GMC SAFARI HEATER

Would A Bad Heater Core Cause No Heat?

1998 Gmc Safari Heater Works In Summer Blows Cold In Winter New Thermostat, Switch, Still Blows Cold. New Fluids Also

1994 Gmc Safari My Van's Heat Is Blowing Out Cold Air. I Put Water In It And It Still Didn't Heat Up Whats The Problem?

The Rear Heat Does Not Work Any More. It Blows Cold Air. Could This Be A Rear Heater Core Problem? If So, Where Is It Located And How Can...

Selector Switch For Changing From Floor To Dash To Defrost Doesn't Work. Is There Any Common Reason For This Condition?