Combines 8030 tachometer

Is your alternator charging goodIJ The third terminal on the alternator is your input into the tach. A multimeter on the input of the tach should rule out wire and connection issues. An oscilliscope would tell you more. A tach that doesn't work is usually a problem with the alternator.

service manual has a check out proceedure - 8030 picks up off teeth in starter ring gear via sensor - pull out sensor and see if end looks ok first. 70264587 is partn