Topic: 1966 Wiper Pump Wiring through the firewall - Oct San Jose

[jstefanick]

I have done my due diligence, researched the sources I know, and the sometimes accurate Osborn drawings and I seem to have run into a dead end. I have the single speed wiper pump on my 66 convertible, it is an approx. Oct 18, 1965 build, San Jose car.

While doing some long overdue engine work and freshen up of the engine compartment, I remembered I never addressed the hole in the firewall that I had seen for a couple of years. My wiper pump single wire is routed through the firewall, but the hole mine goes through is BELOW the main harness plug, not through the currently empty hole above the main harness. I remember the 66 coupe Metuchen car that I owned with single speed wipers and pump seemed to have a bigger rubber plug with the single wire going through the firewall in that empty hole on my firewall. I thought that was the standard setup.

To make things interesting, I got a shot from inside of the car of this "alternate" wiper pump wire through my firewall. The hole looks very much like it was stamped there, as any other hole would be. And, the grommet fits just fine.

I figured I must have some oddball thing a previous owner did, so I bought a single wire wiper pump harness from NPD, figuring I would properly route my wiper pump wiring through the bigger hole, the rubber grommet in the NPD kit, at least online, looked to be what I needed size wise. 

Sure enough, I get the NPD wiper pump single wire feed today, and the rubber grommet that goes through the firewall is the same small size as what I have currently in the car.

I am confused now, I always thought the wiper pump wire went through the firewall at the bigger upper hole, and now I have a replacement kit and an possible original wire in the car with a pretty small rubber grommet that would in no way be able to fill that bigger hole.

I took some reference pics, along with a pic of the two rubber grommet sizes I am talking about. The bigger grommet I got from some old back up light wiring I had, and that happens to be the exact size of the hole in my firewall. (it will make a perfect plug in case I need it).There is also a smaller punched hole to the left of the bigger hole, which I believe may be for a firewall pad pin?

I have made notes on each pic, which I think make my question easier to understand.


I know this hole in my firewall has NOT been added in by someone and is in other cars. What in the world should be routed though there, or is this another plant difference in early 66 cars of how they routed wiring and I should simply plug the hole up?

[J_Speegle]

Maybe we should start out with how your car is equipped

So far we have a San Jose 66   V8?   Oct built fastback? with what transmission?

Non-GT?  Automatic?

Maybe that will help weed out some examples that do not relate to your question since my quick look shows examples with no hole (identified by you as a washer wire hole) below the main Junction block. 

[jstefanick]

The car in question is a 66 - 6 cylinder - 3 speed manual- with single speed wipers and one wire pump. San Jose build - 18K- 6R08T120933

[J_Speegle]

The car in question is a 66 - 6 cylinder - 3 speed manual- with single speed wipers and one wire pump. San Jose build - 18K- 6R08T120933

Thanks helps formulate/find an answer much easier

It looks like the hole you have above the headlight (and other things) electrical junction block likely had a rubber plug (whole not used) for  car with your options and equipment as in the picture below. Have a number of other examples with the same rubber plug. Firewall changed and hole usage did also after your production date - the reason those details are important

Plug appears to be the same shape as those used with the radio delete option that covered the antenna hole in the passenger side cowl face under the fender. Flat wide, raised edge with a flat center surface








As far as the up most hole that you have label as a possible firewall pad retainer I don't believe that hole is there for that purpose. Still looking for another example with a hole in that location. Will continue and report back Might be PO added

Different application shows another larger hole and wire passing through (green arrow) where your unused hole is located (more to the outside edge of the car) but the car is very different in options and details though the same time period

As you can see no firewall pad pin in the location as yours

[jstefanick]

Thank you for your "Library of Mustangs" collections search of pics relavent to my car. That is a tough spot to get reference pics to look at, being so close to the edge of the inner fender/firewall, not many are taking pics of that, thankfully you were able to dig some up.

I think the pics you found support me putting in that larger plug I have in the hole above the harness  plug (I will clean it up and snip out the wires before doing do, it will fit fine)

I think also, from the pics, it appears that the wiper pump wire, at least on mine and others in my approx build date/location, motor/options- is going under the main harness plug, so I now have confidence that I dont need to re-do the wiper pump wiring, the smaller hole under the main harness looks to be used for the wiper pump wire, at least on my particular car.

I thought my 66 Metuchen coupe, V8, Non GT, D2 4/2/66 approx date, used that top bigger hole with the larger grommet for the wiper pump- I am pretty sure my memory is good on that. Perhaps they changed what they used that hole for as the model year continued, as you suggest. I wonder what that hole was used for typically?

In regards to the possibliity of the other hole to the left of the larger hole in my firewall being a possible location for a dash pad pin, it certainly is possible a previous owner punched it in. But, the shape and style of that hole looks like the other dash pad pin punched holes in my firewall. I think in that first picture, you can see it right below the export brace, a little black dot, it looks alot like what I have.

Thanks again, the info you provide I use to make these decisions and know it will be right.

[J_Speegle]

I thought my 66 Metuchen coupe, V8, Non GT, D2 4/2/66 approx date, used that top bigger hole with the larger grommet for the wiper pump- I am pretty sure my memory is good on that. Perhaps they changed what they used that hole for as the model year continued, as you suggest. I wonder what that hole was used for typically?

Different car, year and plant. Apples and Oranges it appears after looking at examples related to the car we're focusing on - the Oct 65 built San Jose.

In regards to the possibility of the other hole to the left of the larger hole in my firewall being a possible location for a dash pad pin, it certainly is possible a previous owner punched it in. But, the shape and style of that hole looks like the other dash pad pin punched holes in my firewall. I think in that first picture, you can see it right below the export brace, a little black dot, it looks allot like what I have.

Consider that the pin locations was not random for the firewall pad. Each had a specific hole already punched through the material what matched a punched hole in the firewall made when that panel was formed. So if one car had one at a specific location then all should (with in reason and a given production period)

With that said I offer the following  examples that are easier to view in that area. Notice no holes in the spot where your car has one. we punch through holes for alarms, radios, stereos and many other things. Examples from the 110000-150000 period

















This one has what might be a hole in the same location (one out of now 8 examples) but it was not used and sealed over if it is there

[mjd 65]

I took a quick shot of my July 65 Metuchen coupe's wiring in that area.  The washer wiring is above the headlight harness. The open hole is for the firewall pad.

[J_Speegle]

I took a quick shot of my July 65 Metuchen coupe's wiring in that area.  The washer wiring is above the headlight harness. The open hole is for the firewall pad.

Different year and plant  than the focus for the thread

Apparently there were changes between the two production periods

Possibly different firewall pad also

[mustang6er]

Thought i should throw my .02 in, first pic '66, SJ, 6cyl, 07B,  (feb 7 66) build, the washer pump wiring below the connector, second pic, '66 SJ was originally a 6cyl, a 28D, (april 28 66) build, the washer pump wiring came through the topside of the connector (when it was original) no hole or plug under the connector.
Good luck.

[jwc66k]

I just looked at my 66 San Jose GT Fastback with the same build date, 18K (a Monday), and the top hole on mine is for a two speed washer, then the rectangle connector, with the fog lights cable below that. There is no additional plug.
A possible scenario: the two speed cable contains two wires, which may require a larger hole to accommodate a larger grommet. I am assuming that because the single speed washers were standard equipment and the hole would be pre-punched on all 66 models. If the hole was punched for a two speed wiper on a car without that requirement, the correct size hole would be punched elsewhere, and without a fog light requirement, that would be the next best spot. A plug would be used to cover the enlarged hole.
Jim

[J_Speegle]

Thought i should throw my .02 in, first pic '66, SJ, 6cyl, 07B,  (feb 7 66) build, the washer pump wiring below the connector, second pic, '66 SJ was originally a 6cyl, a 28D, (april 28 66) build, the washer pump wiring came through the topside of the connector (when it was original) no hole or plug under the connector.
Good luck.

That matches what I found - depends on when the car was built and what options