Air Conditioner is not blowing cold air

[Northrunner]

Hi Guys,

So I thought I would try refreshing my A/C system with a can of R-134a, hoping that would fix my "no cold air" problem. I have a Refridgerant Recharge Hose w/ gauge that I've used successfully in the past w/ refrigerant canisters.

Today though, I could not get the R-134a canister to unload into my system. I had the truck running with the A/C on Max Air. I screwed the canister onto the recharge hose, then attached the other end to the recharge nipple (just in front of the firewall on the passenger side) for my system. Then screwed down the knob that lowers the needle that punctures the canister, then screwed it up again to get the needle out of the hole.

At that point I expected the canister to be emptying into my system, but it did not empty at all. And what's weird is the gauge needle was reading 75 PSI when the "Green Zone" on the gauge is from 25-55 PSI. Then I unhooked everything and put it all back on again and then the damn gauge needle just pointed at 6:00 not moving like it is broken. Maybe it is and I'll probably buy a new gauge and try again.

Am I trouble-shooting this in the right way? Any advice?

Thanks in advance,
Northrunner
1998 3500 White Quad Cab Dually, 12 Valve, 5-Speed, LS, 175,500 miles

 

[DavidC]

You may have to jumper the low pressure switch to get the clutch to engage. I have done that many times. On my 99 it is at the dryer near the passenger side firewall with a green plug.