I just got my Marquis 2 weeks ago and the problem im having is i have no heat control. So i have no control of the temp blend door. i went under the dash and unplugged the vac line to the blend door and i have great heat, so i have the line plugged right now. I would like to be able to control the heat and ac in the car. I read a few posts and i understand how the auto climate control works but where do i start? thanks!
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1985 Grand Marquis heat problems, Full cold no heat!
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The temperature sensor above the glovebox is bad. Pull the dash pad off and you'll find a blue thing under there with 2 vacuum hoses, a crinkle hose and a cable hooked to it. Replace that and the system ought to work normally again.
The only other thing its reallyl ikely to be is the cable is broken or unhooked. Pull the dash pad and watch the cable on the sensor. If it doesn't move with the temperature lever, the cable has a problem. If it moves, its the sensor.86 Lincoln Town Car (Galactica).
5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley
91 Lincoln Mark VII LSC grandpa spec white and cranberry
1984 Lincoln Continental TurboDiesel - rolls coal
Originally posted by phayzer5
I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers
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Originally posted by gadget73 View PostThe temperature sensor above the glovebox is bad. Pull the dash pad off and you'll find a blue thing under there with 2 vacuum hoses, a crinkle hose and a cable hooked to it. Replace that and the system ought to work normally again.
The only other thing its reallyl ikely to be is the cable is broken or unhooked. Pull the dash pad and watch the cable on the sensor. If it doesn't move with the temperature lever, the cable has a problem. If it moves, its the sensor.1985 Crown Victoria Tudor
1990 Mustang LX 5.0 conv
1996 F250 Power Stroke
2004 Mustang GT conv
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$15? I think you are looking at the wrong one...
Motorcraft YH409 is what you need. Rock Auto has it for about $70.
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)
Originally posted by gadget73... and it should all work like magic and unicorns and stuff.Originally posted by dmccaigOverhead, some poor bastards are flying in airplanes.
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yeah was gonna say if they sell for 15 bucks at Napa I'm buying a case of the things.86 Lincoln Town Car (Galactica).
5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley
91 Lincoln Mark VII LSC grandpa spec white and cranberry
1984 Lincoln Continental TurboDiesel - rolls coal
Originally posted by phayzer5
I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers
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I bought a $5 small engine fuel petcock to fix mine, I haven't tried it yet but hopefully I can plumb it into the vacuum hose and set it halfway for 'medium' heat, lolPete ::::>>> resident LED addict and CFI defector LED bulb replacements
'LTD HPP' 85 Vic (my rusty baby) '06 Honda Reflex 250cc 'Baileys' 91 Vic (faded cream puff) ClifFord 'ODB' 88 P72 (SOLD) '77 LTDII (RIP)
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85HPP's most noteworthy mods: CFI to SEFI conversion w/HO upperstuff headers & flowmasters P71 airbox Towncar seats LED dash light-show center console w/5 gauge package LED 3rd brake light 3G alternator mini starter washer/coolant bottle upgrade Towncar power trunk pull underhood fuse/relay box 16" HPP wheels - police swaybars w/poly rubbers - budget Alpine driven 10 speaker stereo
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Either not the problem or you'll have to spring for a new Ford part!
"Hope and dignity are two things NO ONE can take away from you - you have to relinquish them on your own" Miamibob
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They get bad with time. Basically the internal construction is two holes with a rubber diaphragm thats attatched to a metal plate between them. As the temperature changes, that plate warps and allows more or less vacuum to pass between the ports. Adjustment is by a tiny spring in the middle of the plate that puts more or less tension on it. When the rubber petrifies, it doesn't seal and you get lots of hot. When the spring or the plate loses its springiness, you get no hot. Unfortunately these things simply do not age well. Its not exactly the most reliable system on earth, though mercifully its really easy to fix. Or at least it is so long as we can get the parts to fix it.
One of these days I wouldn't mind figuring out an electronic conversion for this thing that retains the original vacuum motor on the plenum, but replaces the mechanical regulator with something like the EVR solenoid, and drive it with some sort of circuit that incorporates a temperature sensor and a varible resistor to connect the slidey control cable to. Done right, it ought to replicate the original function without having to actually change anything on the car. Just feed it power and hook up the lines. I'll put that on my list of things to do right after I invent a time machine so I actually have time to do this crap.Last edited by gadget73; 11-17-2011, 07:01 PM.86 Lincoln Town Car (Galactica).
5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley
91 Lincoln Mark VII LSC grandpa spec white and cranberry
1984 Lincoln Continental TurboDiesel - rolls coal
Originally posted by phayzer5
I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers
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EVR solenoid works on PWM doesn't it (pretty much open or closed and pulsed to make intermediate adjustments)?
if that's the case... a pair of LM34/LM35 (depending on if you want to program in F or C) to read cabin and blower temps and a uC to an SSR for driving the solenoid would work like a champ. I would think an AT-tiny (or other low pin count uC) should be perfect for such a thing. The perf board would be real small and you would just need a 5v DC-DC circuit to drive the uC and the regular voltage to go through the SSR. The programming would be pretty simple as it would just need to be a simple comparator and set limits for the full on and full off and PWM settings for the in-between stuff. Probably have a total parts cost for the electronics near $20 or less.
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)
Originally posted by gadget73... and it should all work like magic and unicorns and stuff.Originally posted by dmccaigOverhead, some poor bastards are flying in airplanes.
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yeah the EVR is PWM, though its 12v so probably couldn't run specifically an EVR solenoid if it ran off a 5vdc output. The other thing is, I believe its limited to 8 inches vacuum max, though I'm not positive if thats due to internal construction of the EVR or if that just happens to be what the computer's output range is limited to. Then again, 8 inHg might be enough to drive the blend door fully cold. Easy enough to check, but not tonight.
I also don't know what sort of frequency range you'd need to vary to get that EVR to do what you want. digital electronics are flatly not my thing. I get analog circuits, but digital is incomprehensible.86 Lincoln Town Car (Galactica).
5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley
91 Lincoln Mark VII LSC grandpa spec white and cranberry
1984 Lincoln Continental TurboDiesel - rolls coal
Originally posted by phayzer5
I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers
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the 12V to the EVR solenoid would be supplied by the solid state relay (SSR) that is triggered by the 5V microcontroller. all the rest is just tedious maths and testing as far as the programming goes.
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)
Originally posted by gadget73... and it should all work like magic and unicorns and stuff.Originally posted by dmccaigOverhead, some poor bastards are flying in airplanes.
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