AC clutch is always engaged
 

Hello everyone,
I am new here and am looking for some help. I bought a 1999 F150 4.6 4x4 recently that is giving me some problems. (I got it on the cheep and new it needed some repairs)

The current problem is the AC compressor. The system wasn't charged when I bought it a month or so ago and last week the compressor started smoking. I replaced it with a brand new one, including the clutch and pulley, accumulator and orifice tube. I never got the chance to charge the system because the first time I drove the truck the new compressor started freezing up. I took it back and exchanged it and put the new one in. This time I paid attention and the clutch engages as soon as I start the truck. The AC controls are off and there is no freon in the lines.

So, my question is what could cause this to happen? Any help is appreciated.

Thanks in advance for the help.

Does it have automatic climate control? My last truck, (98 Blazer), did, and it would do that s*** too and it drove me nuts! Not entirely sure what's causing it, but I would go ahead and charge it before it burns itself up and seizes up. No freon, means no oil. Good luck with it!

I already burned one up and am in the fortunate position of not having to drive this truck right now....and if I did I would just pull the plug on the clutch and it will disengage.

Not sure what you mean by 'automatic climate control'. I have found that when I pull the high and low pressure switches and even the clutch relay that it doesn't change anything so I think what I am going to have to do is just trace the wire from the clutch and work my way back to the fuse from there. I am now guessing that I have a short somewhere that is either powering up the line OR (I just realized) it might be a switched ground that is shorting out.

I guess we will see.