Mechanics

NO AC LIGHT COMPRESSOR NOT ENGAGING

1997 Chevrolet Suburban • 175,000 miles

I am trying to get my 97 K1500 Suburban AC working. When I purchased the truck, I new that the AC did not work. The previous owner told me that the compressor locked up, so he changed to the shorter belt and moved on. Now that I've moved to FL, I need the AC. While changing out everything I found that the rear ac has been disconnected and the shared pressure hose obviously changed out. I bought all new parts (accumulator, compressor, condensor, low pressure switch, high pressure switch and orafice tube filter). I'm not gonna worry about the rear air, I'll just be happy to have the front ac working at this point. Now that I have everything installed on the truck, I vacuumed out the system and it holds. The problem that I'm having is that my dash light is not coming on and the compressor is not engaging. I checked and I have no power at the low pressure switch. Checked all fuses and relays, everything is good. I'm not sure where to go next. I've read several things about checking the control head in the dash, which I may try next. This may also be relavent, the 1st and 3rd settings don't work on my fan settings.
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Czr1760
July 28, 2012.




Yep we're good, I am hooking it up as a no rear ac system. No oil came back out of compressor when I took off to re-install cycle switch. How much should I put in to start?


Tiny
Czr1760
Jul 28, 2012.
I have aprx. 3.5 oz of liquid & also have 3 oz of aresol.


Tiny
Czr1760
Jul 28, 2012.
Do you have a vacuum pump to pull a vacuum on the system you really need to do that do get all the moisture out I would vacuum it fo atleast 45 mins.


Saturntech9
Jul 28, 2012.
Yes, I have a vacuum. I was going to do that, but I was waiting to see how much oil you wanted me to install first. I think I'm going to put in 2 oz liquid and vac the system. Where should we go after that?


Tiny
Czr1760
Jul 28, 2012.
Heres what I do vacuum the system thru my manifold gauge set thru the high and low side then turn off the manifold valves. Let it sit for about 5mins to see if the gauges rise if they dont rise then I add oil.I suck the oil thru low side of the manifold gauge set thru the middle yellow charge hose.I would add about 7ozs of oil since you changed a bunch of stuff and had a blow out on the compressor. Also add oil with dye in the oil. Dont add stop leak that plugs things up. As far as charge goes without rear air it holds 3LBs which would be 48ozs So 4 of the 12oz cans.
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Saturntech9
Jul 28, 2012.
Ok, I added the liquid oil (aprx 3.5 oz)and will add the 3 oz aresol once the system is vacuumed out. I have 3 cans of freon left, but can I add this without having any power? I'm going to check all plugs for power with & without key on.


Tiny
Czr1760
Jul 28, 2012.
What plugs are you checking for power?The ac clutch wont have power till you have enough charge in the system. The ac compressor will cycle when it first comes on. But this will help to pull the charge in till the compressor stays on.


Saturntech9
Jul 28, 2012.
With key on, ac button pushed & truck off. I have no power to compressor, high pressure or low pressure switch. I do have ower to cycle cut off switch.


Tiny
Czr1760
Jul 28, 2012.
So are you saying that I should try and charge the system, even though I don't have power at most of my switches?


Tiny
Czr1760
Jul 28, 2012.
Heres what I said earlier maybe you didnt see or read it so here it is again. Also the a/c high pressure cutout switch on bottom rear of the ac compressor and the ac compressor cycling switch on top right of the ac accumulator. Those switches the black wires with a white strip go to ground thats why there is no power there switches. If you had power also you would have a dead short to ground. Also as far as your ac clutch that wont get power till there is enough pressure in the ac system.


Saturntech9
Jul 28, 2012.

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