but low speeds or any speed defrost it likes to cycle. Sometimes it will act just normal. AC system as I mentioned has new ACC and Condensor. Was converted to 134a to 80% of r12 charge. all oil was drained out and filled with ester oil. I think its something electrical as I mentioned sometimes it's fine.

Post by **Legacy777** » Thu Oct 08, 2009 6:30 pm

Your pressures are probably getting too high and that is what is causing it to cycle. When the fan is on full blast that will help drop the discharge pressures.

Before you go messing too much with electrical, I'd suggest seeing what the system pressures are when the compressor kicks on and off. That will tell you a lot!

ericem · Post by **ericem** » Thu Oct 08, 2009 6:37 pm

roundeye wrote:you can access the connector for the temp sensor easily, but to remove it, the whole evaporator box has to come out. not too bad to do, but you will need to evacuate the a/c first, and recharge after. great chance to clean out the years of crap that build up in there also.

Ya i always wondered about all the garbage that goes in. Does the dash have to come out just curious.

Post by **Legacy777** » Thu Oct 08, 2009 6:45 pm

No, the dash doesn't have to come out. Once you remove the lines from the evap box, there's two bolts you remove and the evap box comes right out. I was surprised at how easy it was.

Buffman · Post by **Buffman** » Thu Oct 08, 2009 10:46 pm

Legacy777 wrote:Your pressures are probably getting too high and that is what is causing it to cycle. When the fan is on full blast that will help drop the discharge pressures.

Before you go messing too much with electrical, I'd suggest seeing what the system pressures are when the compressor kicks on and off. That will tell you a lot!

okay will do.

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AC won't run after driving car for a while when raining??

AC won't run after driving car for a while when raining??