Underdash routing
 

I have a 66 lemans and installing an American auto wire upgrade kit. Could someone share some photos either of stock or upgraded under dash wiring. Trying to see little stuff like where does the rear harness come out and tie to the main? Behind dash routing. Etc. Thanks

Is the wiring already out of your '66?

I can't speak on AAW harnesses and/or wire kits, but my M&H was a factory-correct plug-and-play harness.

The rear "Strap" harness is on the DS, running up the foot well near the fuse block's LS.

If you're replacing the dash harness, IMHO it's far easier to remove the entire dash with the harness attached just as it was installed. Replacing the harness on the bench.

JM2C
Cheers

Thank you Jeff! Exactly what I needed. Yes all the wiring was already out of the car when I got it. And the American auto wire is a great kit but there are differences, one being it does not use a ribbon type to go to the rear. Not a big deal but I'm starting from scratch and manuals only show so much.

Underdash wiring
 

One idea I have for you, which is a copy of the way GM did it.

On all 64-67 Tempest, Lemans & GTOs. Regular gauges or rally (all were made like this) the main wiring which comes up from the fuse-block; in behind the gauges, taped into that harness is one plastic "arrow."

On the back of the gauge housing just above where the speedometer cable threads on you will see a small hole. This hole is in every gauge housing (64-7) A body Pontiac, the arrow that is part of your dash harness plugs into this hole.

That arrow takes the strain off of any bulb socket(s) and/or plug-in(s) which would otherwise take all the weight of the harness.


Once the arrow is removed the first time it is typically damaged beyond re-use. Blue outline: if it is cracked or broken you should replace it. I used to use a pair of tiny ty-wraps and or electrical tape to secure the new arrow to the bundle. (Make sure it is in the same place +- 1/4".)