RUTI'S WS6 TA

Hi. Need a little help here. Will the A/C engage if it is out of freon? I don't hear the A/C clutch engaging while at max cool and the fan on high. The A/C worked earlier this year. Is it possibly the A/C switch?

Thanks for any advise on what to look/check for.

Paul

LS6427

iTrader: (2)

If the pressure switch is working properly...no, the compressor will not come on when low on 134/freon.

.

fleetmgr

You'll have to add freon to get it to engage if its completely empty, so in that regard it's working the way it's supposed to.

Now, you'll have to add freon to find the leak.

RUTI'S WS6 TA

I bought one of those 134A kits that came with a gage. The needle goes in to the RED which is supposed to indicate a possible mechanical problem. Does that help point this issue in any particular direction as to what I can check next? Thanks

fleetmgr

Does the gauge actually indicate a psi reading, or does it just have the color indication? If it gives an actual pressure reading, what is it?

RUTI'S WS6 TA

Let me check that tonight & I'll post that later. Thanks

jimmyblue

iTrader: (11)

I'm chasing a no-compressor-engage problem right
now, system has pressure but no clutch signal. The
A/C clutch takes a pretty involved path from PCM
to climate control to relay to clutch. Have to chase
all the way back and see where it's quitting.

Helm books' first troubleshooting block is, check for
codes. Since the PCM is meddling by design, it may
have decided not to play for some obscure reason.

oifish

iTrader: (1)

I had the same problem recently on my A/C. I took it to a shop for them to troubleshoot. They fixed it by "resetting the codes" and then the A/C would kick on, and I could fill it then. Im pretty sure they disconnected the battery to clear any codes.

So disconnect your battery for 15 min. or so and see if that works.

dragonrage

Guys, please don't call it Freon, because it's not. R134a it is.

However, I recommend HC-12a (the 'a' there is VERY important) - can be used in place of R12 and R134a both. It does have hydrocarbons which are flammable but it's actually less dangerous than R134a is. See http://en.wikipedia.org/wiki/HC-12a

Of course, the first thing to do is fix the leak. If you're low on refrigerant, there IS a leak. Change the oil while you're at it. Very important. The stuff sucks up water worse than brake fluid and it's a very bad thing. Change the oil and if you want, you can put refrigerant in with UV dye and wait 'til it leaks out again and try and find the leak with a black light.

Condensers are common candidates due to road debris.

slow

iTrader: (7)

Jimmyblue, can you turn the compressor clutch on with hptuners or another tuning software?

I have seen the disconnect the battery take care of this issue when a compressor clutch won't engauge either due to no refrigerant, and then adding some, or when you happen to have the pressure sensor disconnected at startup.

Ryan

RUTI'S WS6 TA

It's close to 100 psi. The car has not given me an SES light. If the high psi number says something, please let me know what that means or could mean. I can try disconnecting the battery tomorrow to see if that does anything. Thanks for all the input.

RUTI'S WS6 TA

If at 100 psi, what could that mean?

fleetmgr

Without the compressor running, it means that it was about an 86 degree day when you looked.

It also means that there should be enough there to get the compressor to run.

RUTI'S WS6 TA

If there is enough 134-A in the system, what could be the reason why the A/C is not working properly?

fleetmgr

Have you already checked all the things already mentioned?

jimmyblue

iTrader: (11)

I looked at mine some today. I similarly have ~ 100
PSI system charge. The high side path is all OK and
jumpering the A/C Comp relay makes the clutch pull
in. It is the relay coil low side which is not right. Have
to go see what that's coming from. My mechanic
buddy says he's seen a lot of pressure switches fail,
that's one possibility.

I read & cleared codes to no effect. I have some
presistent C and U codes (brakes, restraints, Class
2 comms) which won't go away but none of it looks
like it ought to bother the A/C, and the pull-fuses
reset helped none.

I'll keep you posted on what I find chasing down the
A/C Comp relay coil low side path.

RUTI'S WS6 TA

I tried the battery disconnect for 15+ minutes - no go. Can someone point where the pressure switch would be located on the LS1? Again thanks for all the input. I don't have a tuner so I can't tell if it's throwing any codes out. I'm a real novice when it comes to A/C stuff. So Fleetmgr and Jimmyblue, I'm following your lead.

jimmyblue

iTrader: (11)

I have narrowed mine down to something between
the A/C pressure sender and the PCM.

I can force the A/C compressor to engage by the
bidirectional controls (HPTuners) and can see that
the clutch status follows, but there is an A/C pressure
"holdoff" bit that's red, and apparently inhibiting the
normal operation. A/C blows cold when forced.

A/C pressure sensor voltage is stuck at 3.71 at
rest, and does not move w/ the compressor pumping.
So this voltage is whack, and it looks like this is the
"cutout switch" (logically done within the PCM based
on sensor voltage too high or too low) on my vehicle.

So next step is to put the meter to it, see if the value
matches (so bad sender) or doesn't (bad connection?).

jimmyblue

iTrader: (11)

Finally ran this down to an "Oops!" on my part; when
I did the IAT relocation the other week I cut the low
reference as well as the signal, close by the PCM and
swapped them to the new wiring. But the IAT GND is
also the A/C pressure GND so that ended up floating
and messed up the sensor output. I made it a "T"
joint and it's all working now.

fleetmgr

The HP and LP switches are in the back side of the compressor. If you look there, you'll see a pair of wire connectors, one on each switch. You'll have to look in a book to see which is which. The switches are held in by snap rings, and have an oring around them to seal. About $25 ea. at NAPA.