Cant control temperature
 

I have an 87 gmc 3/4 t0n . Lately the temperature seems to be max heat no matter where I set it. Cable seems to be working, is there a vacuum control connected to it somewhere. It does have AC but its not working at this time. If anyone can help it would be much appreciated.

Re: Cant control temperature
 

There is a vaccum line the runs from the manifold through the firewall just above the trans dip stick. Check to see if its cracked or broken. The one on my 85 was broken and just hanging there. However there is two vaccum actuators on the heater box. One is next to the gas pedal and the other is between the box and firewall. The box has to come out to get to it. I hope this helps.

Re: Cant control temperature
 

Problem solved. It was just the cable had slipped off of the lever. Thanks for the help . Us dogs have to stick together.