Heater Control ??

[89ltcsignitureseries]

My heater somtimes work when I move the lever all the way to the end (89 degree) somtimes is just blow cold air.

I have heard that Linclon are known for heater problems, is that true for the older one's (1989). Should it be replaced or fix. Appricate any feed backs.

 

[Redwingvksm]

ALL Fords are known for heatercore failure.

If you do NOT have a leak - just flush it out. 2 coolant hoses that go into the firewall - just run a shot of water/air/water/air/etc...through EACH of the tubes (So you do a reverse flush too) on it - and try it. If that doesn't fix your heat prob and you have NO leaks - your blend door is stuck (Vacuum not high enough/baffold is clogged/etc...)

 

[Frat-man-du]

Blend door was the issue on my 90 TC, heater control Valve on my 85 Thunderbird and a vaccum leak on my 92 Marque... I guess all F/L/M do have bad heaters. Sux when defrost wont work.

 

[red91sit]

My heater somtimes work when I move the lever all the way to the end (89 degree) somtimes is just blow cold air.

I have heard that Linclon are known for heater problems, is that true for the older one's (1989). Should it be replaced or fix. Appricate any feed backs.

By looking up from the passengers floor you can seee hte blend door and if it's working. If it is, it's probobly this other peice that's gone bad, open up your glove box, there should be a clear tube connected to a golden colored thinger. If you disconnect and plug this hose, YOu'll have full heat, IF you want to fix it so you have a normally operating system, I believe it needs to be replaced.

 

[lokhankin]

Heater core or control unit?

I'm also a recent LTC'89 owner without heat. kind of without.
Car I have - was seatting for years and now - after oil, thermostat and radiator changes engine runs fine. Car dowsn't need to be warmed up after sitting overnight - as engine doesn't stall (I still let it run idle few min).

Besides shaking during breaking and feeling that transmission is trying to shift up or down in range between 40-60 mph - my major problem is heating.
Heat blows inside only when car is under heavy load going uphill or it just warmed up in a very cold day.
When coasting or going downhill - it's just outside air tempreture blowing through vents.
Also - during those periods, when hot air is produced and lever is on VENT - actual airflow goes into windshield, then in few min it gets into front (chest level) vents. However - if FLOOR selected - no air goes anywhere. Thankfully - when windshield fogged directing air to WINDSHIELD does do the job (still with cold air).

All these symptoms make me think that it's rather heater/ac control assembly issue than heater core as there are no any traces of coolant from under glove compartment.

Thanks a lot.
--Vas

 

[BMR1580]

Hey Everybody. I am also a new 89 TC owner and I have had or am having the exact same issues as lokhankin, and I MEAN exact. As far as where the transmission tries to shift, remember the car was designed when the national speed limit was 55. I try to keep the car in Drive rather than Overdrive whenever I'm not going to be cruising long over 50 or so. When I will be cruising, I just try to control where it shifts with the gas pedal. It's a pretty deep gas pedal.

I solved my braking shakes by changing out the upper control arm bushings on both sides, and since the arms were off, I changed the ball joints, too. I discovered the horrid state of the bushing while changing the obviously blown shocks out. All of that did a good job of tightening up the steering, as well. The car handles beautifully now.

As with you, my major problem is now the heating. As far as I can tell, the blend door is working exactly as it should, I didn't have a problem with hot air getting in during the summer, that A/C was a champ. When the air is hot, it is always coming from the correct place, though the fan shuts off instantly when I set it to floor and I can only feel tiny amounts of air coming through when I am moving. If I turn on the A/C and set the thermostat on heat, it will warm up for a few minutes and then it will start blowing pure, cold air and the compressor turns on and off a lot. It's getting cold outside guys, can anyone help?

Thanks, B

 

[abe_lincoln78]

Hey, guys. Its most likely not the blend door. You will find under the dash pad a thermostatic valve that controls how much vacuum goes to the blend door. The heat control slider on the '80 - '89 towncar actually connects directly to it. You can get this part off any TC from these years as well as any crown vic or grand marquis with the automatic temperature control.

You will know this part because it is on the passenger side of the car, under the dash pad. There will be a small vent to the front of the dash pad (have you ever wondered about that little break in the trim on the passenger side where everything meets the pad? Thats the vent I'm talking about) and a hose going from either the back or bottom of it to the fan housing. You will also see two vacuum lines attached to it, one coming in, one going out. And, of course, the linkage from the control slider attaches to the back. You can see it move when you move the slider back and forth.

You will have a hard time locating this part because NOBODY knows what it is. I believe it is called the heater control valve, or something like that. It will help to go to the Ford dealer where they have a blowup picture of the heating system, show them the part, and point to it on the screen. Otherwise they will give you a stupid look and act like you don't know what you are talking about.

For a quick fix just to get heat, pull the vacuum line off the actuator for the blend door. You can access that by removing the stopper that keeps the glove box from dumping on you and opening the glove box door beyond its normal limits. You should see the line on the left hand side of the opening. If the heater control valve is bad you will hear the blend door move to full heat with a thump and soon there will be hot air coming out of the vent. This will give you full heat all the time. The automatic fan speed will not work with this trick either.

If that doesn't give you heat, either the blend door is hung open (it actually happened on one of my '80's TC's) or the heater core is stopped up. I actually experienced that one too. If the heater core is stopped up and you have a temperature gage, you will notice an overshoot in temperature before the thermostat opens.

 

[abe_lincoln78]

You know, I just made that big post, and i realized, that wasn't where your problem was. . .

Your problem is with a thermal expansion switch thats in the engine compartment. It turns off the fan when the coolant temperature is not high enough to operate the heating system (but only when the selector switch is on heat). This one is on the coolant line that runs pressure to the heater core. You will know this because it has two vacuum lines and an electrical connector going to it. It will be made of black plastic. This switch controls whether the fan operates when you put the selector switch in the heat position.



How do I know this much about your heating system? I fiddled with one for two years before I finally got it working. I don't think there is a single heat related component I haven't replaced or inspected. Funny thing, its always the last thing you see. Stupid blend door. . . . .

 

[BMR1580]

heater control

thanks for the tip. I've had a little bit of luck getting hot air to come from the dash steadily, and now that I know how to fix the fan problem, I should have a much better winter.