What is this for?

[protouringstang73]

My dad is about to make his wiring for his 1973 Mustang. He discovered this red relay, the wierd about it is that it has a connection to the speedometer cable? Does any of you know what this is and is it something that has been installed from factory? The car has been driving in Denmark from day one if that helps anyone

 

[protouringstang73]

The underside of the relay

 

[protouringstang73]

The relay together with the wiring

 

[protouringstang73]

And here it is connected with the module on the speedometer cable

 

[Carolina_Mountain_Mustangs]

I have never seen that one before. I think the wiring diagram is on the Forum site to download. You could maybe find it located there will need to be for 73 each year has some differences. Maybe look for the wire colors? Maybe Midlife can answer this one.

 

[basstrix]

Looks like parts for a cruise control system. Does it have the diaphragm under the hood connected to the throttle?

 

[MikeGriese]

Try googling the part number.

It's an AC defroster relay. It turns off the compressor if the evaporator temperature probe detects ice if forming in the plenum.

 

[bkdunha]

I believe it to be an emissions control module for 73. I am away from my books. I think it is a spark control box.

 

[Carolina_Mountain_Mustangs]

Try googling the part number.

It's an AC defroster relay. It turns off the compressor if the evaporator temperature probe detects ice if forming in the plenum.

Why would that hook to the speedometer cable?? When I looked at the wiring diagram I looked for anything related to speed and there is a speed sensor in the wiring at C-85 grid. But wiring does not match what is on the relay. Might be unique to maybe KPH cars or cars built in Denmark? I don't know for sure.

 

[rocket366]

P13 from Data link above for 73 Wiring

http://www.7173mustangs.com/images/1973_full.pdf

EGR CONTROL MODULE

Paul

 

[DK73]

Well yes it is cruise control Daniel [sMILING FACE WITH SMILING EYES] My car has it to [THUMBS UP SIGN] But I have not eny wiring harness.. Regards Lars

Sendt fra min E2303 med Tapatalk

 

[secluff]

That is what Ford called a exhaust gas recirculation control switch. It took the signal from the speed sensor in the speedometer cable and was used to control the EGR valve along with all the other devices such as the ported vacuum switches. Was used on 73 351C, 400, 429, 460, and 460 interceptors. In 1974 was only used on the 460 interceptor's, as 1975 saw the introduction of catalytic converters and a major change in EGR and related emissions systems.

A lot of people mistake this for the cruise control speed sensor since it is in the same location as a car that has factory cruise control. Cruise control was not a RPO (Regular production option) on the 71-73 Mustangs.

 

[Carolina_Mountain_Mustangs]

That is what Ford called a exhaust gas recirculation control switch. It took the signal from the speed sensor in the speedometer cable and was used to control the EGR valve along with all the other devices such as the ported vacuum switches. Was used on 73 351C, 400, 429, 460, and 460 interceptors. In 1974 was only used on the 460 interceptor's, as 1975 saw the introduction of catalytic converters and a major change in EGR and related emissions systems.

A lot of people mistake this for the cruise control speed sensor since it is in the same location as a car that has factory cruise control. Cruise control was not a RPO (Regular production option) on the 71-73 Mustangs.

Humm my 73 351C vert does not have one, is that bad? It was a California car if that makes a difference. Never had the dash out of the Mach 1 to know about it.

Hey learned something new today it is good.

 

[rocket366]

Connected to speedo cable to sense cruise speed to introduce exhaust gas into induction.

WHAT A GREAT IDEA! NOT!!

Engines were being retarded to meet emissions what a waste. By 73 the HP was way down.

I helped my father S Can all the smog BS that came on the cars we owned with pleasure and

no repercussions at the time. AHH the good Ole Days. BTW you wont find any of that BS

on my smog Exempt 73.

I never want exhaust injected into my intake HELLO.

Sorry 4 Venting

Paul

 

[secluff]

That is what Ford called a exhaust gas recirculation control switch. It took the signal from the speed sensor in the speedometer cable and was used to control the EGR valve along with all the other devices such as the ported vacuum switches. Was used on 73 351C, 400, 429, 460, and 460 interceptors. In 1974 was only used on the 460 interceptor's, as 1975 saw the introduction of catalytic converters and a major change in EGR and related emissions systems.

A lot of people mistake this for the cruise control speed sensor since it is in the same location as a car that has factory cruise control. Cruise control was not a RPO (Regular production option) on the 71-73 Mustangs.

Humm my 73 351C vert does not have one, is that bad? It was a California car if that makes a difference. Never had the dash out of the Mach 1 to know about it.

Hey learned something new today it is good.

David, after 43 years, there is a good chance a lot of those sort of things got "Tossed". The two piece speedometer cable with the speed sensor was a 72 NOX and a 73 (with the 9E447 EGR switch) part and was probably discontinued by Ford before the 80's arrived. A lot of them were probably replaced with the more common single piece cable. I believe NPD offers the lower cable, but their site indicates that it is out of stock.

 

[secluff]

Connected to speedo cable to sense cruise speed to introduce exhaust gas into induction.

WHAT A GREAT IDEA! NOT!!

Engines were being retarded to meet emissions what a waste. By 73 the HP was way down.

I helped my father S Can all the smog BS that came on the cars we owned with pleasure and

no repercussions at the time. AHH the good Ole Days. BTW you won't find any of that BS

on my smog Exempt 73.

I never want exhaust injected into my intake HELLO.

Sorry 4 Venting

Paul

rockett366, no need to be sorry for venting. All said was the truth. The Government was putting big time pressure on the car manufactures, who were scrambling to meet deadlines set by "Big Brother".

I never liked the ideal of recirculating hot exhaust back through the intake Under a carburetor full of gas. With all 73 model cars now carrying the extra weight of the "Crash" bumpers and emissions control strangled engines, performance and fuel mileage were just about non existent. It was funny to see 455 Trans Am's and 454 Vetts with about the same horsepower of a 351 4bl!!

I watched my friends do what you and your Dad did. Hoods went up and trash can were pulled up close. Unfortunately they also tossed a few Rev Limiters. They figured anything under the hood that didn't make horsepower was evil and needed to be S**t Canned!! LOL

 

[MikeGriese]

Try googling the part number.

It's an AC defroster relay. It turns off the compressor if the evaporator temperature probe detects ice if forming in the plenum.

Why would that hook to the speedometer cable?? When I looked at the wiring diagram I looked for anything related to speed and there is a speed sensor in the wiring at C-85 grid. But wiring does not match what is on the relay. Might be unique to maybe KPH cars or cars built in Denmark? I don't know for sure.

Hmmm... Google may not know everything after all.

 

[protouringstang73]

I will say thanks to everyone who have been really helpfull in this tread! So nice to see so many trying to help and some of you came with some very interesting stuff to read! So thanks, my dad is now a step forward!

 

[judge]

This is the section of the diagram that covers your parts. Yhe ambient air sensors are installed in the front of the door post (almost level with the antenna cable hole), I don't believe that they are visible with fenders installed.