Help with wire locations

[blacktj01]

Hi, I need some help with the location of where wires go through the firewall for a '77 K20.

What I need to know is:

1. backup switch for the 4 speed
2. Tachometer
3. Power Window
4. Aux battery

I know that I can pretty much drill holes any place I want to but what fun would that be? Their are bumps in the firewall where holes should be so if someone could get me close that would be great.


Thanks
Rob

[blacktj01]

nobody knows ware the holes for the wires should be?

[87Bob]

Sorry mines an 85. I could check it when I get home Friday and let you know where mine are.

[blacktj01]

Originally Posted by 87Bob

Sorry mines an 85. I could check it when I get home Friday and let you know where mine are.

Thank you any help would be great

Rob

[87Bob]

I have a Chevy truck manual at home, I am on the road right know so I can't check it. I'll see if there are any pictures in it that show anything you have asked about. If they do I'll post pictures this week end.

[87Bob]

The book I have is an 82 but here is what I have found so far.

http://i38.photobucket.com/albums/e1...pwiring002.jpg

I know it's not all you asked for but it is a start. It looks like most of the wiring comes through the firewall just below the wiper motor

[Captkaos]

All of the wiring for the backup switch will come out of the fusebox.
I honestly don't remember where the tach lead comes out, but I believe it was the fusebox also
The Dual battery won't go through the firewall
The Power window don't go through it either, they go though the door frame.
Plows were not installed on them by GM, so if you think it came from where you have it pictured, I would use it.

I think the oil line is correct, but not 100% sure, the one labeled dual tanks is wrong.

[87Bob]

Originally Posted by Captkaos

All of the wiring for the backup switch will come out of the fusebox.
I honestly don't remember where the tach lead comes out, but I believe it was the fusebox also
The Dual battery won't go through the firewall
The Power window don't go through it either, they go though the door frame.
Plows were not installed on them by GM, so if you think it came from where you have it pictured, I would use it.

I think the oil line is correct, but not 100% sure, the one labeled dual tanks is wrong.

Ah the Captain come through yet again (You da man!)

[blacktj01]

Originally Posted by Captkaos

All of the wiring for the backup switch will come out of the fusebox.
I honestly don't remember where the tach lead comes out, but I believe it was the fusebox also
The Dual battery won't go through the firewall
The Power window don't go through it either, they go though the door frame.
Plows were not installed on them by GM, so if you think it came from where you have it pictured, I would use it.

I think the oil line is correct, but not 100% sure, the one labeled dual tanks is wrong.

For the backup switch, I have the harness and it has the grommet to go through the firewall and an adapter to hook up inside the cab to the wire harness for the automatic backup switch. I will post a pic shortly.

In '77 and '78 the power window power came from the junction box under the hood with a 30 amp circuit breaker. The power lead has a grommet to go through the firewall.

The plow I put on, I was just pointing out what the holes are for my reference.

And the one for dual tanks, now I am really confused as that is the only hole in the other cab I have it could possibly fit?

This would all be so much easer if the guy who "restored the cab" did the job correct. I have the whole cab stripped down to get sand blasted so I can not even test fit things to get an idea where they go now. And I would like to drill the holes before primer and paint

Thank you for your help

Rob

[blacktj01]

87BOB what book is that? I really like the detail that it gives

Rob

[87Bob]

Originally Posted by blacktj01

87BOB what book is that? I really like the detail that it gives

Rob

It's the 82 Chevy shop manual. Need something else let me know I'll try to find it and shoot a picture of it.

[blacktj01]

Here is the wire for the backup switch

The grey end goes to the transmission and the black end goes in the cab
Rob