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Tach Wiring

70 Steed

Full Member
Joined
Sep 13, 2011
Messages
268
I've searched the forum and haven't found the answer. I have a '70 with stock 302, stock wiring harness, stock cluster and stock switches. The tach signal wire is a no brainer and I figure I can find a place to attach the ground wire under the dash.

My question is where is the best place to attach the positive and the tach light wires. By best I mean the easiest and most reliable. I know the light wire should be attached to the wire that dims the cluster lights but that is not important to me because I always run the cluster lights at the highest setting. So just a switched 12 volt would be fine. I'm not as flexible as I use to be so getting under the dash to attach to the terminals on the switch is tough. However I'm liking the idea of splicing into the middle of a wire in the harness.

I just thought some of you might have a trick way of doing it.
 

jlylec

Sr. Member
Joined
Jul 5, 2012
Messages
891
I've searched the forum and haven't found the answer. I have a '70 with stock 302, stock wiring harness, stock cluster and stock switches. The tach signal wire is a no brainer and I figure I can find a place to attach the ground wire under the dash.

My question is where is the best place to attach the positive and the tach light wires. By best I mean the easiest and most reliable. I know the light wire should be attached to the wire that dims the cluster lights but that is not important to me because I always run the cluster lights at the highest setting. So just a switched 12 volt would be fine. I'm not as flexible as I use to be so getting under the dash to attach to the terminals on the switch is tough. However I'm liking the idea of splicing into the middle of a wire in the harness.

I just thought some of you might have a trick way of doing it.

I would think you'd want to splice it onto the wire leading to your other dash lights so it's only on when the lights are on as opposed to whenever the key is switched to on. So you'd splice it onto the wire coming out of the light switch when it's pulled at least one click out.
 
Last edited:

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,448
Blue - red wires going to the cluster are the light wires. You can get to them easily by removing the fresh air box at the cowl.
 

Stroppe-Envy-77

Bronco Guru
Joined
Jun 15, 2009
Messages
1,011
Blue - red wires going to the cluster are the light wires. You can get to them easily by removing the fresh air box at the cowl.

This is one of the best things I ever discovered for working on anything behind the driver's side dash. It's like a magical access point!
 

Crush

Contributor
Bronco Guru
Joined
May 30, 2007
Messages
3,463
Loc.
Greenbottom, WV
Also remove the drivers seat. Lets u stretch out longwise and not have to twist up in a knot to get under the dash
 
OP
OP
70 Steed

70 Steed

Full Member
Joined
Sep 13, 2011
Messages
268
Thanks Viperwolf. I forgot about the removing the air box trick.
 
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