Knowledgeable Ford person question?

[colliehauler]

On my heater control the temp control blows hot even when you turn it to cool on the temp control.

The truck is a 2000 F-250 Superduty.

I did not see a control device on the heater hose, so I assume it is internal by the heater core.

Any ideas?

[Wes_Tausend]

colliehauler wrote:

Gdetrailer wrote:

#40Fan wrote:
Can you change from vent to floor to defrost? Your system is all vacuum controlled.

Blend door is not vacuum operated..

It is an electric SERVO MOTOR.

If you notice item #4 does not have a vacuum line routed to it.

Thanks everyone for the replies, I think it is the servo that operates the blend door. It has started working again on its own.

I'm wondering if it would be a good idea to add a water shut off valve to the heater core?

Sounds like a pain to replace the servo motor.

It switches from floor-vent- defrost without issue.

The A/C worked fine last time I used it before this problem.

Like I said earlier it seems to be working again, I can get cool air out of the vent again.

I think there is a lot of very knowledgeable people on this forum and again I would like to say thank you.

I would also like to take this opportunity to especially thank Gdetrailer for his insights. He's been here a long time and often offers valuable tech info. He may seem a bit blunt at times, and I don't always agree with him, but I highly respect his tech savvy and enjoy reading his posts. In this case, between #40Fan's link, and Gdetrailer's talent for detail, I learned quite a bit about my own year 2000 Ford trucks. Three cheers for these guys, and a tip o' the hat for others that contributed too.

And good luck to you, colliehauler, on going on to solve the problem permanently. It sounds like a good idea to me, to add a water shut off valve to the heater core. Less hassle than tearing the truck apart and you shouldn't have to reset the valve often, more-or-less seasonally only.

As an aside, even the truck forums are dead wrong on occasion. I had a steering problem with my "pre-owned" F-250, and the only guy on the whole net to ever solve it was immediately dissed by the rest of the forum members and never posted again. It turns out the previously installed new ball-joints were too tight and most local alignment shops across the country had no idea, had never heard of it. Most operators would be first inclined to think the steering was somehow too loose, but it was exactly the opposite problem upon close inspection, and is not uncommon on Dodge 4x4 either. Coming from constant steering correction, it steers like new now, no fancy aftermarket suspension gimmics needed.

Wes
...

[colliehauler]

Gdetrailer wrote:

#40Fan wrote:
Can you change from vent to floor to defrost? Your system is all vacuum controlled.

Blend door is not vacuum operated..

It is an electric SERVO MOTOR.

If you notice item #4 does not have a vacuum line routed to it.

Thanks everyone for the replies, I think it is the servo that operates the blend door. It has started working again on its own.

I'm wondering if it would be a good idea to add a water shut off valve to the heater core?

Sounds like a pain to replace the servo motor.

It switches from floor-vent- defrost without issue.

The A/C worked fine last time I used it before this problem.

Like I said earlier it seems to be working again, I can get cool air out of the vent again.

I think there is a lot of very knowledgeable people on this forum and again I would like to say thank you.

[shum02]

Gdetrailer wrote:
Bird Freak writes

Either Ford Truck Enthusiasts or The Diesel Stop may have MUCH better well informed information about how to troubleshoot and repair this problem than this forum from some of the off the wall answers I have been reading.

I've been having a good giggle :B

[Wes_Tausend]

...

Regarding the heat available during cooling, the system design allows very moderate cooling on cool rainy days with some heat applied to keep full cold at bay. This accomplishes excess humidity removal while not over cooling on an already cool day. I like this dehumidifying feature to furnish warm, dry cabin air and wish my home allowed both systems to run concurrently. But, yes, Ford's design may also complicate the mechanism and servicing thereof.

One other point is that, except for Max-Air, cabin air is drawn from outside through the outer vent in front of the windshield. When ambient outside vent air is preferred right after being parked hot for a period, the engine heat has heat-soaked the firewall which contains the outer vent passages, so the first blast is quite warm. By running the AC for a short while, the vent-way finally cools enough so that outside air feels like the expected normal outside temp, and the AC can be shut back off to vent-only.

Wes
...

[Gdetrailer]

Bird Freak writes “I know my 04 has a valve under the hood on the evaporator case.”

Correct.

I had a ’97 which indeed had a vacuum operated valve on the heater core circuit, doesn’t mean EVERY vehicle Ford built has one.

Our 2003 F250 DOES NOT.

Our 2006 F250 DOES have the valve, so somewhere between ’04-’06 MYs Ford put the valve back in.. But even though Ford did put the valve back on it doesn’t mean it cuts off the hot water all the time.. Our ’06 the hot water valve closes ONLY on MAX A/C.. All other positions including normal A/C the valve is open allowing hot water to run through the core. And even then for whatever reason Ford decided when you use Max A/C position they would disable the blend door control to cold position.. Makes the Max A/C setting useless for anything other than fast cooldown..

Our 2003 has the most pathetic and lethargic A/C you could get and for those model years which do not have the valve it was a very popular “mod” to add the valve. I never bothered to make that mod but that A/C took easily 1/2hr of driving before the cab temps were reasonable in 90+ outside temps.

I highly suspect the OPs issue is most likely the blend door servo motor.. It is stuck or broken in heat position.

This part was not designed to be changed with the dash in place nor with the heat-A/C box in place.. Makes for a real challenge to remove in place.. It can be done but it will not be easy.. That is why I suggested to check the A/C clutch FIRST to ensure it is engaging.

With the setup Ford has it USES the A/C AND heater core to blend the air temp, if A/C is not working the result is hot air even when you set the control to cool and no A/C.. It is odd, but that IS one of the side effects I found out when the clutch on my 2003 started acting up..

Either Ford Truck Enthusiasts or The Diesel Stop may have MUCH better well informed information about how to troubleshoot and repair this problem than this forum from some of the off the wall answers I have been reading.

[Gdetrailer]

#40Fan wrote:
Can you change from vent to floor to defrost? Your system is all vacuum controlled.

Blend door is not vacuum operated..

It is an electric SERVO MOTOR.

If you notice item #4 does not have a vacuum line routed to it.

[_40Fan]

Can you change from vent to floor to defrost? Your system is all vacuum controlled.

[Fast_Mopar]

MegaCab_PL wrote:
Most likely it's a blend door, or the blend door actuator.

Common issue on my 06 Explorer as well.
In my case the passenger side blows cool, the left side is warmer.

That happened to my Ford Windstar van. I was told at the time that it was a very common issue.

[MegaCab_PL]

Most likely it's a blend door, or the blend door actuator.

Common issue on my 06 Explorer as well.
In my case the passenger side blows cool, the left side is warmer.

[RJCorazza]

Go over to Ford Truck Enthusiasts web site and do a search. My 97 (F150) had a similar symptom that ended up being a blend door with stripped gears. On my truck (may be apples to oranges) the repair would have involved removing the whole dash at $800 + by dealer. I bought an after market door in 2 pieces with detailed instructions on how to access the door by cutting into the inside of the glove box. About a hour and like $120. This was 5 years ago, and while reading up on the topic many late 90's and early 2000's Fords had this problem (cars and trucks). YMMV.

[Golden_HVAC]

Hi,

I have taken apart some heater boxes, and found that sometimes (like in this case) the hot water goes through the heater core all the time, and you adjust the 'hot - cooler' control to swing a damper from fully open to just the cold air from the cooling coil, or to all the air going through the hot water coil, or something in between.

I have found that a ball valve inline with the heater core water lines is handy to keep the air cooler coming out of the A/C vents! The 'insulation' between the hot water coil and cool airstream is only about 1/8" thick plastic door!

Fred.

[Bird_Freak]

Gdetrailer wrote:

2112 wrote:

Bird Freak wrote:
Check under your hood and see if the vacuum tube has come off the heater control valve. If it will not shut the hot water off it will blow hot. Mine did that.

My '97 did this. The vacuum line was brittle and broke. It fails hot.

OP has a 2000, sometime in the early 2000 models Ford OMITTED the vacuum shutoff valve. My 2003 F250 DOES NOT HAVE any hot water shutoff so the core is always hot.

The OP has one of two known issues, the easy one to fix is the A/C compressor clutch, the clutch material has worn down and is not engaging the compressor.. And YES, when the compressor is not engaging you WILL get HOT air..

To fix that you pull the compressor clutch and remove a shim to re-establish the correct air gap for the clutch.

The worst case issue is the "blend" door motor which blends the hot and cool air has failed.. Changing the blend door motor is a real bear from what I understand..

Do a search for a/c compressor clutch repair, should be able to find that info and do a search for Ford blend door motor should be able to find details on that repair..

I know my 04 has a valve under the hood on the evaporator case.

[Gdetrailer]

2112 wrote:

Bird Freak wrote:
Check under your hood and see if the vacuum tube has come off the heater control valve. If it will not shut the hot water off it will blow hot. Mine did that.

My '97 did this. The vacuum line was brittle and broke. It fails hot.

OP has a 2000, sometime in the early 2000 models Ford OMITTED the vacuum shutoff valve. My 2003 F250 DOES NOT HAVE any hot water shutoff so the core is always hot.

The OP has one of two known issues, the easy one to fix is the A/C compressor clutch, the clutch material has worn down and is not engaging the compressor.. And YES, when the compressor is not engaging you WILL get HOT air..

To fix that you pull the compressor clutch and remove a shim to re-establish the correct air gap for the clutch.

The worst case issue is the "blend" door motor which blends the hot and cool air has failed.. Changing the blend door motor is a real bear from what I understand..

Do a search for a/c compressor clutch repair, should be able to find that info and do a search for Ford blend door motor should be able to find details on that repair..

[marcsbigfoot20b]

colliehauler wrote:
On my heater control the temp control blows hot even when you turn it to cool on the temp control.

The truck is a 2000 F-250 Superduty.

I did not see a control device on the heater hose, so I assume it is internal by the heater core.

Any ideas?

If it is a diesel like mine, there is no heater control valve.
The fresh air comes from the vents at the bottom of the windshield.
Try this thread... AC mod