'72 Firewall Help

[tjsblazer]

Next wire routing question:
Where does the main rear tail light harness route up at cab side. Where does it enter.
I know it runs down the Lh Frame rail and the rear grommet inserts at the last cross member but where does the front grommet insert? This is the flat 4 wire ribbon style harness with the round integrated grommet/connector on each end.

[hemi43]

Originally Posted by tjsblazer

Next wire routing question:
Where does the main rear tail light harness route up at cab side. Where does it enter.
I know it runs down the Lh Frame rail and the rear grommet inserts at the last cross member but where does the front grommet insert? This is the flat 4 wire ribbon style harness with the round integrated grommet/connector on each end.

I circled the tail light grommet in red but you can hardly see it.

[tjsblazer]

Dan. Thanks. That was the last piece of the puzzle for me I think. I laid all my wireharnesses out on the garage floor and got it figured out. I never took any pictures of wiring before I took it apart. I work in automotive assembly and thought the wiring was so basic I would never forget it. But 1.5 years later, big mistake. My memory isn't what it used to be.

Decided after looking at the shape of my wireharnesses they aren't great. Many splices and cuts over the years. I'm going to use the AAW upgrade kit #510089. This also gives me some additional circuits I can use for seat heaters and some 12v power ports in the passenger area.

I am also running all electric gauges so I will shave the firewall for the original Speedo, TSC, and fuel sending holes. The fuel sending will be joined to the tailight grommet hole in the tunnel area which is the way the upgrade kit is set up.
For Tach, Speedo, oil pressure, etc. I'll use the original grommet hole for the Oil pressure pipe in the tunnel area.

This should clean it up a bit and get me everything I need.
I'll post updates and pictures in my build thread when I get to it.

Thanks again for everyone's help in this. J.

[hemi43]

Even though I'm using a late model engine in my Blazer, I opted to plug all the firewall holes with proper sized grommets because I was reluctant to do anything to the truck that couldn't be reversed. Just my opinion, but it might be something to think about in case the next owner wants to reverse things back to original. These trucks will only go up in value and you don't want to do something that may hurt it's value later on. Like I said, this is just my opinion.

Putting all new wire in, is an excellent idea. I cringe when I see restored cars with 50+ year old wiring because it's just an accident waiting to happen. I've used AAW kits in the past and they are excellent quality. I used the Speedway 20 circuit kit on my Blazerhttp://www.speedwaymotors.com/Speedw...ess,42872.html
and it's identical to the AAW kit. Even the instructions are the same. The kit you're looking at is more complete, but is a lot more money too.

[tjsblazer]

Originally Posted by hemi43

Even though I'm using a late model engine in my Blazer, I opted to plug all the firewall holes with proper sized grommets because I was reluctant to do anything to the truck that couldn't be reversed. Just my opinion, but it might be something to think about in case the next owner wants to reverse things back to original. These trucks will only go up in value and you don't want to do something that may hurt it's value later on. Like I said, this is just my opinion.

Putting all new wire in, is an excellent idea. I cringe when I see restored cars with 50+ year old wiring because it's just an accident waiting to happen. I've used AAW kits in the past and they are excellent quality. I used the Speedway 20 circuit kit on my Blazerhttp://www.speedwaymotors.com/Speedw...ess,42872.html
and it's identical to the AAW kit. Even the instructions are the same. The kit you're looking at is more complete, but is a lot more money too.

Dan, I've gone both ways on the shaving the firewall or not. I don't think I'll ever sell this one, but my mid-year vettes are gone now and I said I'd never sell them either so who knows. I'm not running an LS like you but I have converted over to a modern NV4500 5spd and a built 383 so it isn't exactly stock either. I'm hoping for a stock look from 20 feet away.

I bought the AAW kit a few months ago from a forum member who decided he wasn't going to use it so the price was good (not as good as the speedway you linked).
What source did you use for grommets? Just curious in case.

This AAW kit uses the '68+ firewall junction size so since these trucks are a '67 design you have to enlarge that square hole in the firewall about 1/4" each way. Did you have to do that with the kit you used?

Great info. Cheers.