Heating / air conditioning

The heat in my truck pours hot air all the time, even with the outside air vent selected. I have to drive around, even now with the A/C on to keep the cabin a reasonable temp. My shade tree mechanic hasn’t a clue, and the local Mazda dealer hasn’t a clue ! Help me I’m being roasted alive ! AAAAEEEEEEEEE !! This truck was purchased new by me in 1998 with no other problems over the years ! Great truck other than this and I will keep it until I can’t handle the big shifter any more !

Do you mean that you put the car in both the independants and the Dealers hands and they returned it to you with the explaination that they could not diagnois the condition?

Yes ! The reply was that it could be a control device in the wheel well might be to blame but the vacuum switch that controlled the heat was working properly, they checked the duct work and it seemed to be working. I asked them if they drove it and neither had nor would send a service guy to do it . It’s winter now so I’m using forums to see if anyone else has had this type of problem. 96000 original miles all driven by me and this is the FIRST problem I’ve had with this truck. Otherwise a great vehicle that I will keep the rest of my life and give it to a grandson when he can drive. We have a 46 Buick we are working on right now that will go to him (I HOPE ) George

latest development is , turn on AC run for 5 minutes then switch to heat. After a dozen tries at this, it finally works and I’m so not going to touch the control !

Sounds like a busted blend door.

Heres a link that should help


Is this truck a Ranger-like vehicle. I remember that Rangers had heat controlled by valves rather than blend doors until relatively late.

Open your hood and follow the heater hoses to the firewall. One of them will have a petcock (valve) controlled by a wire that goes up to the heater control in the dash. It is either out of adjustment or simply wont close.