The heater puts out very little heat

1998 DODGE RAM
168,000 MILES • V8 • 2WD • AUTOMATIC
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LOWKEE
  • MEMBER
  • 47 POSTS
i have a 1998 dodge ram 1500. the heater puts out very little heat. i have replaced the thermostat, flushed the heater core, checked the vacuum lines, filled the radiator, purged for air in lines and checked all doors. however, when you move the selector knob to the air conditioning setting and have the temperature control knob in the heat position the heater works alot better. why? and how can i fix it.
Jan 1, 2010 at 5:04 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,246 POSTS
There is a blend door that isn't working correctly. It is what determines if you get heat or AC. When you put the ac on with the heat, it's allowing the air to pass the heater core too. Check it first. It is near the heater core.
Apr 23, 2021 at 4:02 AM
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LOWKEE
  • MEMBER
  • 47 POSTS
i ended up replacing the water pump and it worked fine
Apr 23, 2021 at 4:02 AM
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