# Ignition switch wiring



## MichaelJenny (Dec 21, 2008)

Hi!

Michael from Australia here - just joined and hope someone can help me with this problem. The terminals on the ignition switch of my ride-on mower (Tecumseh 12.5hp Enduro engine) are marked S-M-L-G-B. This switch is now useless because the key broke inside it, so I got another 5-terminal switch to replace it. However, the terminals on this are marked B-A-I-R-S and I need to know which of these relates to the terminals on the old switch. I guess the B and S terminals are the same, but how would I match the others to the appropriate wires? The wires are not on a terminal block, they are all fitted with separate spade connectors, so I just need to know which wire to connect to which lettered terminal, before I blow any more fuses! 

The two switches look identical, but obviously they are wired differently internally. Any ideas?

Thanks.


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## paulr44 (Oct 14, 2008)

S-M-L-G-B = starter-magneto-lights-ground-battery

The new switch "A" terminal should be the same as the "L" term. on the new one, and *most likely* the "R" terminal is the same as the "S" terminal. You'll have to use an ohmmeter and test the new switch terminals in various key positions to be sure.

S-when turned to "start" sends power to the starter solenoid.
M-when turned to "off" grounds the ign. coil.
L-lights / accessories
G-ground
B-battery

What you absolutely must do, is test the new switch "I" terminal. The old switch was wired for a magneto, which when rotated to the "off" position connected "G" to "I," grounding it out. The new switch possibly may send power to the "I" terminal when the switch is in the "Run" position. If you send power to a magneto coil, it'll smoke it (burn it up, instantly).


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## MichaelJenny (Dec 21, 2008)

*Wrong switch*

Thanks, Paul. You're right about the BAIRS one being wired for a coil, while the mower uses magneto ignition. My local "expert" who sold it me on the basis that it had the same number of terminals in the same position obviously needs to do some homework! I don't want to risk doing any damage to the magneto so I'll go get the correct switch and hope I can get a refund on the wrong one! Thanks again for your detailed reply.


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## paulr44 (Oct 14, 2008)

We use Oregon and Stens keyswitches for most homeowner-unit applications - they work fine, and aren't too pricey. Run from like $12 to $25 U.S. Don't know if either sell in Australia though.
Good luck!
Paul


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## MichaelJenny (Dec 21, 2008)

*Fixed!*

Managed to get the correct switch from another local dealer for $45AUD (about the same as $25US), and ride-on is now going fine. Another learning experience!


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