So i live in wisconsin and its about -2 out right know and i got a little problem.When my car is running my heater only pumps out cold air. the tempeture guage in me dash is malfunctioning to0. it keeps telling me that the car runs at dead cold.and the heat dosent work but when the guage does kick in the temp will go up a lil bit not even normal operating temp and my heat will start to pump out. i am thinking its that guage but what would that matter if it pumps out cold or hot air id appreciate the help Thanks

 

My girlfriends 94 100 S is doing the same thing. If she lets it sit and idle for a long time the gauge will go up some and it gets warm inside but as soon as she starts driving it the gauge goes back down to cold and no more heat comes out.

 

Sounds to me like your themostat isn't working.

 

I would think if the thermostat was stuck open it would not warm up at all and I know it has been replaced twice. I will have to get more details she is up in MN and I am down in TX