Cruise control: is speedo signal important?

[wagonist]

After driving to Canberra & back on the weekend, my car is badly in need of Cruise Control.
It was very difficult to keep the speed constant, and imprtantly on the speed limit due to the double demerits kindly on offer from NSW & ACT police.

Anyway, I've got a complete early Subaru Liberty system sitting at home which was destined to go onto another car, but is now surplus.

Should there be any problems if I simply bridge the signal wire from my Caldina's speedo signal to use?
I imagine that the cruise ECU simply wants to keep the same signal once the "Set" button is pushed & is only comparing the incoming signal to the "stored" one so it know whether to release or pull the throttle.

[CrUZida]

It depends what signal the Subaru cruise control wants. If the Toyota setup is unable to produce the right signal, the cruise will never work. And if you don't know the signal you'll spend weeks trying to get it working.

You can buy aftermarket cruise kits that are designed to work with the stock signal.

[wagonist]

I had an aftermarket system on the last Caldina. It worked crap.
Admittedly, it needed a very fast response time to keep up with making sure the diesel didn't go off boil, but also wouldn't resume to the same speed, buttons needed to be pressed carefully, ... (stupid US built POS)

It's no great drama to temp wire up the system to see if it works before doing permanent connections to brake, clutch, etc switches.

IIRC, the speedo wire in a Toyota is Purple with Yellow stripe?

[CrUZida]

Toyota tend to change wire colours a fair bit.

And there are 2 speed signals.
One goes from the speedo sensor to the dash.
The other goes from the dash to all the car ecu's (engine ecu, pps ecu, cruise ecu).
They are different signals.

[wagonist]

My diesel Caldina had a wire running from the ABS unit to the dash for the speedo.
This one also has no gearbox sensor, but runs off the ABS sensors.

So I'm looking for a wire than runs from the ABS unit to the ECU, which may then have a separate wire to the dash.
Looks like its out with the multimeter & instrument cluster to back trace what's what...