New screen washer pump assembly only has 2 terminals

Technical advice Q&A

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PhilBell
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#1 New screen washer pump assembly only has 2 terminals

Post by PhilBell » Wed Oct 06, 2021 12:28 pm

My new original-style screen washer pump assembly from SNGB has two terminals, the old one had 3. To add to my confusion, the previous owner fitted an auxiliary pump behind the glove box instead of fixing or replacing the original.
When I connect just two of the original pump wires to the new washer bottle-mounted one, the pump springs into action and squirts the screen as soon as I turn the ignition on. The auxiliary pump, still in place, springs into action when I flick th washer switch, though fails to pump any liquid, hence my buying a new original-style one. It's also leaking.
Thoughts?
Phil
1962 FHC 885626

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Allrand
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#2 Re: New screen washer pump assembly only has 2 terminals

Post by Allrand » Wed Oct 06, 2021 4:05 pm

All 3.8's had a 3 terminal pump, you'll have to get a wiring diagram for the 2 terminal pump, or get a 3 terminal pump. Seems your pump isn't wired through the switch.
Randall Botha
'64 3.8 fhc & '51 Mk 7 (now sold)

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265bhp
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#3 Re: New screen washer pump assembly only has 2 terminals

Post by 265bhp » Wed Oct 06, 2021 8:10 pm

Phil
I don’t know whether this will truly answer your question but I had a similar issue as I have used a new 2 wire pump housed within the lid of my original pump

You don’t need the black wire from the loom

The green/black and green are all you need

Hope that helps
Jonathan
1963 3.8 FHC ..now finished …………….
1974 2.7 Carrera now as an RS Touring

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PhilBell
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#4 Re: New screen washer pump assembly only has 2 terminals

Post by PhilBell » Fri Oct 08, 2021 11:55 pm

Although your solution didn't work at first because of the supplementary wiring added by the previous owner for an auxiliary pump hidden behind the glovebox, once I'd removed that extra wiring and reconnected the original circuit, your suggested connections worked perfectly. So you set me off in the right direction. Thank you. Otherwise I might have still been battling with it now.
Phil
1962 FHC 885626

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Heuer
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#5 Re: New screen washer pump assembly only has 2 terminals

Post by Heuer » Sat Oct 09, 2021 9:34 am

The original 2SJ Screenjet was designed to continue pumping after a momentary flick of the switch, for a set time To do this it required three wires, switched live, permanent live and earth. It was a notoriously unreliable system! You can read about it in detail in the 3.8 Factory Fit thread.
https://forum.etypeuk.com/viewtopic.php?p=34931#p34931

In your case you have probably connected the permanent live wire instead of the switched live. A multimeter should confirm.
David Jones
S1 OTS OSB
1997 Porsche 911 Guards Red
2024 Lexus LBX

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