Heater does not blow hot air

2004 LEXUS ES 330
190,000 MILES • 2.8L • 6 CYL • 2WD • AUTOMATIC
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BILLHOLDER
  • MEMBER
  • 1 POST
Air conditioner and thermostats work. When you turn to heat it blows cold air.
Oct 16, 2018 at 9:02 PM
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JACOBANDNICKOLAS
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 110,190 POSTS
Hi and thanks for using 2CarPros.com.

In most cases, the lack of heat can be attributed to one of two things, the blend air door or a plugged heater core.

First, I have attached a picture of the heater/AC unit for you to see. It identifies the components related to the system. The first thing I need you to check is if both heater core (heater radiator) hoses are getting hot when the engine is at operating temperature and the heater is on high. The attached picture are the components under the dash. The heater core (radiator) pipes go through the firewall and into the engine compartment. There will be a rubber heater hose attached to each one.

If both heater hoses are hot, most likely the problem is related to the blend air door actuator (AKA air mix damper control servo motor) There are two, one for each side.

Let me know what you find or if you have other questions.

Take care,
Joe
Oct 17, 2018 at 5:08 PM
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