I was doing a little digging into EATC system operation and came across the following thread.....
http://www.foxtbirdcougarforums.com/index.php?topic=39114.msg451153#msg451153
I found a post in there that piqued my interest considerably. Here it is....
I'm sorry.....
WHAT? A cabin temp sensor?!!!!?????
I never knew about this let alone noticed it when I've been messing about in that area....
Someone please educate me on it.
Well it's there. I've seen it when the radio surround trim is off. I haven't tried to remove it but the thing works, which is all that matters to me.
I'm curious about its operation more than anything else.... Meh. Time to pony up for that shop manual I've been eyeballing anyway....
According to pages 108-109 of the 1988 EVTM there is an in car temp sensor in the dash as well as an ambient temp sensor in the evap case. So the system has two temperature sensors.
The dash one is what I'm interested in.
News to me also. I just knew about the one monitoring coolant temp to the heater core.
guys,
the trim around your radio & ash tray & eatc ,, at the top rolled in area of that piece of trim there is a cut out from the factory.
poke your finger into that approx 3/8'' x 1'' opening and you may find the j or k wire type temp sensor leads.
on my 20th the sensor is not there,, its on deeper into the innerds of the dash. the factory wire would not reach its intended home.
Its used when you set your eatc to Auto,, the eatc will ramp the blower up and down on its own?
i did not know about an external temp sensor other than the one on the heater core
Been busy as heck. Forgot all about this. My shop manuals came in. Time to research this. I'll post when I can.
Please click on the two links. They're pictures. Haven't quite figured out how to insert the actual images from Google Drive on here yet.
https://drive.google.com/file/d/19Og6H_pz0fwbPkZmkHo8dYZQOxhOh8hl/view?usp=sharing
https://drive.google.com/file/d/19PDau6qmuW03rjb6roA6q8oj1_8p-yKl/view?usp=sharing
Sorry for the long wait. I actually pulled the In-vehicle sensor today and cleaned it. It was quite disgusting.
It may even be so bad that it no longer works. I'm looking through the test procedures in the shop manual now.
Anyway, whether or not I'll need them does ANYONE actually know the part numbers for these or the Motorcraft numbers? I know they're quite difficult to come by.
EATC ATC HVAC A/C Temp Sensor - 1985-1990 Thunderbird, Cougar - Motorcraft YH-434
eBay link: https://www.ebay.com/itm/Motorcraft-YH-434-EATC-ATC-HVAC-A-C-Temp-Sensor-1985-1990-Thunderbird-Cougar/184006024335?fits=Make%3AFord&hash=item2ad79d1c8f:g:8a0AAOSwONddsIIp
1984 - 1989 Lincoln Mark VII A/C Ambient Air Sensor - E4LY-19E642-A
eBay link: https://www.ebay.com/itm/1984-1989-LINCOLN-MARK-VII-A-C-AMBIENT-AIR-SENSOR-ASY-NEW-OLD-STOCK/133131113286?hash=item1eff3b9346:g:puMAAOSwqLFdQwhZ
FWIW, the factory sensor in my car looks just like the one in the eBay link that is listed for the Mark VII.
Man! When I am parting out cars, I've just been throwing those away! I didn't know what they were. Gotta keep 'em now!
Found the following:
https://www.thelincolnmarkviiclub.org/phpBB3/viewtopic.php?f=22&t=11677
I cannot confirm anything with regards to accuracy of that yet..... Still hunting for the actual source as the person who posted it didn't cite anyone or anything.
*EDIT*
Might be from here.....
https://www.justanswer.com/ford-lincoln/7yps8-lincoln-mark-vii-lsc-1989-lincoln-mark-lsc.html
So the one for our cars (the black 84-89 one) is just a resistor and some other component. Figure out what they other component is and a rebuild is a simple 5 minute solder job.
That reads very much as if it was taken directly from a Ford TSB page.
Is the other component a thermistor? Anyone have one they can check the markings on? If the only two components on the sensor are a resistor and a thermistor those are available from multiple sources. Just need the values and it's a simple unsolder the old components, solder in the new, and it's done. It's probably a couple cents in parts.
Indeed it does. I just can't confirm it at this point.
I found some time to pull mine out of the dash and found out that my memory is not what it used to be as my sensor is not the Mark VII version as I thought.
I'm tempted to buy one of these for the spare parts bin.
My hunt for a clean one for the heater box continues along with an NOS brake prop block for a rainy day....