A/C problems!!

88GT460 · Jun 13, 2005

Ok, I have searched on this site for related problems and I am 90% sure that the pressure switch is the bad part as when I cross the two contacts on the wire that connects to the computer or whatever it stays on constantly. But if I connect it back to the sensor it does blow cold air but the compressor kicks off in a few minutes and might come back on at a later time (I do not drive very far everyday) Since it is much cheaper to replace the sensor to see if thats the problem I need to know where to get one at..

The local autozone is not in the favor of being smart. so i think I have found one on 50Resto.com

http://secure.50resto.com/product1.cfm?SID=1&Product_ID=225&Category_ID=586

Please tell me if this is the right thing, if not.. please point me in the right direction.

edit: this is for a 94 Mustang GT hardtop

1fst5.0 · Jun 13, 2005

I just had the same problem. It turned out to be my pressure switch. I picked one up at Advance Auto parts for about $20, now its nice and cool

mo_dingo · Jun 13, 2005

no, that is the ECT, engine coolant temperature sensor. It reads the temp of the antifreeze/water mixture.

The pressure sensr is mounted to the canister on the firewall. If you remove the connector, and use a jumper wire, and connect the two terminals, the compressor should kick on (engine running, a/c switch on a/c).

First thing to see is if you have ENOUGH refridgerant. Get a r-134a fill kit with pressure gauge at autozone. Check to see if you have enough pressure at the low side of the system (passenger side, need to loosen the STB to get access).

If you have enough refridgerant, then your pressure sensor is bad.

autozone doesn't stock the part. You need to get it at another store, maybe pep boys or checker. Try an a/c shop, they may stock it.
Scott

88GT460 · Jun 13, 2005

mo_dingo said:
no, that is the ECT, engine coolant temperature sensor. It reads the temp of the antifreeze/water mixture.

The pressure sensr is mounted to the canister on the firewall. If you remove the connector, and use a jumper wire, and connect the two terminals, the compressor should kick on (engine running, a/c switch on a/c).

First thing to see is if you have ENOUGH refridgerant. Get a r-134a fill kit with pressure gauge at autozone. Check to see if you have enough pressure at the low side of the system (passenger side, need to loosen the STB to get access).

If you have enough refridgerant, then your pressure sensor is bad.

autozone doesn't stock the part. You need to get it at another store, maybe pep boys or checker. Try an a/c shop, they may stock it.
Scott

Well, I know where it is located and I know that it is full of r-134a since I just filled put 34oz in it. Was completely blowing hot air before. anyway I will try another parts store here..

Another quick question for the dumb. Do you have to decharge it to change that sensor ?? It looks like when I pull it out all the pressure would release .. ?? Not sure, but I thought I would ask before I unscrew the sensor.

88GT460 · Jun 14, 2005

anyone ? plz

mo_dingo · Jun 14, 2005

88GT460 said:
Well, I know where it is located and I know that it is full of r-134a since I just filled put 34oz in it. Was completely blowing hot air before. anyway I will try another parts store here..

Another quick question for the dumb. Do you have to decharge it to change that sensor ?? It looks like when I pull it out all the pressure would release .. ?? Not sure, but I thought I would ask before I unscrew the sensor.

If you had to add any refridgerant, you have a leak, which means you are probably not full on efridgerant, which means the pressure sensor is doing it's job by not letting the compressor come on.

Check the pressure on the low side and see if you are low. If you are, fix the leak, then it should work just fine.

Pressure sensor is not actually make contact w/ the refridgerant. You can remove it w/o discharging the system. Good question, don't feel dumb.
Scott

BlownFiveLiter · Jun 14, 2005

I had the same problem, which was the low pressure sensor being the culprit. Mine actually allowed my compressor to run with zero refrigerant in my system, causing it to get so hot, it literally caught fire. About $250 or so later in parts, my A/C works again, but had I known the sensor was bad, I would've just gotten a new one sooner. It was $22 I believe at NAPA. Mo dingo is correct that the sensor doens't make contact with the refrigerant, too. It's on a schraeder valve on top of the accumulator, so it's just a quick 2 minute fix.

94-302-vert · Jun 15, 2005

Just and FYI. the pressure switches do make contact with the refrigerant. Oterhwise how would they sense the pressure of the refrigerant.

Now whether or not you will leak refrigerant is determined mainly by the type of fittign and whether or not there is a deflator installed in the system port. Based on what everyone is saying it sounds like there is a deflator in the port the prevents the system from evacuating when you pull off the switch.

Chris

Venom351R · Jun 15, 2005

AC....whats that

I turned mine on for the first time this yr this past weekend just to run it for a few mins but it blew nothing but warm air. Guess it needs a recharge. Good thing I dont live in a state where AC is a must b/c I dont turn it on very often anyway and even when I do the windows are still down.

A/C problems!!

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