I dont think is a speed limitter or sensor. My ute doesnt behave any differently with it plugged in or removed. But ever sinve i removed my dash and stripped the speedo to clean it (cause it was sticking) and put it back together the fuel and temp gauge are not working. Turn the ignition on the needles move up about 5mm then go back to zero. I thought this thing had something to do with it cause its the only electrical thing I unplugged appart from pulling the main plug from the back of the dash. Does anyone have a wiring diagram for the dash on a 1979 datsun 1200 ute. Might help me to figure what goes where. Is there a way I can hard wide the 2 gauges?? Or just drive by chance till I get the SR20DE conversion done and fit the silvia gauge cluster.

I'll find it in my manual. It really looks like something i had on my speedo.

ok, here we go...
It's for the Throttle Opener Control System.
"The function of the throttle opener is to open the throttle valve of carburetor slightly in vehicle deceleration. Durring deceleration, manifold vacuum rises and a quantity of mixture in the enigne is not sufficient so that a normal combustion can not continue, and a great amount of unburned HC is emitted." - 73 sevice manual

Ah, speed sensor. I don't think that's a speed sensor.

The wiring diagrams have it, so does the Emission Controls article. For 1973 models, the outgoing wire is Blue/with/red. Unlike the photo here.


Perhaps it is an external (aftermarket) voltage regulator. The stock one is in the Temperature gauge (rectangle gauges) and puts out 8V. Should be easy enough to test. The voltage regulator controls both fuel and temperatur gauges.

It is a spying device...the engineer planted it in your car.....watch out!