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2001 eldorado,2008 DTS,2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
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Discussion Starter #1 (Edited)
After fixing the fast idle issue, I proceeded to the lack of air conditioning. After measuring low side pressure (65#) and clearing BCM codes, the compressor clutch won't engage. Disconnect the battery; no engagement. WTF. I've always been able to clear body codes to get the compressor to kick In long enough to get some Freon in and keep things rolling. Not this time.
What can I do next? Can I jumper one of the pressure/temp sensors?
Temp set at 60°, but the HVAC kicks it out to ECON after a few minutes.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
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19,270 Posts
Re: A/C compressor won't engauge-'89 eldo

After fixing the fast idle issue, I proceeded to the lack of air conditioning. After measuring low side pressure (65#) and clearing BCM codes, the compressor clutch won't engage. Disconnect the battery; no engagement. WTF. I've always been able to clear body codes to get the compressor to kick In long enough to get some Freon in and keep things rolling. Not this time.
What can I do next? Can I jumper one of the pressure/temp sensors?
Temp set at 60°, but the HVAC kicks it out to ECON after a few minutes.
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low side pressure (65#)
that is obviously static pressure -
and yes - the pressure is too low to operate the compressor -

and clearing BCM codes, the compressor clutch won't engage.
what codes?

low pressure is one thing -
a failed pressure switch is another -

try this -

engine off -

have the AC gauges connected -

have the full can of freon connected -

valve on the freon can open -

low-side service valve on the gauges open -

turn ignition on -

turn AC on -

set AC temp to 60* -

clear the codes -

start the engine -

the compressor should engage and draw the can of freon in -

when the can of freon is empty -

close the low-side service port -
the compressor will probably start cycling -
add more freon until the proper pressures are reached -

--------------

sometimes -
the low pressure switch is so sensitive
that it just won't allow the compressor to engage -

if this happens - you can unplug the switch -
and put a jumper across the plug to force it -

but - be very mindful of the low pressure -
 

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Registered
2001 eldorado,2008 DTS,2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
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1,716 Posts
Discussion Starter #3
Turns out, my gage set let me down. I jumpered the low press switch and the compressor came on, but the gage said 60#, didn't move. Jug of 12 Is hooked up but the valve on the gage set was closed. Removing the fitting from the accumulator, I noticed the center pin In the low side hose that Is supposed to press In on the pin In the accumulator Schreater (?)valve, was missing! Apparently the 60# I was reading was from the drum pressure that must of been present at hookup.
Swapping gage sets, I now read 5# Freon. Injecting some Freon, the compressor starts pumping, but it just doesn't sound right. I know that sound; it's a failing compressor. Time for a new one; this one's original.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
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19,270 Posts
Turns out, my gage set let me down. I jumpered the low press switch and the compressor came on, but the gage said 60#, didn't move. Jug of 12 Is hooked up but the valve on the gage set was closed. Removing the fitting from the accumulator, I noticed the center pin In the low side hose that Is supposed to press In on the pin In the accumulator Schreater (?)valve, was missing! Apparently the 60# I was reading was from the drum pressure that must of been present at hookup.
Swapping gage sets, I now read 5# Freon. Injecting some Freon, the compressor starts pumping, but it just doesn't sound right. I know that sound; it's a failing compressor. Time for a new one; this one's original.
===============================
Removing the fitting from the accumulator,
I noticed the center pin In the low side hose
that Is supposed to press In on the pin In the accumulator Schreater
(?)valve, was missing!


that ALWAYS happened when removing the service hose - :rant2:

NAPA sells/sold a plastic bag
with 5 brass core depressors and 5 rubber inserts
for a few bucks -
 
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