| FAQ |
| Members List |
| Social Groups |
| Calendar |
| Search |
| Today's Posts |
|
#1
02-18-2025, 09:24 PM
|
|||
|
|||
Mystery Brown Wire Coming From Firewall On '66 GTO
I've looked at every wiring diagram I can find and I can't find where the single brown wire coming out of the grommet on the far left side of the firewall goes. it looks factory and has a broken off end on it.
|
|
#2
02-18-2025, 09:45 PM
|
||||
|
||||
|
Blower motor?
__________________
" Is wearing a helmet illegal" Mike Kerr 1-29-09 |
|
#3
02-18-2025, 09:51 PM
|
||||
|
||||
|
Tachometer Lead? Not normally shown on the diagrams
__________________
Ed 1968 GTO (Thanks Mom) 2006 Silverado 2007 Cadillac SRX 2015 Chevy Express  2024 Cadillac LYRIQ 
|
|
#4
02-18-2025, 10:41 PM
|
||||
|
||||
|
Far left side as in driver side?
I'd go with the tach wire also. 
__________________
John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
|
#5
02-18-2025, 11:04 PM
|
|||
|
|||
|
Yes drivers side. the blower motor is already hooked up.
Could be tach, it has factory rally gauge. the length would be about right. I already have 2 wires going to the coil in the harness, but I haven't started the engine yet so I'm not sure if the tach is wired in. it did work before the restoration. |
|
#6
02-19-2025, 02:03 AM
|
||||
|
||||
|
Then it may be missing the fuse section.
__________________
Ed 1968 GTO (Thanks Mom) 2006 Silverado 2007 Cadillac SRX 2015 Chevy Express 2024 Cadillac LYRIQ
|
|
#7
02-20-2025, 10:26 PM
|
|||
|
|||
|
On my 64, with upgraded disc brakes and an Autowire harness, there is a brown wire in that area that goes down to the brake warning light switch on the proportioning valve.
|
|
#8
02-20-2025, 11:17 PM
|
|||
|
|||
|
This is all original so it never had a proportioning valve.
It comes out of an odd looking gromet on the far left drivers' side. it's definitely factor wiring. I guess when I get it running if the tach doesn't work I could try it there. |
|
#9
02-21-2025, 01:49 AM
|
||||
|
||||
|
It's definitely tach wire. See '66 shop manual pic below.
|
|
#10
02-21-2025, 11:54 AM
|
|||
|
|||
|
Thank you, it seems like it should be in the harness but it is what it is.
|
|
#11
02-21-2025, 12:18 PM
|
||||
|
||||
|
From what I've seen, optional equipment usually had their own harness and I understand the logic behind that. Reduces the cost of additional wire(s) or the number of different harnesses.
__________________
Ed 1968 GTO (Thanks Mom) 2006 Silverado 2007 Cadillac SRX 2015 Chevy Express 2024 Cadillac LYRIQ
|
| Reply |
| Thread Tools | |
| Display Modes | |
|
|
The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.
Linear Mode
