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Little wiring help

1K views 20 replies 8 participants last post by  wveddy 
#1 ·
So chasing some wiring gremlins from and older wiring hack job. Ended up ripping out the complete under dash harness to replace it. Quick question though. there is a 2 wire with male/female connectors running to the automatic shifter. i know it is for the light on the shifter. wiring diagram shows 1 wire and just grounding by the shifter. my guess is the second wire is a ground. but looking for advice from wiring gurus. these wires were not connected in my mess, so no frame of reference. appreciate any help.
 
#5 ·
This is a great site to learn how to understand and solve electrical issues.


Go there, look at the diagrams and schematics, and try and discover the wiring issues. Before there were sites like vintage-mustang, all of us used these paper illustrations to solve our issues. Let us know how you do.
 
#7 ·
Schematic Font Material property Parallel Technical drawing


(click below for larger)
Trans selector indicator light - upper right.
19 BLU/RED switched power
57 BLK ground
 

Attachments

#12 ·
they are black with red stripes. in the wiring diagram that would be reverse sensor wires for a manual. not a console car.

View attachment 854187
That was going to be my second suggestion but you said it had an automatic, so the console lights were more likely. So apparently at one point in its life the car had a manual transmission. IIRC, the wires go up the hump to the firewall pad, go behind the pad and back out where they plug into the main harness. It should be removable.
 
#10 ·
i’m not sure these wires are even supposed to be in here. :rolleyes:
Anyway, i replaced the neutral safety wiring and switch. And rewiring to the shifter light with a nee wire. See if that works. The color diagrams are way easier to follow than black and white.
 
#11 ·
Ended up ripping out the complete under dash harness to replace it.
Are those wires part of the replacement harness? Where did you get the replacement?
 
#15 · (Edited)
agree, but its an automatic. backup lights should fire from the neutral safety switch. My speculation is someone tried to hot wire the backup lights to the auto shifter at one point. the neutral safety switch and wiring was completely removed. goes without saying the backup lights have never worked. Fixing all that, so might work now.👍🏻
 
#14 ·
Making progress on my rewire. Lotta work to just play buzzy 8tracks louder. 😂. Just utterly amazing how sloppy people can be on wiring, which if i am not mistaken is the number 1 fire cause in old cars. Bad connections, nothing water tight, sloppy wire routing. argh 😠. If only my wire loop wraps would show up. be looking good 👍🏻
Motor vehicle Car Automotive exterior Vehicle Gas
 
#16 ·
Need some wire identification help. been digging through the wiring diagram and still can’t figure these out.

My guess is emergency flashers. But literally nothing on my car or thr old harness matches this.

the plug and other two wires are under the glovebox area near the passenger side of the car.

Automotive lighting Light Automotive tire Electrical wiring Gas
 
#17 ·
Emergency Flasher switch and relay. In 65 it was a separate add on harness. Some 66 cars have the switch built in to the harness. Others like your new one have a plug and removable switch.
 
#18 ·
So the big plug goes to the switch other two flat plugs go on the flasher? wire colors don’t match the diagram, but i had a flasher in about the same location on the old harness. I also found what i think was the old switch harness, broken and taped up.
 
#19 ·
Yes that is correct and I compared the wire colors to an original 66 harness and they match. the diagram was likely for the earlier harness with the non integral flasher.
 
#20 ·
Really just be easier if the damn harness came with its own diagram. The diagrams are by “system” and not by “harness”. Just make it easier like painless labeling the wires.

Thanks for the quick responses. Hugely helpful getting validation on wiring. And all this to be able to play 8tracks louder 🤣.
 
#21 ·
Underdash harness in and tested.
Underhood engine harness in and tested.
Neutral safety wiring in.
Really only the headlight and taillight wiring left to do. Also replace speedo cable while i was at it. Everything appears to working. Only issue is the amp gauge dancing. As others have found, the main harness plugs don’t seem to go all the way together, but they work. I did have to splice and make a few connectors from the old harnesses. Big lesson on mixing wiring vendors, really surprised how connectors from different vendors dont work together. Hopefully car is much safer with all the new wiring.
Still working on tidying up the wiring, but looks way better too.

Motor vehicle Hood Automotive lighting Bumper Automotive tire

Motor vehicle Hood Automotive design Automotive exterior Car
 
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