I havent looked at the back of my switch to count the terminals, but yes, our 66 with single speed wipers has washers. The pumps are different between the single and two speed systems. The pump on single speed wipers has one wire and is grounded to its mount where the two speed pump is a two wire set-up. I'll be converting to two speed and will use a 65 harnes that will let me use the one wire pump.

 

My 66 has one speed wipers with pump. Build date January 66. However the pump itself is disconnected and I've never bothered to look at the switch or wires for it.

 

Thank you for your reply. I was fairly certain that '66's with one speed wipers could come with a pump - what adds to the confusion is that I understand that there were 2 versions of the pump - one with 2 wires and one with 1 wire.

But if anyone can confirm or deny how either one of the pump types (either 1 wire or 2 wire) connected to the wiper switch with a one-speed wiper (and motor), I would greatly appreciate it. All wiring diagrams I can find only show 2-speed wipers connecting to a washer pump.

I have the 5 wire harness as shown in the above wire diagram going to a one-speed wiper switch going to the motor, but I have a 7 terminal switch. How does a pump connect to a one-speed wiper motor?

 

Thank you for your reply. I was fairly certain that '66's with one speed wipers could come with a pump - what adds to the confusion is that I understand that there were 2 versions of the pump - one with 2 wires and one with 1 wire.

But if anyone can confirm or deny how either one of the pump types (either 1 wire or 2 wire) connected to the wiper switch with a one-speed wiper (and motor), I would greatly appreciate it. All wiring diagrams I can find only show 2-speed wipers connecting to a washer pump.

View attachment 819351

I have the 5 wire harness as shown in the above wire diagram going to a one-speed wiper switch going to the motor, but I have a 7 terminal switch. How does a pump connect to a one-speed wiper motor?
The single speed washer has three bolts that hold it on the inner fender, the two speed has two. I have a single wire that runs for the pump two the switch. I can look deeper into it if need me to.

 

BW,

My car came with the earlier style pump with 3 bolts that attached it to the inner fender that was probably not original on my car. It was not hooked up to anything.

If you have a single-speed wiper with 7 terminals with one of the terminals running to the pump, I would be curious how it is hooked up.

Thanks for the reply.

 

At the switch you should have a 5-wire plug. Then I have a single wire that runs to the pump and that plugs into one of the other terminals. I tried to look, but I can't see it. But if you plug your 5- wire plug in and hit the washer and put a tester on the other 2 terminals you can tell which one is for the washer.

 

My car has the early style pump and it's a 66.

 

BW,

To confirm what you are saying, you have an early style pump (with one wire) that feeds into one of the 7 terminals at the wiper switch, correct? And 5 of the 7 terminals comprises the wiper wire harness over to the wiper motor, correct? Which leaves one open/unused terminal at the wiper switch, correct?

 

Yes one wire pump. Yes, Feeds into one of the 7 terminals at the switch. Yes, 5 of the terminals are used for the wiper motor. I was wrong about the last one it's part of the pump harness and feeds the pump shown in the picture below. (Sorry it was a long time ago) For more info. look at the following NPD Part #'s wiper switch 17A553-2,

Harness part # 17B587-1A and Washer harness part # 17A622-1A

 

IIRC if you wanted a 2 speed wiper in 66, it was an option. Part of what I think was called " visual safety package ".
Included 2 speed, plus think day/night rear view mirror.. Been awhile since I've read up.
My 66 vert came single but already have correct wiper switch and motor harness to upgrade. Haven't done resto on car yet

 

@sixtysevenGTconv is barking up the right tree.
The Visibility Group was an option package with the two-speed wiper with washer, day / nite mirror, remote driver mirror, and if I recall correctly the banded windshield.
I converted my 66 with single speed wipers and washer to the two-speed wiper and washer with the correct switch, motor (which bolted right up to the same mounting bracket), underdash harness, the underhood harness to the washer, and the washer pump. The underhood harness will work with either pump I believe, but I wanted the correct one and I got an NOS one on ebay. If I recall the 2 speed switch has 7 terminals.

 

Thanks everyone. And thanks BW, that picture is useful - I have never seen it before.

It is beginning to make sense based on the diagram except for the connections after the 958 (white) wire connection leaves the wiper switch. Can you tell me what that connection is at "C"? I cannot figure out what is happening in between "C" and the "Splice in Main Wiring Assy." Not sure that I have 297A black-green wire or anything connected at the fuse panel that is then routed back into the main wiring assembly.

 

If you look at the three NPD part #'s I gave you that might also help. There was someone on this forum that rebuilt wiring harnesses. I went with new, but I heard he does a great job. If I can help you with anything more let me know. That picture is from one of the Jim Osborn assembly manuals, they are very helpful.

 

Single speed with pump here. Mid April '66 build date.

 

I have the "Dave Graham" manuals - I think they are similar. The assembly manuals are helpful to a point.

I have emailed Randy at Midlife Wire Harness to see if he had any suggestions but I haven't heard back from him. I think I need to either rebuild the harness via Midlife or get a new one thru NPD. However, it is very expensive and Scott at NPD warned that I might end up chasing more rabbits down rabbit holes trying to get it to work in the car. I think he said there were like 6 different versions of the underdash wiring harnesses in 66.

 

BW - you said you went with new. I meant to ask what harness you went with. NPD OEM style or did you go with the upgraded version with more modern wiring? I would like to make the plunge and get the new harness, but at $500 and no return policy on electrical parts it makes me queasy.

 

I went with the OEM style. I replaced the whole thing. The biggest problem I had was the dash light sockets, not a good fit. (Loose)

 

Did you have any issues getting everything to tie into together? Like tying back into the wiring for the rear lights, etc.? I wish they listed what all is included in the main underdash wiring harness. Don't know if it includes wiring for the courtesy light, emergency flashers, etc. I asked if they had a list of what is included and they say they didn't. For example, does it include all the connections for accessories such as fog lamps, ac, etc. if wanted to be added in the future?

 

Make sure you match any harness to the month and year your car was built. I had no issues getting everything together. It has the Ford feed for all the accessories, but if those accessories have a harness that does not come with it. This is the main harness, it does have four-way flashers and the under the dash courtesy light sockets.

 

FYI, in `66 two speed wipers were a $12.95 regular production option. For $29.81 the visibility group included remote control mirror,, day/night mirror AND two speed wipers.

 

Yes and yes. If you need a 1-speed with washer switch I have a spare you can have for just the postage.

 

PM sent

 

Damn, missed out! Need one myself.

 

I have a '66 (Nov '65 build) and the car has a 1 speed wiper system with the washer that grounds to the body (apron). And, it works now that I have completely re-wired the car for safety and function. If I recall, the positive washer wire, runs from a switch terminal thru the firewall to the washer.

I rewired the car with OEM spec stuff made by Alloy Metal Products (USA Made-sold by NPD) and couldn't be happier with the result. All the colors & connectors were right. Some will prefer aftermarket choices for more electrical options and amperage, but I have no intent to install a fancy infortainment system in the car. If I wanted all that, I'd buy a newer car...

I will say, that there are more than enough build variations to make anyone a bit crazy, on these cars...

If your Mustang has the original wiring in it, its past time to fix that for safety sake.

 

I know this is a month old, but I felt it necessary to share if anyone ever has this issue. Thanks to Randy Jacobson with Midlife Harness Restoration, I would still be pulling out my hair without him.

To reiterate, I have a '66 with an original single-speed wiper switch with seven terminals (same as NPD #17A553-2), a single-speed wiper harness (NPD #17B587-1A), a one-speed wiper motor, and the original early style/one-wire washer pump (same as NPD #17664-1B). Five of the seven terminals on the wiper switch are occupied by the wiper harness from the switch to the wiper motor. Of course, the previous owner(s) messed with the under-dash wiring, and I did not have any feed wire connection from the wiper switch to the pump. There is only one wiring diagram that I have seen that somewhat accurately describes the setup I have. Online searches and wiring diagrams never fully described my setup and were lacking details. It seems as if this setup was a mystery. Shout out to user BW66 for sharing this wiring diagram last month.

However, after discussions with Randy, I finally got a resolution. My biggest issue was how the white wire for the feed wire connection (NPD #17A622-1A) connected. The black-white wire of the feed connection was pretty obvious - one end to the pump spade terminal and one end to one of the two remaining terminal spade connections on the wiper switch. The white wire end with a spade connector is plugged into the wiper switch's last terminal spade connection. However, the other end of the white wire with a male bullet connector was a mystery. From what was described to me by Randy, the white wire “mystery” end can be the following:

For '65's - the white wire end was designed to connect to the ignition switch back post using a ringed connector.
In '66 - they changed the white wire to a male bullet connector for the one-speed wiper. There should be a white wire with a molded female connector around where all the wires from the turn signals mate. This female connector is tied to a fused ACC line (from the fuse box).

However, what threw me for a loop in my case was that I didn't have any type of ringed connector off of the ignition switch back post (not a ’65), and I also did not have a molded female connector around the turn signal mating area. So, Randy threw me a lifeline and told me that in my case, the white wire end with the male connector should plug into a three-prong plug coming from the fuse box (this plug also connects the neutral safety switch wiring/black-red #140). I made a quick test connection as described by Randy, and the darn pump came to life. I probably should have figured it out if I were halfway competent at car wiring... As Randy described to me, it appears that my car experienced a change-over from early to late '66 wiring. That is what contributed to the confusion. I also asked him if it was correct that the three-pronged connector tied to the 14 amp fuse in the fuse panel from the front rather than the rear. He told me that early '66 had the ACC extension on the front of the fuse box and the later version had it coming out of the backside of the fuse panel.

I know this is a super long post, but I tried to make it as detailed as possible because surely someone will be in the same position as I was and ready to give up on it. Thanks again to all the users who responded to my post last month, especially BW66. And, of course, a million thanks to Randy. I will send in my harness to him as soon as possible to get it rehabbed.