1973 roadrunner aftermarket tach

[midnightrider1818]

Hey guys bought a aftermarket tach for my 73 rr. Question is where did you guys get your 12v switched source from and where did you plug your light wire in. Hate cutting wires. Ralleye dash by the way

 

[Moparmatt72]

If you don't have one for buy a test light probe a connector under the dash with key on and then splice, same with the light, trace the headlight switch wires off the switch, and with the test light turn on your lights and splice. Just double check both by turning on and off both the key and headlights to make sure it's a key on power only not a live feed wire

 

[ODZKing]

You should have a molded plug under the dash and hopefully an empty space in it. I can't remember if it is orange or yellow. One is accessory the other acc lamps.
It is NOT the red one, that is live to battery. There should be one near the left side that the rear defrost lamp is plugged into, follow that.
Anyway, it should look like this.

 

[idrivemopar]

As ODZKing says, the orange molded plug is for lights, the red one is an accessory feed direct to battery buss. You can use the accessory feed on the fuse block, its the one on the lower left side and switched with the key, the right side one on the fuse block is direct to battery buss. Just a note, the yellow molded plug is an accessory feed, used for ac/heater control, rear defogger, and optional factory tachometer, and it is tied into the accessory buss.

 

[YY1]

I've been known to simply push the tinned end of the + tach lead under a "lightly" used fuse, that gets power when the key is on.

If I have time, I add a piggy back "stake-on" to the back side of the fuse block, and do it "right".