GMC C3500 Heater Not Working

Number 5 On The Heater Control Doesn't Work. One Through Four Works Fine As Do All The Other Features. I Used A Test Light On The Electrical...

Heater Problem 1993 Gmc C3500 V8 Four Wheel Drive Automatic Winter Is Comming Up And After Freezing Last Winter I Want To Be Warm. My...

I Have Weak Heat In A 84 Gmc. I Have Replaced The Heater Core And Thermostat, The Supply Hose From The Core Is Hot, The Return Hose From The...