2003 chevy 1500 ss only blows cold air no heat

SOURCE: Heater only work on high

Most likely is the resistor when they fault the default to high giving you off and high only

SOURCE: blowing cold air

I had the same problem that I just fix by flushing the heater core out with a hose.   take the two hoses off the fire wall and put the water to it and let flush.  my heater is putting out 150 dg. F  of hot air.   I'm so excited!  i will stay warm now.

SOURCE: 2004 chevy silverado 1500 a/c heater

when my truck is at an idle, it won't put out any heat in the cab, same thing in the summer with the A/C, what's the fix for it ?

Jeffery Lewis

• 329 Answers
• Posted on Jun 03, 2009

SOURCE: 2004 Chevy Silverado AC is blowing warm air on passenger side.

You have dual zones that are controlled by temperature actuators the passenger side has lost its memory or has gone bad you can put it in self programming by disconnecting the battery for ten minutes then hook it back up start the truck turn the temperature control on but do not touch any other controls let it go thru the self programming for about 6 to 7 minutes then select your temperature you want if it still does not work properly you may have a bad actuator or a bad connection at the actuator

SOURCE: 2004 chevy tahoe, dual climate control, blowing different temps

Its more then likely the temp door broken or temp door motor broken/stuck. There is 2-3 of these motors under the dash on the side of the evap/heater core box. Some require extensive labor to replace, good luck