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Discussion Starter · #1 ·
I have looked and seen there are many threads re wiring for a washer pump, my question is slightly different.
SO,,I have just purchased a 66 coupe with no washer pump or hoses etc. I brought a kit to install the washer jets and all the water hoses etc. I had a small modern washer pump on the shelf so am intending using that. There is no wiring adjacent to the pump, but up near the firewall close to the brake master cylinder I found this (see photo). I have tested the two wires from the duo plug, and one of them does become live when you pull the wiper switch. The other half of the plug does not appear to be an earth. There is also a third chopped off wire close to the plug (photo). This third wire may be nothing to do with the washers of course. Can anybody shed any light please ?
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1966 Mustang 289/306 3spd coupe, 1966 Mustang 289 C4 coupe, 1965/64.5 Mustang 289 4spd convertible
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That two prong plug is indeed the washer pump harness end. The W/P extension is available reproduction, as well as the washer pump if you decide to keep it factory. They're not terribly expensive. I could be wrong but I believe the pump is earthed through the pump mounting screws. If I remember after work I can look at my wiring schematic or at my '66 and possibly find out what the chopped red wire is unless someone beats me to it.
 

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Discussion Starter · #4 ·
That would be great, thank you. So you are both saying that the duo plug are live and earth for the pump. Trouble is the live seems intermittent, and the earth does not seem to earth. I am wondering if the switch is dirty and not working properly ?
 

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'66 Convertible 200/c4 Vintage Inline Headers with Arvinode Duals
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Do you have two speed wipers? The single speed wipers have a single wire to the pump which is grounded to the fender. Dual speed wipers have two wires to the pump.
 

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'66 Convertible 200/c4 Vintage Inline Headers with Arvinode Duals
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I have 2 speed wipers, but am trying to use a modern off the shelf pump.
Use the hot wire from the switch to connect to the pump and ground like a single speed setup. Its not "correct" but it'll work.
 

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1966 Mustang 289/306 3spd coupe, 1966 Mustang 289 C4 coupe, 1965/64.5 Mustang 289 4spd convertible
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Wow...that's a new one to me. Thanks.
Thanks to the age of texting, a lot of acronyms out there now. Use to just be military guys. Americans in general use them quite often.

I only get slightly annoyed when some are spoken. When one says LOL out loud, shouldn't they just be laughing?

Other spoken acronyms make sense spoken when in polite company. FUBAR or SNAFU for example.
 

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1966 Mustang 289/306 3spd coupe, 1966 Mustang 289 C4 coupe, 1965/64.5 Mustang 289 4spd convertible
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That would be great, thank you. So you are both saying that the duo plug are live and earth for the pump. Trouble is the live seems intermittent, and the earth does not seem to earth. I am wondering if the switch is dirty and not working properly ?
My thoughts on this are both are switched hot, just different pathways from the switch depending on the wiper speed, the earth/ground is when the pump is screwed to the inner fender which is part of the body, thus earthed/ground by the body ground from the battery. (I could be mistaken)
 

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1966 Mustang 289/306 3spd coupe, 1966 Mustang 289 C4 coupe, 1965/64.5 Mustang 289 4spd convertible
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^ to test this theory, you could use either a Volt meter earthed/grounded at the pump must location, or a test light hooked to the pump location. Then use the hot probe on each terminal of the duo connecter with the switch on speed one, then on speed two to see if you get voltage or a light.
 

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The washer function for the 2-speed wiper, IIRC, cycled with the motion of the wipers.
I have factory type 2 speed wipers, and pulling the knob straight out when the wipers are on or off will activate the pump. The two speeds are slow and really slow. :ROFLMAO:
 

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1966 Mustang 289/306 3spd coupe, 1966 Mustang 289 C4 coupe, 1965/64.5 Mustang 289 4spd convertible
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I have factory type 2 speed wipers, and pulling the knob straight out when the wipers are on or off will activate the pump. The two speeds are slow and really slow. :ROFLMAO:
Still beats the vacuum wipers on my '54, you could control the speed with your right foot. As you accelerated, vacuum to the wipers was decreased, and they would slow or just plain stop. I didn't use them often so I never bothered looking into it.
 

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Looking at the 1966 wiring diagrams, one wire should be live coming from the wiper switch when the washer pump is being activated. The other is earth (ground) coming from the wiper motor and to the washer pump. The wire coming from the switch to the two prong connector is Black/White. That will be your live wire.

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Discussion Starter · #18 ·
^ to test this theory, you could use either a Volt meter earthed/grounded at the pump must location, or a test light hooked to the pump location. Then use the hot probe on each terminal of the duo connecter with the switch on speed one, then on speed two to see if you get voltage or a light.
That's a good idea, I will try that. I have a 12v test probe with a bulb. SO if they both happen to be live...which one should I use ? or does it not matter. BUT if they are both lives (HOT when switched) wouldn't they both be insulated at plug, instead of just the one ?
 

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Discussion Starter · #19 ·
Looking at the 1966 wiring diagrams, one wire should be live coming from the wiper switch when the washer pump is being activated. The other is earth (ground) coming from the wiper motor and to the washer pump. The wire coming from the switch to the two prong connector is Black/White. That will be your live wire.

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That's brilliant, thank you so much. I suspected that if one pin of the plug was live then the other would be a ground. I will have another look tomorrow.
 

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66 two speed wipers ground at the wiper motor through a set of contacts. It uses a different style of pump and squirts by the on/off cycle of the contacts. To use your "modern" pump, use the wiring harness "hot" wire then ground the pump to the pump mounting bolt. The wiring harness ground back to the wiper motor will be unused.
 
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