Thread: The Plymouth gets Cruise Control

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Cruise control for the 57 was a given for the upcoming trip to Tulsa.

Several years ago I used to use the universal aftermarket type that used the signal from the coil to sense vehicle speed. Unfortunatly I haven't been able to find those for a few years now. The only type I have been able to locate either use a signal from the computor or attach magnets to the drive shaft. As I don't do computors and have never had much luck with drive shaft magnets I decided to try something different.

I decided to go with a early-mid 70's GM cruise unit. I went with the simplest unit which is just basic cruise, a single button that sets speed, no tap up/down or resume, but for how I use it that's fine, and I like the fact that all that is mounted in the dash is a single momentary push button switch.

It's a little more complicated to hook up than the than the aftermarket system but most of the parts were installed as the car was going together so it wasn't that big of a deal.

What is required is a transducer, the vacume/electric switches that work off the brake and clutch peddles, speedo cables from the trans to the transducer and transducer to speedometer, the vacume pod and vacume lines and linkabe. I have about $110 tied up in the whole system that includes a rebuilt transducer, new cables, switches wiring etc.

The biggest problem was figuring out the wiring. The shop manuals and wiring diagrams I had access to were not real informative about how the whole thing worked, so a fair amount of time was spent figuring out what was supposed to happen.

Basically when you push the curise button it activates the engage and hold circuits of the cruise. When the button is released the hold circuit must remain hot to keep the cruise engaged. This involved getting a little creative with a solenoid and diode. The hold circuit additionally is supposed to run through a resistor wire, but fortunatly a ballast resistor drops the voltage the required amount.

I had already installed everything but the vacume pod and linkage when I built the car so yesterday I got around and finishing that up and trying it out. It works great, I still want to reroute the vacume lines and detail the linkage but that's minor.

In spite of the added work installing it, I suspect I may use the same set up on some other projects I have coming up.

Nice job, and really inventive. I've driven long distances without cruise, and it is no fun. Good info.


Don

That is a very nice setup Mike............I like it!!

I have, however, found a much simpler and basically free (if you don't count the tickets) alternative.....................

I am wanting cruise on my DeSoto, but have not come up with a plan. My car has Chevy steering column, with the cruise button in signal light handle. I would like a set up that I can use that stock cruise lever. Any one with any suggestions? I need simple and not expensive (cheap).
Oh yeah, the engine is 392 Hemi with 2-4's, stock Weiand intake.

Jack

If you already have the GM column with the button you might consider the GM style I'm using. I pretty sure the built in button serves the same purpose that the solenoid I had to built.

Here's what would be involved. You will need a transducer, (available rebuilt for about $75). New Speedo cables, one from the trans to the transducer one from the transducer to the speedo. A vacum pod and bracket. My Pod and bracket was used and came from a Mid 70 Chevy Van. The bracket was simply mounted to one of the bolt that hold the rear water passage block off plate on.

The linkage from the van was also modified to connect to the carb. You will also need a brake peddle mounted switch. It acts to break the circuit to the cruise and shut it off and also has a vacume port that dumps the vacum in the pod the release the carb linkage. Finally you will need either a piece of resistor wire or a balast resistor. If yo can find one they make a combination switch that has a plug for the brake lights, the cruise circuit and the vacume dump. It should bolt in in place of your brake light switch on the peddle.

After you mount the transducer and connect the cables you will need to run 2 wires from inside the car to the transducer amd one vacum line from the transducer to the brake pedddle switch (if your running a stick like I am your will need a switch on both peddle and have to "T" the vacum line.

Once you figure out where everything goes you should be able to install it in a Saturday.

If you think you might want to give this a shot I'll see if I can scan the wiring and vacume diagrams and E Mail them to you. (It might take a day or 2 to get that done though).

Thanks Mike. I will get in touch with my buddy (more mechanically inclinded thant me), and see if he will help me tackle it one Saturday.

Jack