Heater Problem
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Junior User
Joined: Oct 2008
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From: West Des Moines, Iowa
Heater Problem
Hi there new here dont know if its been posted but its cold outside so i need help. I was just given a 1975 ford f150 ranger with the 390. It has a non functioning heater. The guy who gave it to me told me it was the blower motor but i cant be sure. Nothing works when you turn any dials so i cant even be sure power is going to it. Could it be the heater core, im just not sure. Any help would be great.
Ben
Ben
Ford Parts Specialist
Joined: Nov 2006
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From: Simi Valley, CA
Hi there new here dont know if its been posted but its cold outside so i need help. I was just given a 1975 ford f150 ranger with the 390. It has a non functioning heater. The guy who gave it to me told me it was the blower motor but i cant be sure. Nothing works when you turn any dials so i cant even be sure power is going to it. Could it be the heater core, im just not sure. Any help would be great.
Ben
Ben
Does the truck also have factory Air Conditioning? With factory A/C, the control panel on the dash for the heater also operates the A/C, and is so marked.
I need to know this because when A/C is present, the truck has two additional features that affect how the heater operates.
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Junior User
Joined: Oct 2008
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From: West Des Moines, Iowa
i am almost positive it has air but most of it from the motor has been removed so i dont care about rechargeing or keeping the air conditioning. I just need heat, getting cold and i dotn have anything to defrost the windshield.
Ben
Ben
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From: Northeast LA
The heater core doesn't do anything but have water running through it. So if you have hoses running from the engine to the heater core and the core's not leaking that part should be fine. I don't know when they started putting the big black boxes under the hood if it has factory air but my 77 does. That'd be any easy way to tell if it had factory air at one time. I took all my factory AC stuff out but I kept the heater just for the defrost.
Ford Parts Specialist
Joined: Nov 2006
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From: Simi Valley, CA
If the A/C has been removed, why would someone go thru the trouble of changing that control panel?
When the truck has A/C, it also has a heater temperature control (water) valve on the engine, and a multi function valve attached to the back of the control panel.
If either fails, the heater will not work.
The vacuum controlled water valve is notorious for failing.
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Junior User
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From: West Des Moines, Iowa
heater will not work as in nothing comes out at all. Becaust i cant get hot or cold to come out i turn it on and nothing happens. Buy the way it was a factory ac truck.
Ben
Ben
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
Under the hood, spliced into the inlet heater hose to heater core is this:
D4AZ18495A .. Heater Temperature Control (Water) Valve-Vacuum Operated (Motorcraft YG136)
When you move the lever on the control panel, vacuum opens this valve up to allow hot water to flow to the heater core. It's been a POS since the 1970's and is notorious for failing.
Every parts store (and Ford dealers-it's still available) should have it, as it fits a large number of different cars/trucks from 1971 thru the 1990's.
Ford MSRP: $28.72 / FTEpartsguy.com price: $17.23
---------------------------------------------------
This is another part that might be causing the problem.
The multi function valve, D5TZ19B888A (Motorcraft YH285) mounts to the backside of the heater control panel and operates the blend door motors.
When you move the lever on the control panel, the valve opens one blend door, and closes another.
When this valve fails, none of the blend doors will open. All the vacuum lines from the heater connect to this valve.
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Posting Guru
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From: Northeast LA
But Bill those are vaccum switches for the temp aren't they? Do those have any effect at all on the fan coming on? It sounds to me like when he moves the fan speed switch nothing happens, like either the blower motor is not getting power or it's broke and seized up? Before I replaced my heater core I had it bypassed, I could still hit the fan speed and it'd blow air out the vents. Thats what I get out of his question I could be wrong. I don't think his total problem is no heat out the vents its' no movement of air at all from the vents.
Thanks,
Thanks,
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Joined: Sep 2008
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From: Pennsylvania
I'm no expert, but I do have heater problems too, and I've done some investigation. Are you sure that your heater fan/blower motor is plugged into a power source? If there is a wire connected, check to see it's not cut anywhere. If it's not cut, I'd take a guess that your fan/blower motor is broken, stuck, or missing. The guy who gave you the truck may have just been right.
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Junior User
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From: West Des Moines, Iowa
Ok for those who arent following or are not sure what im talking about ill explain again. The guy who i bought the truck from said the heater didnt work. Didnt work when he bought it and it doesnt work 3 years latter. He never looked into it he just drove it to haul around stuff in the summer. You can turn the any position, vent, ac, defrost nothing works. I can hear alittle air whisp out like that vacume line kicked something over but the motor doesnt work. No air comes through the vents hot or cold, So its either a power problem, or the whole thing needs replaced.
Postmaster
Joined: Aug 2005
Posts: 2,760
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From: Gadsden Purchase
All these systems are separate in their function. :)
Feel the heater core's hoses for hot water flowing.
Look to see if the vacuum actuated heater-core-water control is moving.
Mine quit right after it went out of warranty they wanted ~$40 for a new
one and it hasn't had a vacuum actuated heater-core control since! :)
Actually I "fixed" the original and it last a couple months and froze closed
again before I gave up on the rusty iron piece of crap. ;)
http://www.panix.com/~alvinj/file12/bypass.jpg
The fan motor is controlled by an "accessory relay".
That too was a piece of Ford crap. :/ (along with their horn relay)
Even an Eklin brand "Ford accessory relay" couldn't handle the current for long.
(under-rated requirements from Ford?)
Bought a Eklin brand "Ford window relay" and it's been working fine since. :)
Anyway you need to understand the separate systems, then you will figure
out which of them ain't working right (maybe none of them! ;) and the fix
will be easy. :)
"it's easy when you know how" -cowboy buddy of mine
Alvin in AZ
Feel the heater core's hoses for hot water flowing.
Look to see if the vacuum actuated heater-core-water control is moving.
Mine quit right after it went out of warranty they wanted ~$40 for a new
one and it hasn't had a vacuum actuated heater-core control since! :)
Actually I "fixed" the original and it last a couple months and froze closed
again before I gave up on the rusty iron piece of crap. ;)
http://www.panix.com/~alvinj/file12/bypass.jpg
The fan motor is controlled by an "accessory relay".
That too was a piece of Ford crap. :/ (along with their horn relay)
Even an Eklin brand "Ford accessory relay" couldn't handle the current for long.
(under-rated requirements from Ford?)
Bought a Eklin brand "Ford window relay" and it's been working fine since. :)
Anyway you need to understand the separate systems, then you will figure
out which of them ain't working right (maybe none of them! ;) and the fix
will be easy. :)
"it's easy when you know how" -cowboy buddy of mine
Alvin in AZ
Posting Guru
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From: Northeast LA
And knowing is half the battle! - G.I. Joe
I know that's not useful but I had to throw it in. Good luck tracking down the problem. Then look forward to the next one cause the gremlins just make their way around the truck from part to part!
I know that's not useful but I had to throw it in. Good luck tracking down the problem. Then look forward to the next one cause the gremlins just make their way around the truck from part to part!
Postmaster
Joined: Aug 2005
Posts: 2,760
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From: Gadsden Purchase
...but compared to an old air cooled VW tho! ;)
These old suckers are nearly trouble free. :)
Good thing for me it's ok to throw-in stuff that ain't useful.
I wouldn't get to post at all. :/
---> drfelgood5 asked:
"Where is that relay located at on the truck."
On mine it was friggin hidden. :(
No kidding. :/
It was screwed to the firewall.
I used to take out the glove box and reach in with a 1/4" drive extension
with a knuckle-socket on it to get to mine. It was a pain in the neck.
A good one for "warranty work" you suppose? ;)
I moved that sucker! :)
Alvin in AZ
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Junior User
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From: West Des Moines, Iowa
My DD is a subaru so i know all about gremlins. Is there an easier way to test this, i suspost if i half to change the fan i need to tear out half the dash anyways to get to the thing, i just dont know if i have time to do all of that.