windshield washer motor

[swedefish]

I`m trying to get my electrical washer motor to work on my Barracuda -67.
But it only runs when I jump a wire from the motor housing to negative ground on the car, and then push the washer button on the dash.
Does any of you guys know how the motor nomally gets its negative ground?
I did check in my service manual, but it didn`t say anything about it.
Many thanks in advance
Len

 

[GTGrinly]

seems to me its grounding off the housing where it is mounted, make sure everything is clean and you have a good metal to metal contact at mounting with no paint in between.

 

[RedFish]

The brown that plugs in is the 12V + . There is a black wire for ground placed under the rearward resivoir mounting screw (nearest to ballast resistor).