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View Full Version : no heat, no floor setting



89LincolnTWNcar
04-16-2006, 04:51 PM
Hey all my car has no heat at all, I can move the thermostat to 85 and it won't get hot even after hours of driving, and no air comes out at all on floor setting. The AC works awesome and blows cold, but will again not blow hot. I cleaned the terminals on that sensor that goes inline on that one coolant hose to the core, nothing got fixed. any ideas??

Grand Marquis GT
04-16-2006, 04:54 PM
You running a thermostat, by chance?

gadget73
04-16-2006, 05:30 PM
The blower lockout switch is probably shot. Unplug the electrical connector from that in-line doodad on the heater hose and jumper it, and you should get air blowing on the floor setting.The no air on floor 99% of the time is that switch under the hood. I'd suggest a Motorcraft replacement. The aftermarket ones are apparently garbage. Both Scott and I had one explode for no obvious reason. Mine popped today on the way to the store for something else, and I replaced it with a simple plastic hose connector. I'm done with that stupid system. The vacuum portion of it leaked and caused my whole climate controls to go nuts, the electrical wiring rubbed through and burt out the ignition switch, and a fuse link under the hood, and now it exploded causing the motor to overheat. Not dealing with that stupid thing any more.

Whether or not its actually hot would be a different issue. Can you get hot air with the controls on vent? If not, the blend door might be jammed or the ATC sensor shot. To check if its the ATC sensor, look on the passenger side under the glovebox. There is a metal canister with a clear vac line connected to it. Unplug that, and it will force the system to full hot. If that won't force it to hot, the door is probably jammed. See if you can tell where the vac motor attaches to the door and try and move it manually. Usually they don't jam, just the sensor fails and it flips randomly from hot to cold, it won't heat, or does something else wierd like that.

89LincolnTWNcar
04-27-2006, 06:45 PM
im pretty sure its the door, I can hear it close after I shut off the car and it takes forever to close. Also when I put the selector to defrost it blows out the floor vents a little bit, like its not moving all the way.

85crownHPP
04-28-2006, 01:45 AM
if the fan doesnt blow when its in the floor setting, its bound to be the heater hose sensor/switch like gadget said.
Im guessing your heat isnt an issue now that its warming up - but the temporary fix he posted made my heat work like hell fire! But this temp fix makes it all or nothing. better than no heat though...

gadget73
04-28-2006, 02:06 AM
The system holds vacuum with the engine shut off, so it should take a while for it to close. As it bleeds down, it'll sloooooowly creep closed. That soup can on the fender is the reservoir for the ATC system, and there is a one-way valve so the ATC stuff holds vacuum even when the engine has none. If you take that and the soup can away, every time you hit the gas, the system will totally freak out and flip modes and stuff on you. My can was rotted out, and it had a leak at the blower lockout, made the whole thing retarded. It would go from cold AC to hot defrost, which is the default setting when it looses vacuum.

I still bet the blower problem on floor is the blower lockout, and the temperature issue is the sensor above the glovebox. The climate controls in these thigns are really flaky to begin with, and it doesn't take a whole lot to make it screw up. That temperature modulated vacuum valve design is a mess. It would probably work fine if you designed an electronic vacuum regulator for it instead of a mechanical. The way it works is it actually has a metal diapgram in there that warps with temperature and causes a vacuum leak. Not exactly precise stuff. Problem is, that metal diaphram takes a set over time and won't warp anymore. The temperature adjustment is provided by pulling on the diaphram with a spring, which makes it more or less inclined to warp. That spring also stretches and won't pull as much so it just stays on cold.

p71towny
04-28-2006, 03:02 AM
I just jumped mine under the dash and used a 1 way check valve for vaccuum to keep my system from bleeding down. Works perfect.

gadget73
04-28-2006, 10:18 PM
Doesn't that give you full heat all the time tho? Us people with AC who dislike roasting in the summer don't want the heat cranking all the time.

p71towny
05-03-2006, 01:26 AM
Hells no, I wouldn't do it if it fucked up my normal functions. A/C works fine and so does everything else.