Air won't shut off

My A/C won’t switch to heat. Coolant level good. Fan and all other systems work fine. Engine temp normal.When I turn to heat the A/C compressor still runs and blows cold air. I don’t know if it’s related but about the same time this problem started the truck quit starting on the first try, especially when cold.

For the time being, pull the A/C fuse…

Assuming that your ranger is somewhere in the 2000 to 2011 range (it’d be nice if you would tell us the year)…

The compressor will still run in a number of the settings other than AC or MAX AC. It shouldn’t run in the floor only setting.

Two things control getting heat. The first is the vacuum controlled heater valve. When you select heat (by turning the temperature dial towards red and having the control off of MAX AC), the vacuum to the heater control valve is vented and the plunger on the vacuum servo extends and opens the valve. The valve is in the middle of one of the heater hoses over the engine. Check and see if it opens and closes. If it doesn’t open, pull the vacuum hose off and see if it opens. If it does, then your controls are messed up. If it doesn’t, then the valve is stuck closed. You can probably pull it open.

The second thing that controls heat is the blend air door. It is operated by an electric servo motor that responses to the position of the temperature dial. It’s not unheard of for some of the plastic pieces that move the air door to break. The parts are fairly cheap, but the labor to take apart the dash to replace them isn’t.

It won’t help. Even with full AC selected, the heater core could easily over power the AC and put out very hot air. The OP’s problem is elsewhere.

Thanks for the tips. BTW it’s an '08. The valve in the heater hose opens and closes as it should. Any suggestions on where to find more info on the blend door? Also any tips on the starting situation mentioned earlier. Again,THANK YOU!!

Do you have the defrost button on?

In the 2 years i’ve had this truck I haven’t seen a defrost button yet!

That’s because it doesn’t have one. It does have a defrost position that you can turn the selector knob to.

Okay, check and see if both heater hoses get hot when the heater valve is open (plunger out). If so, that points strongly to the blend air door or (if you are lucky) the temperature control. The forum below may be of some help for details.