6 Terminal Ignition Switch Query

[pcmpete]

I am rewiring my project boat. The ignition switch has 6 terminals. I can figure out what 5 of them are, but the sixth one I have no idea what is for.
Terminals:
30 - 12v power supply
30 - 12v power output
75 - Accessory
15 - Ignition
50 - Starter
57a - ??????????

57a gets power when the key is turned all the way back and key out. What function(s) would use this 57a terminal and why?

 

[Texasmark]

Re: 6 Terminal Ignition Switch Query

Assuming you mean power and not ground. To be ground it could be ignition kill, course removal of 12v from wire 15 ought to do that. It could be voltage to a fuel enrichment valve (non fuel injected Merc) but that requires you to push in on the key to get voltage to that valve (choking substitute for mechanical butterflies.....you didn't say what engine this was for).

I can understand your confusion if the terminal is supplied with 12v via the switch internal contacts when you turn the key off. One would think that when the key is off, all power is off; one would think.

Dunno

Mark

 

[a70eliminator]

Re: 6 Terminal Ignition Switch Query

Full time power supply to a bilge pump relay?

 

[ENSIGN]

Re: 6 Terminal Ignition Switch Query

Sounds like a accessory terminal for when the engine is turned off.

 

[Mark_VTfisherman]

Re: 6 Terminal Ignition Switch Query

I don't know everything and don't know your boat. I am assuming that your ignition switch is on the dash of your boat, and the choke is either manual or activated by a switch on your helm controls.

I am also assuming your switch is a three-position: off-on-start You *could* have Accessory-off-on-start four-position switch but it's unclear. Usually the key is only removable in the "off" position on either, and ignit switches are made that have an off-position switched power lead.

However, the off-position power switch (57a) is often not connected/utilized and other times it is wired to the anchor light switch and/or cabin convenience lighting. Most often it is unused. Don't know about other purposes. That is my thought based on the assumptions above.

 

[pcmpete]

Re: 6 Terminal Ignition Switch Query

Thanks for all your replies. Yes it is a 4 position switch.
Off / Accessory / Ignition / Start

It is on a Volvo Penta but I don't think the switch is original.

It is unclear what the 57a terminal is for so I will leave it blank (for now)

Thanks for your help and have a happy holiday.