I have had this old boy for 34 years and after finding the correct assembly decided to replace the aftermarket screenwasher setup with the correct Lucas 5SJ unit. The PO had cut the plug off the LightGreenBlack and Black wires that originally went to the top of the Lucas washer/pump. The LGB wire was run to one spade on the aftermarket pump. Somewhere in the engine compt, a black wire Y was spliced in. with one "leg" of the black wire going to the other spade connector on the washer pump. The other 'leg' was grounded with a loop under one of the screws on the washer's bracket. This aftermarket pump did run when the dash switch was pressed, holding the switch down made the pump spray until you released the switch. I read somewhere on some other E forum that the 5SJ would spray 3 times once the washer switch on the dash was pressed. Is this correct? This same post indicated that if that pump motor was grounded, the pump would only spray as long as the switch was held down. I don't mind how the washer works, so is it OK to just reconnect the wires to the new 5SJ? or should I redo the wiring and put it back the way it left factory? I don't have the plug, and I doubt I would be able to find that original style plug, so I would put on spade/Lucar connectors. I do have the Bentley manual with all the elect diagrams. The wiring is correct on the back of dash switch.. LGB is positive. The new 5SJ unit has its terminals marked + and -. Just don't want to ruin an expensive new part.

 

Still working on this and did find some OLD posts on this very topic. Interestingly enough, not through a forum search, but just general Google:

jjbunn
Feb '11
In reply to a message from jjbunn sent Fri 18 Feb 2011:

Well, I often find that soon after posting to the forum, I
find the answer myself - must be the process of thinking it
through before posting.

Anyway, this proved to be very simple: a missing ground wire
for the washer pump. I’m not sure what had happened to the
original (where did it get grounded), but adding a new one
resulted in a working washer and windscreen wiper.–
Julian, '69 E-Type 2+2

and also

outonJerry Mouton
Jan '04
Javier,

The original setup had a Rube Goldberg setup to keep the
washer going for a while after you let the switch off, and
the third wire (black) is a ground wire for that function.
Don’t connect the black wire.

The green wire is hot (12v) and the light green with black wire
goes to the dashboard switch, which connects to ground when
lifted. Connect those two to the washer, and try it both ways –
one way it may pump better. Not sure whether the motor
reverses or not.

Jerry

The green wire is -12v on a pos ground car and the light green/black wire goes to the dash
I believe, is that
there is supposed to be an automatic time out so the pump will run for a
few seconds when you tap the switch on the original set up.

*********************

So now at least I have a better understanding of how that Washer switch and the motor/pump work. Will reconnect it all today and see what happens.

 

Reconnected everything.. two wires to 5SJ and the ground and pressed the washer switch... some anemic shots of WS fluid, but at least it functions.

 

Sounds like it's back to just like new!

 

Thank you and I thought so ,too. But now I realize the washer assembly was put together backwards. The spade connectors should face the bulkhead, with the fill cap facing outboard. This fill cap faces outboard, but wiring connectors face engine.

 

Well, user-confusion for the week. Went to my Brit Club carsNcoffee this am and checked another 69. While I thought the lid had threads, and so would not change its position, it turned out the bottle has notches that correspond to nibs on the cap and cap was easily rotated to correct position.