Finishing resto on 69 442, original wiring harness re-used, however coil/wiring missing when purchased (no motor with car). I purchased a wiring diagram but I unable to identify the wire color for the tach leading into in the engine compartment.

Please help identify correct wire with wire color, connector type and pathway? I'd rather not pull the dash apart to trace the wire.

PS. I converted the distributor to HEI, I have done same to other 68-72 GM a- bodies with no necessary mods to tach, can I do the same with the olds? Or is a mod required necessary for the factory tach to operate properly?

 

People often say "HEI" to mean any electronic distributor. ASSUMING you really mean a GM coil-in-cap HEI (and not a Pertronix or other aftermarket conversion) then simply connect the coil wire to the TACH terminal on the HEI.

 

There are 3 wires that go to the back of the tac/clock. An orange wire provides a constant 12V for the clock. A gray wire provides power to the dash lights. The wire for the tach is brown and it has a 2 Amp in-line fuse under the dash. The wire routes through the 3-hole grommet in the firewall into the engine compartment and then across to the negative side of the coil. As I recall, the connector at the coil is a "U" type. I think the connector at the tach is an "O" type but I'm not sure at the tach. I used a Pertronix set-up in my '68 and the tach works fine. The '69 wiring is the same for this as the '68.

Randy C.

 

It took me a second to figure out what an "O type" connector was. My mind kept reading "Type O".