1997 Explorer Heat Suddenly Stopped Working

[flynniep]

1997 Ford Explorer Eddie Bauer 4X4.
So I've had this car for about a month, it has only one previous owner, impeccable service history and only 90,000 miles on it.
Recently, the power steering went out and the auto shop repaired the pump, pulley, pressure line, fluid and freight parts.
When I dropped the car off the heat was working 100%, when I picked it up it was still warm from the day, so I didn't notice the heat wasn't working until later that night when it dropped down to 30 something outside.
I brought it back into the shop and the guy who did the power steering repair looked at it, all he did was open the radiator cap and leaked fluid onto the ground, then grabbed a flashlight and peered at the thermostat for 5 minutes, checked the coolant levels and then gave me this really vague "hmm well it could be the radiator, could be the water pump, could be the thermostat, not sure until I take it apart"... The radiator is fine, the car hasn't been overheating, the coolant levels are fine, and the system check says the engine temp is ok. So I know they're trying to rip me off, mind you when I came in for the power steering, they told me only the pump would need replacing, and then I walked out $800 later... They also argued with me back and forth about driving the car off the property without getting the radiator replaced...
So I took it to another shop where the guy got into the car, looked at the fuse box, messed around with the temp controls, went under the hood and felt the temp of the water hoses, and said that it was most likely a stuck blend door in the dashboard since there is hot water flowing through.
Has anyone else experienced this issue with this year and model and what was the diagnoses and outcome?
Thank you!

 

[974X4BLACKSPORT]

Try checking the vacuum operated heater control servo. If the servo does not open when you turn the "temperature" knob on the climate controls to "HOT", hot water will not flow through the heater core, and you will then not have hot air coming out the vents in the cab.

 

[96eb96]

Try checking the vacuum operated heater control servo. If the servo does not open when you turn the "temperature" knob on the climate controls to "HOT", hot water will not flow through the heater core, and you will then not have hot air coming out the vents in the cab.

Or feel upstream heater hoses between the core and the valve. If they are both cold, there is no heat.
Blend door/motor is a possibility.
The way the blend door breaks sometimes will not give codes on the EATC self test.

 

[flynniep]

Or feel upstream heater hoses between the core and the valve. If they are both cold, there is no heat.
Blend door/motor is a possibility.
The way the blend door breaks sometimes will not give codes on the EATC self test.

Both of the hoses are hot, I’m thinking it is the blend door. I looked and it’s in my glove compartment, the thing is my specific car was a fire rescue vehicle, so there are two siren switches in the glove compartment, how would I go about removing the compartment without damaging those switches?

 

[flynniep]

Try checking the vacuum operated heater control servo. If the servo does not open when you turn the "temperature" knob on the climate controls to "HOT", hot water will not flow through the heater core, and you will then not have hot air coming out the vents in the cab.

I had the vacuum looked at by a mechanic and he said all was fine there, as well as both hoses flowing hot water. He said it was something inside the dashboard and I did some research and found that can be a very expensive repair. I would rather save money on labor costs. What are the possible issues that lie within the dashboard that I could troubleshoot myself? I’ve done some minor repairs on my old car, like brakes, O2 sensor, turn signal, headlight, etc

 

[fast_dave]

@flynniep

Forget the mechanic and do this simple test yourself

Sounds like something simple since it was working one moment, then it stopped - so my vote is with what forum member @974X4BLACKSPORT wrote.

OK - on an OHV V-6 the vacuum controlled hot water valve is in the picture BELOW with a screwdriver manually holding down the vacuum arm so that I could drain all of the coolant from the heating system while performing a change of heads.

So when that arm is DOWN, the valve is open and hot coolant is passing through it, and then into your cabin heater core (radiator).

When the arm is UP, the valve is closed and coolant is prevented from passing through it - so no hot water reaches your cabin heater core.

Start your Ex, let it idle, turn on the heater knob to choose floor heat, and then have someone turn the temperature dial slowly between cold/blue to hot/red.

If you are getting vacuum to the valve, the arm should be going up and down.

If the arm isn't moving, preform the same procedure, but with the top vacuum line removed from the hot water control valve, wet your fingertip, and hold it against the 90 degree rubber angle, and see if you can feel a vacuum being pulled as someone in the cabin is twisting the temperature control valve (I'm assuming you don't have a vacuum gauge - if you do - you can plug that into the 90 degree rubber angle).
If you are getting vacuum, and the arm isn't moving, then this valve is bad, and you need a new one.

Now if you are getting vacuum, and the vacuum controlled hot water heater valve arm is moving up and down, then your next investigation is around the operation of the door blend motor inside the cabin...

Let us know!

 

[flynniep]

@flynniep

Forget the mechanic and do this simple test yourself

Sounds like something simple since it was working one moment, then it stopped - so my vote is with what forum member @974X4BLACKSPORT wrote.

OK - on an OHV V-6 the vacuum controlled hot water valve is in the picture BELOW with a screwdriver manually holding down the vacuum arm so that I could drain all of the coolant from the heating system while performing a change of heads.

So when that arm is DOWN, the valve is open and hot coolant is passing through it, and then into your cabin heater core (radiator).

When the arm is UP, the valve is closed and coolant is prevented from passing through it - so no hot water reaches your cabin heater core.

Start your Ex, let it idle, turn on the heater knob to choose floor heat, and then have someone turn the temperature dial slowly between cold/blue to hot/red.

If you are getting vacuum to the valve, the arm should be going up and down.

If the arm isn't moving, preform the same procedure, but with the top vacuum line removed from the heater control valve, wet your fingertip, and hold it against the 90 degree rubber angle, and see if you can feel a vacuum being pulled as someone in the cabin is twisting the temperature control valve (I'm assuming you don't have a vacuum gauge).

Hope that helps - if you are getting vacuum and the vacuum controlled hot water heater valve arm is moving up and down, then your next investigation is around the operation of the door blend motor inside the cabin...

Let us know!



View attachment 328394

Thank you so much, this was very informative! I’ll post back once I’ve tried this!

 

[fast_dave]

Thank you so much, this was very informative! I’ll post back once I’ve tried this!

Sounds great - looking forward to hearing you hit your goal!

 

[flynniep]

@flynniep

Forget the mechanic and do this simple test yourself

Sounds like something simple since it was working one moment, then it stopped - so my vote is with what forum member @974X4BLACKSPORT wrote.

OK - on an OHV V-6 the vacuum controlled hot water valve is in the picture BELOW with a screwdriver manually holding down the vacuum arm so that I could drain all of the coolant from the heating system while performing a change of heads.

So when that arm is DOWN, the valve is open and hot coolant is passing through it, and then into your cabin heater core (radiator).

When the arm is UP, the valve is closed and coolant is prevented from passing through it - so no hot water reaches your cabin heater core.

Start your Ex, let it idle, turn on the heater knob to choose floor heat, and then have someone turn the temperature dial slowly between cold/blue to hot/red.

If you are getting vacuum to the valve, the arm should be going up and down.

If the arm isn't moving, preform the same procedure, but with the top vacuum line removed from the hot water control valve, wet your fingertip, and hold it against the 90 degree rubber angle, and see if you can feel a vacuum being pulled as someone in the cabin is twisting the temperature control valve (I'm assuming you don't have a vacuum gauge - if you do - you can plug that into the 90 degree rubber angle).

Hope that helps - if you are getting vacuum and the vacuum controlled hot water heater valve arm is moving up and down, then your next investigation is around the operation of the door blend motor inside the cabin...

Let us know!



View attachment 328394

I have another question, my glove compartment is equipped with two siren switches as it used to be a fire rescue vehicle, so if it does come to replacing the door blend motor which is behind my glove compartment, how would I remove it without damaging the switches/how do I disconnect the switches. There are two 180K Unitrol switches.

 

[fast_dave]

Couldn't tell you without seeing.

Picture are worth 1,000 words.

The add a picture feature is activated in the reply box - it's in between the "figure 8" and the "smiley face"

 

[flynniep]

Couldn't tell you without seeing.

Picture are worth 1,000 words.

The add a picture feature is activated in the reply box - it's in between the "figure 8" and the "smiley face"

I ran the vacuum test and the valve arm is moving correctly, as well as the vacuum pressure, both hoses are moving hot water. The only thing it could be is the blend door actuator right? I located it, you’ll see it in the photos, I just can’t remove the glove compartment without removing the switches first. Thank you!

 

[flynniep]

This is a video of my glove compartment.
I ran the vacuum test and the valve arm is moving correctly, as well as the vacuum pressure, both hoses are moving hot water. The only thing it could be is the blend door actuator right? I located it, you’ll see it in the video, I just can’t remove the glove compartment without removing the switches first. Thank you!

 

[fast_dave]

@flynniep

OK - those pics are worth 1,000 words

Pretty sure you have a blend door issue.

I replaced mine at 190,514 miles in May 2016 = 18 years service life.

Simply unscrew (lefty -loosey) the thin nut that secures the switch (one is already removed), and then push the switch through the plastic glovebox.

Disconnect switch(s) from wiring, snip off exposed copper wire, and then wrap the end of the wires in electrical tape so they don't come in contact with anything = done deal. If you want can, find a place to safely zip tie them to so they aren't dangling.

OR - you could just leave the switches hooked up to the wires and zip-tie them off.

I don't know what your mechanical level is with the black art of electrical systems, so I'm just keeping this simple for you.
I have no idea what those switches were for/what they control, I'm guessing the equipment was removed, so maybe there's no power to them?!?!?!

Follow YouTube Video Instructions as how to replace blend door:

You can find reasonably priced blend doors on Ebay or Rock Auto.

They're all made by the Chi-Coms so they're basically all the same BUT it's a "mature" aftermarket part so it gets the job done.
No need to spend wads of $$$ on one.

PS - there are (3) tiny bolts that hold down the blend door - one you can't see - it's all "feel" with that one - you'll have to become one with the bolt. Read the comments in the YouTube video - there's a few about that bolt

At Approximately 1:50 in the video el dudearino talks about it. Work very carefully with that bolt - many lose it - work during the day when the sun is out and you aren't stressed for time.

The blend door will work with (2) bolts - but just sayin'

Welcome to the forum, report back and good luck!

Take some pics of your repair for posterity

 

[flynniep]

@flynniep

OK - those pics are worth 1,000 words

Pretty sure you have a blend door issue.

I replaced mine at 190,514 miles in May 2016 = 18 years service life.

Simply unscrew (lefty -loosey) the thin nut that secures the switch (one is already removed), and then push the switch through the plastic glovebox.

Disconnect switch(s) from wiring, snip off exposed copper wire, and then wrap the end of the wires in electrical tape so they don't come in contact with anything = done deal. If you want can, find a place to safely zip tie them to so they aren't dangling.

OR - you could just leave the switches hooked up to the wires and zip-tie them off.

I don't know what your mechanical level is with the black art of electrical systems, so I'm just keeping this simple for you.
I have no idea what those switches were for/what they control, I'm guessing the equipment was removed, so maybe there's no power to them?!?!?!

Follow YouTube Video Instructions as how to replace blend door:

You can find reasonably priced blend doors on Ebay or Rock Auto.

They're all made by the Chi-Coms so they're basically all the same BUT it's a "mature" aftermarket part so it gets the job done.
No need to spend wads of $$$ on one.

PS - there are (3) tiny bolts that hold down the blend door - one you can't see - it's all "feel" with that one - you'll have to become one with the bolt. Read the comments in the YouTube video - there's a few about that bolt

At Approximately 1:50 in the video el dudearino talks about it. Work very carefully with that bolt - many lose it - work during the day when the sun is out and you aren't stressed for time.

The blend door will work with (2) bolts - but just sayin'

Welcome to the forum, report back and good luck!

Take some pics of your repair for posterity

This is all excellent advice, I appreciate your time to walk me through it! I will definitely take some pics of the repair and let you know the outcome!
Thank you so much!

 

[C420sailor]

That switch brings me back. My dad had an unmarked ‘take home’ crown vic when I was a kid. Had a unitrol siren in it and a pair of flashing grille lights.

 

[DR98FL]

Econo blend door option

 

[Mbrooks420]

Fix the blend door by cutting the access panel as shown in the video. Those switches can be pulled by unscrewing the lock down nut, then you can push them through.