[lrush]

Does anyone have a wiring diagram for a vintage SW tachometer? Tach is a SW model 977 J, and the ignition control (sending unit) is a 990 B, with 5 terminals-light, tach, batt, grnd, & ign. Tach has 4 wires--red, white, black, & green. The car it is going in has points ignition.

Thanks, Lee

[S10 Racer]

Here's a diagram.

[lrush]

Thanks,
I've seen that diagram before, but it doesn't show how to wire the transmitter/sending unit. Thank you anyway.
Lee

[67Mustang Al.]

Originally Posted by lrush

Does anyone have a wiring diagram for a vintage SW tachometer? Tach is a SW model 977 J, and the ignition control (sending unit) is a 990 B, with 5 terminals-light, tach, batt, grnd, & ign. Tach has 4 wires--red, white, black, & green. The car it is going in has points ignition.

Thanks, Lee

From my understanding of tach wiring your 4 tach wires should be Red, ( power wire-attached to your tach terminal on your 5 terminal switch.........assuming that your tach wire on your 5 terminal switch is switched to +ve)
White wire( power wire for tach gauge globe- wired to your "light" terminal.
Black wire to ground.
Green wire from tach( trigger wire) to go to the negative side of your ignition coil assuming your vehicle is negative ground.
Thats how i would do it.
Al.

[S10 Racer]

Originally Posted by lrush

Thanks,
I've seen that diagram before, but it doesn't show how to wire the transmitter/sending unit. Thank you anyway.
Lee

What Make & Model are you trying to wire? If it has points, it has a coil. The green wire goes to the neg. (-) side of the coil. Can you post a picture of your setup, I'm a little confused.