A/C blows warm and hot air only
07-06-2007, 02:07 PM
#21
TECH Senior Member
Yeah, with the compressor off you're just reading the static pressure. My helms says above 75* PSI will be around 70, above 90* PSI will be 100 PSI. The static pressure test is the first step in determining if there's enough in the system to safely to operate it for the performance test.
07-06-2007, 02:46 PM
#22
12 Second Club
Thread Starter
iTrader: (1)
Join Date: Jul 2005
Location: Grand Rapids, MI
Posts: 497
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Jon5212
You have no need to jumper the switch, you said the compressor is cycling, which means it is low on refrigerant, you have to read the pressure when the compressor is running, when it is not running 90-100 PSI on the low side is correct. it should drop considerably once the compressor kicks back on, add refrigerant.
07-06-2007, 02:53 PM
#23
TECH Fanatic
iTrader: (2)
Join Date: Jan 2006
Location: Indianapolis Indiana
Posts: 1,299
Likes: 0
Received 0 Likes
on
0 Posts
You can look at the front of the compressor, when its off just the pulley is spinning and the center is stationary, when it clicks on the center will start spinning too
07-06-2007, 03:11 PM
#24
12 Second Club
Thread Starter
iTrader: (1)
Join Date: Jul 2005
Location: Grand Rapids, MI
Posts: 497
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Jon5212
You can look at the front of the compressor, when its off just the pulley is spinning and the center is stationary, when it clicks on the center will start spinning too
07-06-2007, 05:03 PM
#26
TECH Senior Member
Don't think there's a separate low and high pressure switch - just a "refrigerant pressure sensor."? Follow the two alum AC lines back towards the firewall on the passenger side, it's on the lower line on mine and has an electrical connector from the harness going to it - can't miss it.
07-06-2007, 05:12 PM
#27
TECH Senior Member
Here's what it looks like on a LT1 car, ours is in the same spot. http://shbox.com/1/refrigerant_sensor.jpg
07-06-2007, 05:24 PM
#28
12 Second Club
Thread Starter
iTrader: (1)
Join Date: Jul 2005
Location: Grand Rapids, MI
Posts: 497
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 2001NBMZ28
Here's what it looks like on a LT1 car, ours is in the same spot. http://shbox.com/1/refrigerant_sensor.jpg
07-06-2007, 07:22 PM
#29
TECH Enthusiast
Join Date: Jan 2007
Location: Sugar Land, Tx
Posts: 578
Likes: 0
Received 0 Likes
on
0 Posts
When your A/C wasn't getting cold was there a green liquid leaking under the front of the car? Because also just starting today i am having the same problem and im not sure if thats antifreeze or just A/C fluid? Please help. Thanks
07-06-2007, 07:25 PM
#30
12 Second Club
Thread Starter
iTrader: (1)
Join Date: Jul 2005
Location: Grand Rapids, MI
Posts: 497
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by crapyboy750
When your A/C wasn't getting cold was there a green liquid leaking under the front of the car? Because also just starting today i am having the same problem and im not sure if thats antifreeze or just A/C fluid? Please help. Thanks
07-06-2007, 07:44 PM
#31
12 Second Club
Thread Starter
iTrader: (1)
Join Date: Jul 2005
Location: Grand Rapids, MI
Posts: 497
Likes: 0
Received 0 Likes
on
0 Posts
I just checked the compressor again and it is running when I turn the A/C on. I will try adding some refrigerant again. However, I do believe the compressor was running earlier when the gauge read 90 PSI. Should I still try to add refrigerant? When will the PSI drop? Thanks.
07-06-2007, 09:41 PM
#32
12 Second Club
Join Date: Feb 2005
Location: baytown, tx
Posts: 147
Likes: 0
Received 0 Likes
on
0 Posts
your a/c keeps switching on and off becuase of the low press. switch, the r134 can will only plug into the low side, run car on max a/c, plug can and tilt can, spray can for 15 to 20 seconds and release, the pressure on the gauge should drop as the systems temp drops, the a/c will continue running and the can should start to get cold, continue till the gauge hit's the blue are which means "full", my tahoe had a leak and every time i'd refill my starting pressure would be high
07-07-2007, 06:14 AM
#33
12 Second Club
Thread Starter
iTrader: (1)
Join Date: Jul 2005
Location: Grand Rapids, MI
Posts: 497
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by calz28
your a/c keeps switching on and off becuase of the low press. switch, the r134 can will only plug into the low side, run car on max a/c, plug can and tilt can, spray can for 15 to 20 seconds and release, the pressure on the gauge should drop as the systems temp drops, the a/c will continue running and the can should start to get cold, continue till the gauge hit's the blue are which means "full", my tahoe had a leak and every time i'd refill my starting pressure would be high
07-07-2007, 07:42 AM
#34
TECH Senior Member
iTrader: (23)
Join Date: Aug 2005
Location: Watertown, NY
Posts: 8,797
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Jon5212
You can look at the front of the compressor, when its off just the pulley is spinning and the center is stationary, when it clicks on the center will start spinning too
07-08-2007, 10:16 AM
#36
TECH Fanatic
iTrader: (2)
Join Date: Jan 2006
Location: Indianapolis Indiana
Posts: 1,299
Likes: 0
Received 0 Likes
on
0 Posts
I guess the biggest thing is making sure you don't have leaks, because 90% of the time it runs low on refrigerant because of a leak. The compressor should run continuously when at idle when you have the correct charge on it. The only reason for it to cycle on and off is low pressure in the system. And the reason you can fill the low side with liquid (the can upside down) is because our systems have an orifice tube which won't allow a TON of refrigerant to jam into the system all at once so it is safe on the compressor.
07-08-2007, 12:02 PM
#37
12 Second Club
Thread Starter
iTrader: (1)
Join Date: Jul 2005
Location: Grand Rapids, MI
Posts: 497
Likes: 0
Received 0 Likes
on
0 Posts
Well I emptied a large can of r134a into the low pressure side and it still blows hot air. The pressure is at 45 PSI which is should be about right for a 90* day. I checked the pressure again after driving it for awhile and it was still about the same. It may have dropped a little (around 5 PSI). Shouldn't the air have gotten colder for a little bit even if there is a leak? What else should I check? The compressor seems to be running fine. Thanks.
07-09-2007, 12:33 AM
#39
Originally Posted by ARCTICWHITE98Z28
Well I emptied a large can of r134a into the low pressure side and it still blows hot air. The pressure is at 45 PSI which is should be about right for a 90* day. I checked the pressure again after driving it for awhile and it was still about the same. It may have dropped a little (around 5 PSI). Shouldn't the air have gotten colder for a little bit even if there is a leak? What else should I check? The compressor seems to be running fine. Thanks.
07-09-2007, 06:28 AM
#40
TECH Fanatic
iTrader: (2)
Join Date: Jan 2006
Location: Indianapolis Indiana
Posts: 1,299
Likes: 0
Received 0 Likes
on
0 Posts
I think you need to do a total evacuation of the system with a vacuum pump, then get get some leak detector or take it to a shop and have them run a leak detection on it. Seems like you have a leak. With the A/C running have felt either of the pipes that go into the firewall or to the compressor? One should be pretty ice cold. If its not, it is more than likely still low on refrigerant, but if it IS cold you may have a problem with your HVAC system and it may not be closing off a vent correctly or it is stuck on the "hot setting" opening the damper to let air come across the heater core. I think your best bet would just take it to an A/C professional and have them run a leak check.