green/yellow temp switch - different?

[sasilverbullet]

Supposedly these two parts are identical NOS (temp switch for a 1970 Lincoln Mk III) according to the boxes they came in - but I think that the green and yellow denotes some difference, like maybe temps? (the one on the car is green) Here's a pic - what do you guys think? [img:left]http://www.thelincolnforum.net/phpbb3/download/file.php?id=13572&mode=view[/img]

 

[eljefino]

I guess the solution would be to hook two ohmmeters up and slowly heat the two sensors in water until it boils. Unless of course you suspect the old one is faulty. Have a spec? What even did this switch control back in the day? Was mostly pre-emissions.

 

[sasilverbullet]

The one in the car is kaput. It does two things - after the engine warms up it sends a signal to a relay that allows the auto A/C to funnel hot air into the mix - the other wire is the signal to the temp gauge on the dash.

 

[eljefino]

You should be fine with either switch. If the relay switch changes at 160' or 180' it still works and would be cool to show off the analog input to a 40-year old auto climate control system. I remember a 1975 ish pontiac would cut the blower motor way down until the coolant reached a certain temp then it would blast. (wish modern cars did this, really) The varistor side of things should be a "ford standard" as they might have this sensor in various motors and the recipient dash gauge in many bodies. Besides, they'd use whatever cheapest varistor the supplier could come out with, and take its temp vs resistance curve as gospel. My WAG is plastic making in 1970 just happened to use that color. If it does two things, it would have to ground through the threads, and I can't tell from that picture how they keyed each contact so only the proper wire was attached.

 

[sasilverbullet]

If this helps, here's the wiring diagrams for the switch - mines the one labeled "ATC only" in the lower hand corner. [img:left]http://www.thelincolnforum.net/phpbb3/download/file.php?id=13493&mode=view[/img] Then on this pic - it's the one in the middle labeled thermal switch. [img:left]http://www.thelincolnforum.net/phpbb3/download/file.php?id=13494&mode=view[/img] Gratuitous big pic of the car -

 

[ARCOgraphite]

My father had an '73 460. The best big car I ever drove - hard to admitconsidering how much I loved my '65 Buick Electra 225 'vert.

 

[sasilverbullet]

Fixed - it was the temp sending unit. Thanks!

 

[eljefino]

What's that gadget on the driver's fender, auto headlight dimmer-ma-bobble?

 

[Tegger]

Originally Posted By: sasilverbullet

Fixed - it was the temp sending unit. Thanks!

I have an almost-complete set of original 1970 Ford shop manuals. The part you're asking about is shown on page 34-05-17 of the Electrical volume, in the section entitled "Automatic Temperature Control". The diagram calls the switch an "Engine Therm. Switch". There appears to be a single type of switch, so a difference in plastic color may simply be a different manufacturer, or different manufacturing time-period.

 

[Tegger]

Originally Posted By: eljefino

What's that gadget on the driver's fender, auto headlight dimmer-ma-bobble?

It's actually on the cowl, just inboard of the fender, but yes; that's the automatic headlight-dimmer. The dimmer had to be aimed just-so in order to work reliably.

 

[sasilverbullet]

Yes, it's the headlight dimmer sensor. I'm almost always asked what it is and when I'm in a playful mood, I tell 'em "it's my ray gun to shoot slow Prius' that get in my way"! Some folks stare at me for a while before they get it...