The Triumph Dolomite Club - Discussion Forum

Can anyone help with a electrical problem.dolomite sprint 1977. All electrics work except windscreen washer pump. Pump will work when connected directly to battery. Live feed to pump fine. Connect feed to pump still reading live. As soon as earth terminal is connected no live. Same if direct earth from battery. Would appreciate any advice thanks Nick.

Good question; I detect you are using a very sensitive electronic voltmeter to do the measurement. The reason you are seeing 12V at the pump with the earth disconnected is that you have some very small current leakage across the switch contacts just from dust and dirt and moisture in the air . It is quite dull and damp down in the South of the U.K. this week. The reason this voltage disappears when you connect the earth lead is that this very small current runs down to earth.
I did the same measurement on my 1850 today and I got 350mV with the Ignition ON and a 10Mohm DVM with the earth lead disconnected.
Anyway from the good measurements you have done the motor is O.K. the earth is O.K. which leaves the switch contacts on the end of the steering column stalk. I think this just prises off and you can then get to the copper contacts, clean them up and away you go.
HTH,
Tony.

Had come to a similar conclusion. Will try this weekend. Thanks for reply