69 Tach help needed

[tommyjack]

69 S code factory tach. Interior came in boxes. Tach plug from harness that plugs into tach is not cut, wires from back of tach OK. PO ran wire from plus side of coil to ignition switch. Tach doesn't work. Seems like something isn't hooked up. Once when batt was low tach arm swept across all the way and back so its getting power just not from coil. Any help would be appreciated.

[gregb]

You need to get a hold of a wiring diagram. The factory tach has that power wire running through it before it goes to the coil. It's not like an add on tach where you just attach a separate lead to the coil.

[tommyjack]

Looked at several diagrams and googled searches, some mention a wire from the fuse box. Some mention the "pink wire".

[22GT]

Attaching a factory Mustang tach to the coil in any way can easily destroy it. The tach is connected in series between the ignition switch and the pink resistance wire in the main harness.

[a228380]

...

[slim]

Light switch...tach? The posted question is factory tach. The Suntach or other add on tach is totally different from the factory tach.

[palerider]

Here is a post that I had troubleshooting mine - hope it helps.

[69M1SCODE]

The tach is "in line" with the ignition - no tach - no start. Does the engine start?

[tommyjack]

Originally Posted by 69M1SCODE

The tach is "in line" with the ignition - no tach - no start. Does the engine start?

Yep, sure does. With or without the tack pluged in.

[slim]

Originally Posted by tommyjack

Yep, sure does. With or without the tack pluged in.

The tach completes the circuit, it's in series in the run position. Starting will work either way but in the run position a burnt out/blown tach (factory tach) will open the coil circuit.


Slim


Have you looked on Tachmans Website? Stuff on there explains it pretty well.

[palerider]

forgot post
Who has pertonix with factory tach? Need some wiring help. - 1969 Mustang Supersite Web Forums
Tach is going south - 1969 Mustang Supersite Web Forums

[tommyjack]

Originally Posted by slim

The tach completes the circuit, it's in series in the run position. Starting will work either way but in the run position a burnt out/blown tach (factory tach) will open the coil circuit.


Slim


Have you looked on Tachmans Website? Stuff on there explains it pretty well.

I'll check it out. Thanks

[tommyjack]

Originally Posted by palerider

forgot post
Who has pertonix with factory tach? Need some wiring help. - 1969 Mustang Supersite Web Forums
Tach is going south - 1969 Mustang Supersite Web Forums

Thanks for the links. I have pertonix as well.

[tommyjack]

Looked at the Tach Man's site and found a diagram that shows the tach wired into the engine gauge feed harness. I thought this was for a 67-68 and not a 69. Also is the famous "pink resistor" wire found in the egine gauge feed harness tha exits the fire wall?
Thanks

[TheRktmn]

The tach wiring goes from the ignition switch, through the tach, through the pink resistor wire to the coil via the engine gauge feed harness.