Heater fan won't turn off

[94linc]

I have a 1994 Lincoln Town Car and yesterday the heater fan decided it wasn't going to turn off any more. No matter what I do. The led indications work normally as far as increasing and decreasing the temp and changing from floor to ac to defrost or vent or whatever. And when I push the OFF button, it says it's OFF, but the fan is still blowing away. Also, It sounds noisier when I turn it off, but I think that is just a diverter moving to a new position; the watchacallit that forces the airflow to go a different route, like when you change from defrost to floor for example. Maybe (I'm guessing) when you turn it off, it sends that diverter to a 'home' position, but since the blower is actually still blowing, there's an air flow conflict - hence the noisier sound.

Thanks in advance for your help!!

[8BudweiserFan]

I have similar problem with a 1990 LTC. Temperature settings have no say in what comes out the vents. I never know when it's going to blow hot air or cold air. one thing I did learn is that if I want heat, I have to get the car at least past 30m.p.h. then slam on the brakes. When I do this, I can hear the temperature blend door shut. When I finally do get heat and turn the system to OFF, it stays running and air comes out on the floor. People look at me like I'm nuts for having the window down in the winter.

[94linc]

My temp control still works; if I put it on max (90 degrees) it puts out hot air and changes to cold air if I drop the setpoint to 60. So I haven't lost that, it's just that the blower fan is on all the time.

[Towncar]

Check your "Blower Speed Control".
I disassembled mine, found a resistor soldered badly on the "control circuit board", resoldered it and it's been working fine since.
Others (other TC owners) simply replace the "speed control" and have good results to report.

[94linc]

Steven,
Thanks for the info. I should have time tomorrow to (try to) take it apart and check it all out.

The only 'speed control' is the thumb dial on the far right of the heat/ac console. Is that what you're talking about?

Also, do you know, is that whole display unit [[with the led readout, switches along the bottom (ac, max ac, floor, vent, defrost etc) and 'speed control' ]] replaceable as a unit? And is it very tough to get out?

Thanks a lot!

[Towncar]

Originally Posted by 94linc

the only 'speed control' is the thumb dial on the far right of the heat/ac console. Is that what you're talking about?

No. There's another one....
Go here: to my lincoln pages , look down the right column for "blower speed controller" A and B links. I'm almost positive 1994 is different from 1996 as for the actual location of this speed controller.... I can't say exactly where the 94 controller is located. I will look around the forums though, cause I've seen the different locations posted somewhere.

I'm sure that Temp Control Console can be replaced, although I have no data on the process.

[Towncar]

Originally Posted by Towncar

..I will look around the forums though, cause I've seen the different locations posted somewhere.

Here's another thread on the subject, I'll keep looking.


Another Post
Another Post


It helps if I put the links

[94linc]

Ahhh.. that 'speed controller'. I had no idea it even existed. I just figured everything was in the module in the dash. That's a great link, to the pdf explanation, on your site. I found another one on lincolnsonline.com that shows a similar replacement procedure for this assembly. It was for a 2001 TC and in the same general vicinity (left side of firewall), so I'm pretty sure that is where I will find mine, a 1994. thanks again!

[Mike2755us]

Hi Towncar guy, i have been looking for a thread like this for awhile and i don't know how i missed this... However, mine has been working since i set therm. to 70 degrees and when it stays cold again i guess i will go to 30 mph and slam on the breaks lol....ty.

[94linc]

Glad that's working for you. I plan on replacing my speed control unit as soon as this blizzard blows over. Will post results...

[94linc]

Well, you're not going to believe my good fortune. I can hardly believe it myself. I ordered a power
transistor for the speed control module on a hunch (Part number MJ11028). It arrived yesterday and I managed to install it late last night. It had been riveted to the board - obviously not meant to be a component level repair part - so it took a little persuasion to replace it, had to drill the rivets out etc.
Anyway, I just put the module back in the car a few minutes ago and lo and behold, it works
now!! UNFRIKKINBELIEVABLE!!!! It was a total guess, albeit an educated one, but never looked
at a schematic, never broke out the meter, just took a wild guess. I'm thrilled! While I was
screwing around this morning, I was looking up junk yards; that's how confident I was. I
figured the transistor was definitely worth a shot, but I'd probably be going to a junk yard
after it didn't work to try and find the whole module. Now, of course, I won’t have to bother with any of that.

Thanks to everyone for their input, especially “Towncar” Steven who got me on the right track! Anyone with Towncar issues should visit his site (there are links to it in the thread entries above), it is a valuable reference site – with pictures and everything!!

Here's a link to the Lincoln site:
http://www24.brinkster.com/sdhartney/linc/linc.htm