Heater Control Valve Question
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Fleet Mechanic
Joined: Oct 2010
Posts: 1,407
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From: Milwaukee, WI
Heater Control Valve Question
YES, I know it's summer but, still...
While diagnosing a problem with my rear AC not working, I pulled the rear plenum apart. I noticed the rear heater coil was really hot even though I did not turn the heat on at all that day.
I suspect a bad heater control valve. The one that stops hot coolant from going to the core when the AC is on. I have manual temp controls so I assumen it is vacuum controlled. Alldata does not give me a loction or vacuum routing specs for the valve so I am asking here.
1) Where do I find the heater control valve? Anyone have a picture?
2) Does it shut off the coolant to both the front and rear heater cores or just the front?
Thanks!
While diagnosing a problem with my rear AC not working, I pulled the rear plenum apart. I noticed the rear heater coil was really hot even though I did not turn the heat on at all that day.
I suspect a bad heater control valve. The one that stops hot coolant from going to the core when the AC is on. I have manual temp controls so I assumen it is vacuum controlled. Alldata does not give me a loction or vacuum routing specs for the valve so I am asking here.
1) Where do I find the heater control valve? Anyone have a picture?
2) Does it shut off the coolant to both the front and rear heater cores or just the front?
Thanks!
Last edited by jasonodsky; Jul 11, 2011 at 03:53 PM. Reason: add header
Lead Driver
Joined: Nov 2007
Posts: 5,139
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If you have a heater control valve, you should be able to find it fairly easily in the engine compartment. Trace your heater hoses, and look for the valve. The vacuum line may have come off of it, causing your hot coil issue. One valve should shut off the flow from both front, and rear coils.
My 04 is a diesel and the valve is on the passenger side of the engine compartment, back towards the firewall, with a small grey vacuum line attached to it.
My 04 is a diesel and the valve is on the passenger side of the engine compartment, back towards the firewall, with a small grey vacuum line attached to it.
FTE Chapter Leader
Joined: Nov 2010
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From: N. IL
Jason, check on the passenger side. I used this to fix my 'no heat' situation, but I never did check the rear heat (just camping gear back there and it doesn't complain)
Disconnect the hoses gently else get coolant everywhere and down those cops!
Sean
While you're in there scraping knuckles clean up the PCV - (pic 3 stinkin' coolant everywhere.
)
Disconnect the hoses gently else get coolant everywhere and down those cops!
Sean
While you're in there scraping knuckles clean up the PCV - (pic 3 stinkin' coolant everywhere.
)
Lead Driver
Joined: Nov 2007
Posts: 5,139
Likes: 209
Jason, check on the passenger side. I used this to fix my 'no heat' situation, but I never did check the rear heat (just camping gear back there and it doesn't complain)
Disconnect the hoses gently else get coolant everywhere and down those cops!
Sean
While you're in there scraping knuckles clean up the PCV - (pic 3 stinkin' coolant everywhere.)
Disconnect the hoses gently else get coolant everywhere and down those cops!
Sean
While you're in there scraping knuckles clean up the PCV - (pic 3 stinkin' coolant everywhere.
)
FTE Chapter Leader
Joined: Nov 2010
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From: N. IL
Veggies at work, but prefer camping.
Live in Camarillo, check Trey's map (So Calif Chapter).
Lead Driver
Joined: Nov 2007
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I was thinking "Where in So C"......
Nevermind.
Great post and pics
Nevermind.
Great post and pics
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Fleet Mechanic
Joined: Oct 2010
Posts: 1,407
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From: Milwaukee, WI
Thanks Sean and william_04_x. It was really obvious to find once I looked . My '04 has the electrically heated PCV so there is no heater line going to it. I just replaced the PCV last week.
The '04 in line valve is still vacuum acuated but there is actually an arm and diaphram I can watch actuate when I change from AC to heat. I moved it a couple of times manually and then tested it from the cabin switch. It moved as expected but since I disturbed it before checking it from the cabin, it could have been stuck.
I'll do some testing and check the temp of the line behind the valve to see if it is getting hot and possibly leaking past the valve. I'll also clamp the hose and see if that changes things. I'll try to post a pic of the '04 version of the valve later today.
. My '04 has the electrically heated PCV so there is no heater line going to it. I just replaced the PCV last week.The '04 in line valve is still vacuum acuated but there is actually an arm and diaphram I can watch actuate when I change from AC to heat. I moved it a couple of times manually and then tested it from the cabin switch. It moved as expected but since I disturbed it before checking it from the cabin, it could have been stuck.
I'll do some testing and check the temp of the line behind the valve to see if it is getting hot and possibly leaking past the valve. I'll also clamp the hose and see if that changes things. I'll try to post a pic of the '04 version of the valve later today.
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Jason, check on the passenger side. I used this to fix my 'no heat' situation, but I never did check the rear heat (just camping gear back there and it doesn't complain)
Disconnect the hoses gently else get coolant everywhere and down those cops!
Sean
While you're in there scraping knuckles clean up the PCV - (pic 3 stinkin' coolant everywhere.)
Disconnect the hoses gently else get coolant everywhere and down those cops!
Sean
While you're in there scraping knuckles clean up the PCV - (pic 3 stinkin' coolant everywhere.
)
FTE Chapter Leader
Joined: Nov 2010
Posts: 30,595
Likes: 1,236
From: N. IL
My guess is the bottom hose goes to the rear heater in the Ex. The upper left
one goes to the front passenger heater. I've never investigated this though. The one valve controls both heaters.
I was replacing this valve yearly with cheap parts; since I used a Ford part, haven't had any issue for a couple of years.
one goes to the front passenger heater. I've never investigated this though. The one valve controls both heaters.
I was replacing this valve yearly with cheap parts; since I used a Ford part, haven't had any issue for a couple of years.
New User
Joined: Jul 2016
Posts: 7
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My guess is the bottom hose goes to the rear heater in the Ex. The upper left
one goes to the front passenger heater. I've never investigated this though. The one valve controls both heaters.
I was replacing this valve yearly with cheap parts; since I used a Ford part, haven't had any issue for a couple of years.
one goes to the front passenger heater. I've never investigated this though. The one valve controls both heaters.
I was replacing this valve yearly with cheap parts; since I used a Ford part, haven't had any issue for a couple of years.
Elder User
Joined: May 2014
Posts: 547
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From: Southern California
I went/am going through this very thing. It drives me crazy that the vehicle just doesn't seem get that cool. Then the other night we were driving home at about dusk, it was still about 95 outside and I noticed the ac seemed cooler. I think we have so much surface area that the sun has a huge advantage. Now I am thinking about ceramic window tint again.
FTE Chapter Leader
Joined: Nov 2010
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From: N. IL
https://www.ford-trucks.com/forums/1...l#post15048442
Give your fan clutch a check, if it's not working on a hot day, that a/c will never be cold.
Give your fan clutch a check, if it's not working on a hot day, that a/c will never be cold.
Cargo Master
Joined: Mar 2011
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From: North Texas
The heater control valve only gets vac when on "MAX A/C" any other settings it opens up. My black truck in the Texas heat takes quite a while to cool down if I don't crack the windows while parked. After a few miles on the freeway though, its blowing nice cold air. I think its just the size of the greenhouse we drive around.
New User
Joined: Jul 2016
Posts: 7
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I went/am going through this very thing. It drives me crazy that the vehicle just doesn't seem get that cool. Then the other night we were driving home at about dusk, it was still about 95 outside and I noticed the ac seemed cooler. I think we have so much surface area that the sun has a huge advantage. Now I am thinking about ceramic window tint again.