No heat

Tiny
REBSTRKS1
  • 1999 FORD EXPEDITION
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 164,000 MILES

Frustrated, flushed core twice good water flow, pulled console door is working properly. Good heat from rear core. Puzzled, any ideas?

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Wednesday, January 11th, 2017 AT 11:48 AM

27 Replies

Tiny
HMAC300
  • EXPERT
  • 49,647 POSTS

Try pulling fuse in fuse box inside truck. It may be the blend door actuator messing up or a broken blend door. Pull for sixty seconds with key on then reinstall it may reset actuator and heat will work. If not check to see if actuator is getting power or not.

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Wednesday, January 11th, 2017 AT 12:04 PM
Tiny
JOHNNY G.JR
  • MEMBER

Check the heater control valve. It is vacuum controlled. Move lever on dash and see if control moves and check for vacuum at source and valve.

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Wednesday, January 11th, 2017 AT 12:07 PM
Tiny
REBSTRKS1
  • MEMBER

Pulled motor for blend door out working fine. Is there a control valve? Hoses go directly to heater core good water flow, water is circulating to rear core good heat from rear, puzzled?

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Wednesday, January 11th, 2017 AT 12:26 PM
Tiny
REBSTRKS1
  • MEMBER

Vacuum canister under dash near blend door motor, is this a control for water flow?

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Wednesday, January 11th, 2017 AT 12:32 PM
Tiny
HMAC300
  • EXPERT
  • 49,647 POSTS

No, it is a storage for the vacuum. If blend door actuator is getting power then it should open the door unless it's broken. If this is automatic temperature control it needs to be scanned for codes to see what is wrong.

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Wednesday, January 11th, 2017 AT 1:01 PM
Tiny
REBSTRKS1
  • MEMBER

Yes, automatic temperature, blend door is working fine. Thank you!

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Wednesday, January 11th, 2017 AT 3:31 PM
Tiny
JOHNNY G.JR
  • MEMBER

How was core flushed? Hoses left connected to heater core, water run in one hose and out the other. Are both hoses getting hot while running?

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Wednesday, January 11th, 2017 AT 9:43 PM
Tiny
SATURNTECH9
  • EXPERT
  • 30,933 POSTS

See if both heater hoses are getting too hot to hold? Are you sure the blend door is actually moving? The blend door shafts break and you see the actuator moving but the blend door itself is not moving.

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Wednesday, January 11th, 2017 AT 10:26 PM
Tiny
REBSTRKS1
  • MEMBER

Removed both hoses, used garden hose on both sides, flushed both directions with air first then water good flow with water, turned blend door with screwdriver works as it should, actuator is working air moves from vent to defrost to floor, good heat at rear core, hoses get warm but not hot to both front and rear hoses. New thermostat two months ago, puzzled wondering about water pump. Is it possible it is circulating enough to not overheat but not enough pressure to push through hoses for front heater core? Liquid takes the path of least resistance, I think I will try looping the rear hoses to see if this helps and will force the fluid through the front core only.

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Thursday, January 12th, 2017 AT 6:17 AM
Tiny
SATURNTECH9
  • EXPERT
  • 30,933 POSTS

The actuator that goes from floor to defrost is not the blend door that is the mode door. The door adjusts the the temperature from hot to cold.

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Thursday, January 12th, 2017 AT 6:38 AM
Tiny
SATURNTECH9
  • EXPERT
  • 30,933 POSTS

There is your heater valve. I posted a picture of it.

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Thursday, January 12th, 2017 AT 6:44 AM
Tiny
HMAC300
  • EXPERT
  • 49,647 POSTS

Guys, it automatic temperature it may be a sensor bad. See pictures on how to enter and exit self test for automatic temperature control then get back with codes if any. Also, check for vacuum leaks at vacuum motors.

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Thursday, January 12th, 2017 AT 6:44 AM
Tiny
SATURNTECH9
  • EXPERT
  • 30,933 POSTS

I posted a picture if the blend door actuator. It still has coolant going in and out of the heater core blend door actuator etc. Those are basic checks ether way it is automatic or manual controls.

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Thursday, January 12th, 2017 AT 6:48 AM
Tiny
JOHNNY G.JR
  • MEMBER

Is engine reaching normal operating temperature? Are heater hoses free of obstructions? Is return side heater hose collapsing possibly? Is heater valve opening completely? I think HMAC is on to the cure REBSTRKS1.

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Thursday, January 12th, 2017 AT 10:09 AM
Tiny
REBSTRKS1
  • MEMBER

No heater valve. Heater core comes through firewall hoses hook directly to core. Cannot find a heater valve unless it is behind the firewall, but hoses hook directly to core? Hoses are warm so the water is circulating, but no heat to cab. I have tried everything you have mentioned. That is what is so frustrating!

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Thursday, January 12th, 2017 AT 11:38 AM
Tiny
SATURNTECH9
  • EXPERT
  • 30,933 POSTS

The hoses going into the heater core are too hot to hold? Also, are there any codes?Let's put that to bed right now? Also, your sure the blend door is actually moving and the actuator is not just moving a broken part of the blend door?

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Thursday, January 12th, 2017 AT 12:41 PM
Tiny
SATURNTECH9
  • EXPERT
  • 30,933 POSTS

The shaft on the blend doors do break, it is not uncommon for them to break. They even make a repair kit so you can fix it through your glove box so you do not have to pull the heater box.

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Thursday, January 12th, 2017 AT 12:43 PM
Tiny
REBSTRKS1
  • MEMBER

I Thank You all for the help, still puzzled, tried every thing I can think of, OK flushed heater core twice good water flow and no leaks, hoses getting nice and warm as they should, looped hoses to rear core to ensure water is flowing through front core, pulled console out actuator motor working fine, turned blend door with stubby screwdriver it is diverting air to floor, vent, defrost as it should, controls for automatic seem to work fine, no codes coming up on self diagnoses, I had to step back and think about this awhile ( also have good vacume at canister and no vacume leaks ) wondering about separate door other than blend door? Is there a separate door to let air flow across heater core? Any ideas Thanks again everyone I appreciate the help

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Friday, January 13th, 2017 AT 3:54 PM
Tiny
HMAC300
  • EXPERT
  • 49,647 POSTS

You did the wrong actuator, the blend door moves air across heater and or a/c have a pro look at this.

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Friday, January 13th, 2017 AT 4:28 PM
Tiny
REBSTRKS1
  • MEMBER

NO I Don't give up that easy, and did a pro learn by giving up

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Friday, January 13th, 2017 AT 5:28 PM

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