Another AC Thread

ok, need a little help here. when i turn on my ac switch on the dash, nothing happens, no change in rpm, no click. just blows warm air.

i checked the glass tube fuses with multimeter, all good. i jumped the compressor, clutch kicks, compressor runs. i charged the refrigerant thinking the low pressure was tripping the dual pressure switch, still no good. i recently replaced my fusible links, so i am good there. where is the next spot to check, the dual pressure switch itself, the dash switch, the coolant overheat switch, the compressor fan? thx
 
PAJasper said:
ok, need a little help here. when i turn on my ac switch on the dash, nothing happens, no change in rpm, no click. just blows warm air.

i checked the glass tube fuses with multimeter, all good. i jumped the compressor, clutch kicks, compressor runs. i charged the refrigerant thinking the low pressure was tripping the dual pressure switch, still no good. i recently replaced my fusible links, so i am good there. where is the next spot to check, the dual pressure switch itself, the dash switch, the coolant overheat switch, the compressor fan? thx
Click to expand...
Page 4-109 might help...

Electrical Wiring (1987).pdf

drive.google.com drive.google.com
 
so the dash switch works, i can hear the condenser fan kick on (but no compressor clutch). so i think i am down to the engine temp sensor/switch, the dual pressure switch or the ac cutoff. having a hard time getting to pressure switch and engine temp switch. Do i need to take my seat out for both? I think i see in the manual that the pressure switch on the liquid line by the drier, but i can't seem to locate. the temp switch i beleive from the troubleshoot docs is on the thermostat housing, but I'm having a hard time getting there as well. thanks for keeping with me!
 
Does your refrigerant pressures cycle when charged and compressor clutch jumped? Wondering if you have a restriction in the expansion valve. If you can’t find problem in low pressure switch, observe compressor health by seeing if high side is really low and low side is really high. (Worn compressor)
 
i think what is happening is i have a hose without a gauge to start. i am jumping the compressor to feed the refrigerant. after loading a little guy can, i am pulling the charge hose off the fitting and disengaging the jump on the clutch, then using a hand gauge to measure pressure. So in essence, I am measuring static pressure, i think. It is in the 40s. From what i am reading, I am still a good ways off (should be around 100 psi), and may have not charged enough to engage the dual pressure switch? I thought i read that the low side needs to be above 33 psi to engage the pressure switch, so i thought that would have happened by now? I have also found the blue/yellow wire for the temp sensor, and it looks damaged with a bad plug. I am going to ground it to see if that is also part of the issue. more to come.
 
PAJasper said:
ok, need a little help here. when i turn on my ac switch on the dash, nothing happens, no change in rpm, no click. just blows warm air.

i checked the glass tube fuses with multimeter, all good. i jumped the compressor, clutch kicks, compressor runs. i charged the refrigerant thinking the low pressure was tripping the dual pressure switch, still no good. i recently replaced my fusible links, so i am good there. where is the next spot to check, the dual pressure switch itself, the dash switch, the coolant overheat switch, the compressor fan? thx
Click to expand...
My dash switch burned out and had to replace it 93 Delica L300 -
 
so after some fiddling around, and trying to understand why my wiring did not look like what I was hearing here or reading in the manuals, i figured out my blue yellow wire on the harness side that was intended to be plugged into the overheat sensor/shutoff was actually plugged into the black wire leading to the compressor clutch. disconnected blue/yellow, then bypassed (ran to ground), and reconnected the clutch wire to the newly found empty plug on the harness side that was actually the power intended for the clutch. adjusted refrigerant pressure, viola, have running AC. thx all.
 
Thank you everyone that posted here, you have helped me solve my A/C issue which I have been stumped on for a few days. Getting my 1992 L300 exceed filled up with r134a tomorrow by a shop in Abbotsford bc. Found this thread at 2:30am and am leaving to go in a cross BC trip tomorrow and this new experience of cold air in my van is going to work wonders. FWI it was my fusable link not being broken or unplugged but rattled out of its connection and hanging on by one little wire stran, I rednecked it just my doing a quick little solder on the fusable link to the exposed wire in the other side of the connector, will be buying another fusable wire when I get back home. Thanks again everyone!
 
PAJasper said:
ok, need a little help here. when i turn on my ac switch on the dash, nothing happens, no change in rpm, no click. just blows warm air.

i checked the glass tube fuses with multimeter, all good. i jumped the compressor, clutch kicks, compressor runs. i charged the refrigerant thinking the low pressure was tripping the dual pressure switch, still no good. i recently replaced my fusible links, so i am good there. where is the next spot to check, the dual pressure switch itself, the dash switch, the coolant overheat switch, the compressor fan? thx
Click to expand...
What's the process for jumping the compressor clutch?
 
Foxusmc said:
What's the process for jumping the compressor clutch?
Click to expand...


1710468967132.png

Per the Manual

MAGNETIC CLUTCH
(1) Disconnect the wiring to the magnetic clutch.
(2) Connect battery (- ) to compressor body.
(3) Connect battery (+) voltage directly to the wiring for the magnetic clutch.
(4) If the magnetic clutch is normal, there will be a "click". If the pulley and armature do not make contact ("click"), there is a malfunction.
 
In anticipation of recharging my L400 AC with R134, what is the proper way to deal with the can of refrigerant if the system doesn't need all of it? Should I just keep the gauge and hoses attached to with the needle fully plunged in the event I need it again?
 
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