Thorneycroft 2.5 diesel starter switch wiring

[AOWYN]

Does anybody have a diagram for wiring the starter switch for a Thorneycroft 2.5 diesel. The present unit has 5 terminals on the back, all of which are in use. I have what I thought was a spare, but it only has four terminals and I think that a diagram might be a good idea before I try to experiment while lying under the cockpit floor.
Thanks in advance

 

[tazzle]

Depends on the polarity of your system and alternator to some extent. But if you have a standard positive non-insulated earth return leccy system with an alternator with integral regulator it's pretty straightforward.

Some diesel switches come with paired spade connectors - 10mm and 6mm lucar - on the 'feed' and 'run' terminals. Ignoring the pairs, 4 terminals will probably be supply - run - heat - start, 5 terminals supply - aux - run - heat - start.

About 5 mts with a £5 megger will tell you which ones.

If you have the room, it may be a good time to install a small bus bar or two fed from a decent say 8mm2 connection from the spare 'run' terminal.

Also never underestimate the current taken by the glow plugs - this can be 30 amps on a BMC block.

There are some useful manuals thoughtfully provided by a nice NL guy at Populaire Scheepsmotoren - try under BMC for Thorneycroft

 

[AOWYN]

Thanks for help.

I'll have to find out what the spare fifth terminal is connected to and see if it can just be doubled onto the "run" terminal.
Wish me luck.

B