Air Conditioning Help

[Boone83K10]

Ok I have had two people want to buy my truck (yes it is for sale, baby on the way). Both of them backed out when I said the AC does not work. I don't know what the big deal is since you do not need it in my area. It was only 61 today for the high. Anyway....

I did some testing on it. I put the control head on AC MAX high. The compressor clutch does not engage. I pulled the low pressure switch connector off and jumped the dark green wire to the battery. The compressor did not engage. I put a test light on the idle solenoid plug and it is getting power (although the plug is just there and there is no idle solenoid).

Why would the idle solenoid plug get power and not the compressor? Are they not run from the same wire and just split off at the plug near the firewall?

What other tests can I do? Should I check the blower switch (it looks original)? Should I change the blower motor relay?

PS----- the truck has already been converted to R134-A before I bought it. I have no idea if it has any refrigerant in it. Would that cause it not to engage even when I jumped it?

 

[Boone83K10]

ok I did some more testing.

I am not getting power to the dk green wire at the compressor. Now, I know that it won't engage at the low pressure switch unless the compressor has built up enough to energize it. So I guess I will have to make another jumper wire and then test at the compressor to see if it is actually working.

 

[Boone83K10]

AH HAAA!!!!!!!!!!!

I used a jumper wire and put it in the low pressure switch plug. I then put the test light onto the dark green wire at the compressor. It lit up!!!!!! I plugged it in and heard a click! Fired up the truck and the clutch was turning like a champ. I am going to go buy some R134A right now and put some in it. I am hoping it is just low and that is why the LP switch won't engage the compressor.......

I guess I did it wrong yesterday when I was testing. I obviously plugged it back to the LP switch then tried to test the compressor wire, which wouldn't have worked anyway.

 

[Stroked]

Glad you got it figured out. Lol. I don't know much about a/c so I was no help. Sounds like its low though and not letting the compressor kick on.


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[Boone83K10]

I have put 36 oz worth of 134 in it and it stays on for 15 or so seconds then cycles off then back on...

I cannot read my R12 sticker to know how much to put in. Ive read on internet that it calls for 5.25 lbs which would be 84 oz. I know you are suppose to put only 85% R134 in a converted R12 system since it operates at higher pressure.


So how much does your sticker say to refill to??? I have 83 K10 Silverado with the R4 system that is converted to R134a

 

[Boone83K10]

another question is what should I be idling at when it's on full blast? I don't have a high idle solenoid.

 

[Stroked]

I just checked and all the stickers are missing off of my a/c so I'm no help there either


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[Boone83K10]

I have put 5 cans in now, it is nice and cold. No more cycling on the compressor. At 60 oz, it seems like a lot but if the 5.25 lbs is correct, which is 84 oz... I can still put in about half a can.

Meanwhile, my electric choke quit all the sudden and I had to fix that last night! I also decided not to sell my truck. Too valueable in the long, snowy winters of Boone, NC.

 

[89Suburban]

Good job

 

[cedens]

i found a can of R12 behind my seat, thing is we converted to 134A back in 94, Checking the A/C the switch is going bad i think the blower thankfully is easy to remove under the hood, but you have to hit the switch just right to get the blower on full blast.

I may head to town in the morning and get some 134 A seen a whole shelf of it for cheap at one store.

I definitely need a new switch, the system has been clunky since the heater core change back about 1992.

 

[philjafo]

Might try putting that can of r12 up for sale, r22 hasn't been made for a long time and a car restorer might absolutely have to have it for his perfect restoration.

 

[bucket]

Burbs with dual AC are the ones that hold over 5 lbs. Trucks are less and somewhere I have a booklet that lists the charge amount for most every vehicle since the late 70's.

 

[cedens]

This stuff?

No clue why it was behind the seat, it was converted back when i first drove it when i was 16

 

[chengny]

Refrigerant Capacity - C/K Series: Kg. 1.6 / 56 Oz.



That weight (in ounces/Kg) = about 4 1/2 cans.

 

[cedens]

Put 3 12 oz cans of reg R134 and on 10 oz can of 134 with stop leak, ac down to 59... not sure but we used to get it down to 34, could have been the old stuff made it colder.

but the compressor will kick on and off under low refrigerant pressure, once it kicks on and stays on you are nearing proper pressure.