66 Under Dash Wiring Help

[66Throttle]

I need some help from a wiring guru on a 66 convertible, standard interior. For my wiring, I was fortunate enough (note sarcasm) to have to replace the entire cowl assembly allowing perfect access to replace all the under dash wiring. Even though I have numerous wiring diagrams, I laid the new harness out and labeled, numbered and described location and color on each wire on the new harness as I removed the old wire from its original position.

Enough history, here is my dilemma. I have extra wires on the new harness that weren’t on my original harness and some I haven’t been able to identify because they weren’t originally used. Going through all the wiring diagrams I could find, I was able to identify some of them as a pair of wires for the FULL console and a fog lamp wire with an eye on the end. I have neither option on this Mustang so I used heat shrink to cap them off.

The wires I have left over are:

• Solid white wire coming out of harness with the fuse block. This isn’t the solid white jumper from the wiper switch. The solid white from the wiper switch originally went into a black with red stripe wire that had three female inputs. Should the white wiper jumper go to the solid white on the harness?

• Two wires joined into a right angle spade female Red with white stripe, Blue with white stripe
• Single wire with right angle spade female, white w\Red stripe
• Large rubber connector with four wires White w\Blue, Light green\white stripe, White w\red stripe and lastly dark green.

I thought these were for the emergency flasher but the flasher and emergency flasher switch both go into a separate harness that wires between the main harness and loops to the cigarette lighter post for power. The one I’m most concerned with is the solid white wire next to the fuse block. The others I ass-u-me are for extra equipment that mine doesn’t come with stock. As I said, everything went back exactly as I took the old one off.

ANY help is much appreciated.

Photos of the project can be seen here. Index of /rossnae

 

[BarnStang]

I'm going to make a guess, cause I don't see this on any diagram as you well know. THe windshiled wiper WASHER feed was a white wire with a fuse holder that went to the back of the ign switch on the ACC post. THen it went to the wiper switch, and the lead from the washer pump went to the wiper switch, when you pull the wiper knob, it connected these two wires and the pump runs. (just did all this on a 65 and my 66 at home) I am going to bet that you can connect the washer pump power wire to this white wire rather than to the ACC post, and I would also consider that the pump pwer wire does not go to the plug you have it connected to. It will work, but it's not the original connection. Check the whiite wire with your test light and see if you have 12v there with the key in ACC or ON.

The other stuff I cannot find in the diagram. THe two wires in a right angle connector almost have to be a flasher, but one behind the inst cluster, one near the center under the bottom of the dash. WHere is the two wire right angle plug at?

THe only white/red strip wire I know if is the oil pressure sender wire...not sure why that would have a spade terminal on it. THe 68 Shelby did some funney stuff with that wire to put a gauge in the console...

Have you put power to the system yet? anything not working?


Where is the rubber connector with 4 wires at? ALmost sounds like the backup lights/neutral safety switch plug, but the wire colors are way wrong...

 

[66Throttle]

I really appreciate the reply.

It’s gotta be pump related because that’s the only solid white I could find on the diagrams so I’ll follow your lead and undo the washer wire on the switch until I get to the point of supplying power and play with it. There’s never a guarantee that the original pump wiring was 100% correct because my uncle had it forty two years before me.

On the two right angle spades, they along with the rubber connector come out of the harness along with the yellow resistor wire by the air box. I too thought it was flasher wiring. That being said...

One of my flashers will eventually attach to the clip on the air vent outlet on driver side when I put the cowl back on. That one is wired correct per the diagrams and color codes and location of the one I removed.

The other flasher fits the lower dash clip next to the glove box for my emergency warning. My emergency warning switch and flasher are on a separate harness that jumps between the main harness and the steering column connectors and the wiring colors are correct per the diagrams.

I got the harness from CJ Ponyparts, attached is the photo they use and I’ve illustrated the wires. I just checked ands the harness I received is the harness they sell as the 66

One more note, in looking at an AC switch on NPD, I can’t see the back too well, but maybe this rubber connector fits an AC switch.

 

[Capt Dan]

the big one looks like a flasher plug to me.



View attachment 307158

 

[keithnra]

if i get homw in time tonight ill look at my 66 b/c i have the entire dash out of it right now.It should be fairly simple to see.

 

[BarnStang]

I think Capt Dan got it. Unless that's already hooked up. THe other ones, no idea. but I can see a female bullet connecter on the white wire. I bet you could use that for the washer pump. Worth checking with a test light. I'll look at mine too.

 

[66Throttle]

That’s it. My emergency flasher switch and flasher (see attached photo) has the four wires riveted into the back of the switch and it has its own harness that plugs into the steering column and then to the main harness.

After seeing Capt Dan's photo, the rubber connector and two spade wires must be for the emergency flasher.

I went looking for a different switch so I could eliminate the 40 year old switch harness. I found that they changed to the spades on the emergency switch (C6AZ-13A350-D) in March of 66 so the switch could be serviceable. Mine happens to be September 1965 mfg date so that’s why I had a separate harness. I found a comparatively inexpensive later model switch so I can eliminate the old harness.

On the white wire:
From the engine bay, the washer pump black wire goes into the wiper switch as it should based on all the diagrams. There is a solid white jumper wire coming off the switch that received power from another source on my old harness. I put power to the harness and the pump worked. The white wire on the new harness also supplies power, so I connected the white off the switch to it and the pump still worked. I’ll leave it there so I don’t have a dangling white wire.

Thanks guys for all your help. That’s one major hurdle accomplished. Finally I can mig the new cowl in place.

Progress photos are stored here until I decide what I’m going to load in the gallery.
Index of /rossnae