Heater always on

I am constantly getting heat, from the heater, coming in on the passenger's side. I am unable to turn it off. Any suggestions on what I can do to turn it off? Heater controls are all the way to the left. Even when the A/C is on I get heat. Any suggestions?

There is a vacuum operated valve under the hood that turns the hot water off, check for vacuum at that valve.

The valve is on the coolant hoses neer the pasenger side firewall. Early 4.0(87 to maybe91) has only 2 hoses as I remember while the later ones have 4 with a small vaccume line as well.

there is also a cable on my 93 that runs under all the ducting in the passenger side to operate a damper, it can get kicked and messed up.

be careful with that 4 way vacuum valve under the hood, it gets real brittle, mine busted. i replaced it with a barbed connector and a valve. turn it off in summer, on in winter.