Wiper wiring

[Cyberplod]

Just completing full rewire on motor cruiser - previous wiring was like an explosion in a multi coloured spaghetti factory with most cables spliced to random coloured leftovers!

Only remaining issue is the wiper motor. It is a Simpson Lawrence unit with three wires, colours are unlikely to be originals, but are black/red, purple and red.

Any advice on proper connection would be gratefully accepted, before I attack it with a combination of a multimeter and guesswork. Even the principle of the three wire system would be appreciated.

Steve

 

[VicS]

If it is a self parking one
One will be the negative. Of the other two one will be a permanently live positive that will allow it to run after the switch is turned off until it reaches the parking position. The other will be the connection to the switch.

If it is in its parked position you'll get a continuity between the latter and negative but not between the former and negative. If it is not in the parked position you'll get continuity between all three. A low resistance to the negative and zero between the other two.

If its not self parking then is it a two speed unit? Nothing to suggest if that's what it is.

 

[Billjratt]

You will have a constant live to the internal parking switch, a switched live, or a switch in parallel with the parking switch and a negative. If you take off the cover - you might as well grease and check them anyway, you will see the simple switch and everything will be obvious. Curiously, mine have the switches in the negative line, but either will do.

 

[Cyberplod]

Many thanks - can't wait to get over to the boat and try it out!

Steve