Another Wire Question

[dprio34]

I'm in the middle of the Retro Sound Stereo Install, and I noticed a "dangling wire" behind the dash. It is solid Red, so I'm guessing it is either "Red 63" for the Windshield Wiper Switch or "Red 284" for the Headlamp to Stop Light Switch.

It has an O Ring at the bottom and it is "paired" into the main harness (or exists the main wiring harness) with the Brown wire that goes through the firewall next to the Gas Pedal/Accelerator. I believe the Brown wire is Brown #262.

If anyone has any ideas on which Red this may be, most appreciated.

Cheers!

 

[Steve83]

An "O-ring" is rubber; that's a "ring terminal". Based on its position under the dash (near the ig.sw.) and your description that it's close to a BRown wire, I'd assume it's the power to the ambient temperature switch.

(phone app link)


Follow the red wire...

 

[dprio34]

Many Thanks @Steve 83 for the info, diagram, and proper nomenclature!

If you have time for another rookie question...What exactly would the ambient temp switch control? Some type of emissions controls?

I just put on an Edelbrock Intake 2121 and 500 CFM Carb, is the Ambient Temp switch needed or recommended? Can I just put some shrink tube over the ring terminal and tie it out of the way?

Thanks Again!

 

[DirtDonk]

It was on '72 and '73 trucks only I believe (there's a study on it elsewhere) and visibly it's a metal plate with two screws holding it to the driver's door hinge pillar. That's the sensor.
There is probably a switch on your transmission too, that senses what gear you're in (I think it's activated in 3rd gear on a manual trans, but others would know for sure) and adjusted your ignition timing based on temps and load.

You don't "need" it I'm sure, since most vehicles run fine without it. And if you have a different ignition system and/or transmission, then the need is moot anyway.

Sorry if any of that info turns out to be less than accurate, but at least it's there to give you an idea of what you might be dealing with.

Paul

 

[DirtDonk]

Meant to ask if you even have that sensor in the door pillar still, or just have the hole like so many do.
If you peek down behind the dash on your upper kick panel, is there a large round hole with a few wires coming through?

Paul

 

[dprio34]

Paul,

Thank you for all of that. Very Interesting. Yes there is a plate on the door pillar/post. It has, "Ford STEMCO" Stamped on it.

And Yes, the front of the Transmission has a connection on it between bell housing and 2-3 Shift Rail.

The lead circled in red goes into the front door post/pillar to the Ambient Temp Sensor.