BrickBoard Archives
The files contained in this listing have been automatically archived from the active forums. Because the vast majority of posts are now in one place, this archive is considered legacy. You should use the SEARCH feature OR choose your topic and select date tabs within the forum you choose.
Re: Tachometer Hook-up[200/1984] posted by Don Foster on
Sunday, 13 June 1999, at 4:21 p.m.
Larry --
The "heavy gray wire" connects directly to the spark coil -- to the same connector attached to the ignition module. One connector has steady 12-volts, the other connector pulses. This is easy to find with a small 12-volt test lamp. This pulsing side connects to the tach.
On an original gas car, the "steady 12-volt" wire should be brown and hook to coil terminal #15. The "pulse" wire should be red-white and hook to coil terminal #1.
On my car old '83, that lead comes out of the main harness along with the other harnesses for the cluster. Others on the BB have said it's there -- but often buried. Since your car was a diesel, it might indeed be missing.
I believe the gray wire is "heavy" because it's shielded -- probably to reduce radio interference. If you find an increase in ignition noise on the radio, you'll probably need to fabricate a 5' shielded lead going from the cluster into the engine compartment (shield grounded) and then to the coil (unshielded OK once inside the engine compartment).