WTH is wrong with my A/C!?
Thread Starter
Teching In
Joined: Jan 2007
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WTH is wrong with my A/C!? I swear I've tried almost everything, and its getting way to hot to be driving without it.
Basically When I turn the switches to a/c max or wherever, I'm not getting any cold air. High side seems normal enough, but the Low side is peaking towards 95 psi. Seems a bit high to me. So I've recovered, vac'd the system, and recharged TWICE! And pressures are still sitting around the same level.
The compressor will not turn on with any switches, However I jumped the compressor relay and got it to turn on, Immediately a/c got very cold and everything seemed like it was working fine.
I also checked the pressure switch, has 5v to the connector, and 1.4v coming from the pressure sensor with the compressor turned off. I Jumped the relay again and with the compressor on it was reading 2.4v. This is another I wasn't so sure about, I'm not sure if those voltages are within spec. any help would be appreciated.
One thing I havent had a chance to do was pay attention to the actual lines. In a bit ill go at jump the relay again and watch the lines temps.
anybody?
p.s. sorry for the long read, but you might learn somethin.
Basically When I turn the switches to a/c max or wherever, I'm not getting any cold air. High side seems normal enough, but the Low side is peaking towards 95 psi. Seems a bit high to me. So I've recovered, vac'd the system, and recharged TWICE! And pressures are still sitting around the same level.
The compressor will not turn on with any switches, However I jumped the compressor relay and got it to turn on, Immediately a/c got very cold and everything seemed like it was working fine.
I also checked the pressure switch, has 5v to the connector, and 1.4v coming from the pressure sensor with the compressor turned off. I Jumped the relay again and with the compressor on it was reading 2.4v. This is another I wasn't so sure about, I'm not sure if those voltages are within spec. any help would be appreciated.
One thing I havent had a chance to do was pay attention to the actual lines. In a bit ill go at jump the relay again and watch the lines temps.
anybody?
p.s. sorry for the long read, but you might learn somethin.
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Joined: Mar 2010
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The prssure switch is not a switch...its a transducer. That means it outputs a voltage according to the pressure in the system.
The pcm uses this voltage reading to determine if its gonna turn the compressor on.
The tranducer could be bad(common) or the charge is too much or too little or something is blocked like the inlet screen on the orifice tube.
OR MAYBE YOU JUST DON"T DESERVE AIR COND!
Good Luck Obiwan
Oh yeah i fergot to tell you be sure to check you 're requesting AC (telling the pcm you want the ac on) The HVAC control has a output for this, be sure its working.
The pcm uses this voltage reading to determine if its gonna turn the compressor on.
The tranducer could be bad(common) or the charge is too much or too little or something is blocked like the inlet screen on the orifice tube.
OR MAYBE YOU JUST DON"T DESERVE AIR COND!
Good Luck Obiwan
Oh yeah i fergot to tell you be sure to check you 're requesting AC (telling the pcm you want the ac on) The HVAC control has a output for this, be sure its working.
Last edited by HotSilverBird; Jun 13, 2010 at 04:09 PM.
Have you checked to see if the low pressure switch is bad? If it is it will give a false reading of no freon and will not let the compressor kick on. Ive also seen a bad pcm causing no signal to be sent to the compressor
Thread Starter
Teching In
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Thanks for the replies guys, I just found all the pin outs for the pcm ac controls. I left my voltmeter at work yesterday so Ill have to wait to check the pcm outputs.
As far as the pressure switch ( I knew it was not technically a switch) It is still putting out varying voltages which makes me want to lean towards its in working order. I vac'd the system for 15 min. and the fact that the A/C blows cold when compressor is on is making me think its not the orifice tube.
I havent looked into the HVAC control, but the engine rpm spikes when I turn it on the a/c mode again making me believe its working, but I will test and get back.
As far as the pressure switch ( I knew it was not technically a switch) It is still putting out varying voltages which makes me want to lean towards its in working order. I vac'd the system for 15 min. and the fact that the A/C blows cold when compressor is on is making me think its not the orifice tube.
I havent looked into the HVAC control, but the engine rpm spikes when I turn it on the a/c mode again making me believe its working, but I will test and get back.
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can you force the AC compressor on with a tech2 or tuning software? also, try to disconnect the battery, I have seen this necessary after disconnecting the AC pressure sensor and then reconnect to resolve the issue.
Ryan
Ryan
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Teching In
Joined: Jan 2007
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I will try disconnecting the batt. and let you know. Unfortunately I do not personally have any access to tech2 or hptuners.
Thread Starter
Teching In
Joined: Jan 2007
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The fans will only turn on with the compressor though correct? The fact that it is in A/C mode doesn't mean the fans will automatically come on?
With the car running and the a/c switched on, trying tapping on the low pressure switch with a wrench or something and see if it will kick on. My truck's A/C was working great and all of a sudden stopped so I pulled over and tapped on the switch and it kicked right on. Replaced it for like $25 and I was back in business.
