I am considering adding a aftermarket cruise control. Through my years of research I swear the I read that the FB speedometers are where the speed sensor is. I think it uses a Hall effect and sends a signal out from the cluster through the brown wire. Unfortunately I can't find where I read this information to confirm. I did find in the factory manuals the speed sensor (brown wire) coming from the cluster, but I am second guessing myself. Before I contact the manufacturer I wanted just to confirm that I understand what I think I understand.

 

Mechanical,cable driven from speedo drive gear in tailshaft of transmission.Speed sensor... that's waaay too high tech for 1st gen,lol.

 

No, he's right, that's exactly how it works. There's a pickup in the speedometer head that sends a signal to the cruise control unit. It may also go to the emissions computer, but I'm not certain on that.

The speedometer itsef is mechanical, but the speedometer sends a signal too.

 

I stand corrected. Sometimes don't remember as much as i used to.

 

Thanks PeeJay for the confirmation.

 

Why would you consider adding an aftermarket cruise control unit instead of retrofitting an FB-original unit to your car? I'm considering doing that very thing, adding an FB cruise unit back onto my car after I deleted it previously.

 

I kinda miss my factory Cruise Control, as well. Its handy on long drives on the freeway, and is definitely less tiring on the driver (*as I contemplate the drive to SS22 this year...).

My factory CC failed due to unknown reasons, and I suspect it was the control box in the Drivers side Bin that got corroded, though it looked okay to the untrained eye. The problem was that, when driving - if you engaged the Main Switch for CC, the throttle would advance and accelerate the car non-stop in whatever gear you happened to be in. This was a little concerning if you weren't expecting it.

I pulled the underhood Actuator, the associated cabling, and the Control Unit from the bin and put it all in a box in hopes of someday retrofitting it. Maybe you can be the inspiration!

 

My guess is availability. Tracking down an OE and praying it works vs dropping in a tried & true Rostra unit (I've installed several of these, they work a treat). Plus the Rostra has a wide selection of switches and mounting options from stalks to control pads.

If you already have an OE unit and it works, then that's definitely the way to stay.

 

Have you ever wired in one of the Rostra aftermarket units using the factory switches? That would be the main thing I'd want to personally retain, the functionality of the OEM switches.

 

Negatory, I've only ever added them to vehicles that came without. I imagine you could crimp on the appropriate terminals and pin the factory switches in to the aftermarket connector.

 

Signal from the gauge cluster goes to the control box behind driver's seat as well as emissions computer in passenger footwell for 84-85 models. Download the wiring diagram PDF for details.

I'm using the signal for a stand alone ECU but I also kept the factory cruise control stuff. It works Ok with my aftermarket throttlebody except it doesn't do a great job maintaining a steady speed. I thought it might be vacuum related so I put a reservoir in-line with the actuator. That helped it bounce back up to speed better on hills but now it over shoots the target, if I set it to 75 my speed will jump up and down between 70 and 80. With the Nikki, it used to only fluctuate 1-2 mph.

 

That may be a throttle body sizing issue. I wonder if you could compensate by mounting the cable on a longer arm on your throttle body, as a mechanical hack.

Every OE cruise control unit I have had died from water intrustion thanks to bin rust.

 

I decided to abort the idea. did make for a scholarly discussion though. Thank you to all who have participated