Low voltage to accessories from ignition switch

[Wakeboarder141]

1990 Bayliner Capri 4.3

I have a 3 wire ignition switch that is getting 12.7V to the switch on the battery wire, but only putting out 11.9V on the purple accessory wire. I noticed it because the voltage gauge on the dash was reading under 12V all the time. Does that just mean the switch is bad? Do I need to replace it with a particular switch or will any of the 3 wire switches I see for sale work as long as the dimensions look right? Thanks!

 

[alldodge]

That's quite a bit of drop thru a switch IF that is whats happening. All the boat gauges can be off. Might be on the ground side, even at the engine connector

That said, you can replace the switch with any 3 position switch

 

[Wakeboarder141]

That's quite a bit of drop thru a switch IF that is whats happening. All the boat gauges can be off. Might be on the ground side, even at the engine connector

That said, you can replace the switch with any 3 position switch

I am checking with a multi-meter at the switch terminals, so it's not in the gauges. Is there a different way I should be checking?

 

[alldodge]

Your checking it correctly, just saying if the ground or the hot going to the 10 pin connector is corroded, it would skew the reading. If you can connect to the battery neg for ground, you could determine it its on the ground side

 

[Wakeboarder141]

Your checking it correctly, just saying if the ground or the hot going to the 10 pin connector is corroded, it would skew the reading. If you can connect to the battery neg for ground, you could determine it its on the ground side

Even though the battery cable going to the ignition switch is reading 12.7 properly? Since the accessory terminal on the switch is where the voltage is being lost, in my brain that says it is a problem internally with the switch unless I am missing something. 12.7 going into the switch, 11.9 coming out.

 

[alldodge]

Agree, its just sometimes it just might be something else, and checking back to the bat may very well be a waste

 

[alldodge]

Also assuming that both measurements are taken at the same time, key ON and not running

 

[Wakeboarder141]

Also assuming that both measurements are taken at the same time, key ON and not running

Yes, that is how I tested it. 30 year old, easily replaceable $20 part so easy enough to confirm.

 

[poconojoe]

Your readings should be good as long as your using the same ground point for your tester's ground lead for testing both positive points.

 

[sam am I]

Could be the contacts in the switch worn and corroded and/or with the given amount of current through those contacts, voltage drop can increase.........I'm so cheap, I've taken many apart of the years and either re-surfaced them, flip them over if possible or purchased replacement contacts. They do wear out............

V (drop)=I (circuit)*R (contact)

When I and/or R goes up, V goes........

 

[Wakeboarder141]

I ordered a new switch, and will report back with my results. Thanks!