No heat

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.

This guide can help as well

https://www.2carpros.com/articles/car-heater-not-working


Please let us know what happens.

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.

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 ?

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

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.

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

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?

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.

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.

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.

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

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.

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.

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.

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!

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?

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.

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

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

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

The blend door actuator is behind the center of the dash.

Do you have to pull the dash, or is this the one they say to pull the glove box to get to easier?

There is a vacuum canister is it vacuum controlled?

No it's a electric actuator and the glove box part is if your replacing the blend door with the dorman repair kit.

Should be able to see it to the left side of the glove box up under the dash

Ok I will find it, that has to be the problem, it's the only thing that makes sence THANK YOU

Your welcome make sure you check the shaft of the blend door to see if uts broken

The heater isn't blowing out any heat. I am researching and I keep finding its my heater core is what keeps popping up but the truck never over heats. with my experience with vehicles is that a heater core blows out steam through the defroster vents and then heats up the engine real fast. stuck we just got this SUV too. stumped.

first, check the heater hoses at the core. they both need to be hot. if one is hot and one cold, the heater core is clogged.

if they are both hot, then the blend door motor has failed.

Roy

Ok if its clogged how do i fix it do i just replace the core? And if its the blend door how do I fix that. I dont trust many mechanics in my town. If I can do it I will.

you can flush the heater core by using a garden hose and flow both ways.

the blend door motor is much tougher.

Roy

1999 Ford Expedition Four Wheel Drive Automatic 130000 miles

Hi. I have a 1999 Ford Expodition and the A/C works great, but when you switch it over to the heater it still blows cold air. I was woundering if you could help me. I;m guessing its the theromstat or the heater door not opening. not sure.

yes it is more than likely a mixing door . and they will have to take the dash apart. but I would definitely get several opinions. the dealer is very very expensive and you could save several hundred dollars, going elsewhere. so check it out.

Warm up car turn the heat on then it blows hot air then immediately turns cold.

Feel the heater hoses at the bulkhead when the engine is hot. Both hoses should be hot. With the engine running, move the temperature control lever/**** completely both directions. You should hear the blend doors in the airbox moving. If not, check the connections, wiring, and vacuum lines. Make sure the vacuum lines are drawing a vacuum. If so equipped, make sure the heater control valve just inside the engine compartment is operating properly when the temperature control is moved. Make sure the cooling system is full and the thermostat is operating properly (look in the radiator with the engine one and at temperature-this will also tell you if the water pump is working properly).

When is heater **** is all the way to heat with high fan it blows cold air.

The first thing i would do is make sure both your heater hoses going into the heater core are getting really hot when the engine is up to normal operating temp.

my heater will not get warm...

no, and I believe I just addressed your heat issue.

Roy

What can a backyard mechanic do to fix or replace the heater core. How can i disconnect the power for my heater core for the mean time, till i am ready to have it fix....