My '77 Nissan manual says it is is on the "side dash". From the sketch, it appears to be on the driver's side, under the dash, near the ECU. It is held on by 2 bolts and appears to have a connector with 6 slots, but only 5 wires in it. From further research, it looks as if the wires colors are: w/r, l, g/l, b/y, w/b. (L=blue, b-black). Hope this helps.