How can I identify ignition switch terminals for my ride-on mower? I bought a 5-terminal, 3-position ignition switch for my ride-on, to replace one in which the key got broken off. Terminals on the original were marked B-G-S-M-L, but the replacement is marked B-A-I-R-S, and I can't match these to the wiring diagram in the owners manual. I've already blown a fuse five times, trying first to match up with the corresponding positions on the original switch and then swapping them around.

Aussie Mike, December 2008

why dont you get a small needlenose pliers and pull the broken key out and get a new key.

jon, December 2008

The answer above should be right fore your old switch. Useing a ohm meter hook one lead to B termal and the other lead to the S termal turn the switch to the start postion see if you get reading. If you do the S termal goes to one side of the solenoid. With one lead still on the B termal and the other lead on the I termal and the switch in the normal run postion see if you have a reading on the meter. If so you can use I termal to your lights and so on Check the remaining two termals With the meter lead hooked to B termal and the switch in the run postion if you get a reading on the meter you can not ground any termal. Allso try see if there is any reading with the switch in the off position. With out a separt ground you will not be kill the motor which would hook to your mag. You can not apply batery to the mag
Useing the ohms scale on the meter requires a dry circit meaning no wires are hooked to the switch when testing Use X1k scale on the meter short the meter leads together to make sure the meter is working. The meter should read full scale. Good luck!

Larry Craig, December 2008

Seems I was sold a switch for a coil ignition - not magneto - and although it looks the same, the internal wiring is different. Have since got hold of the correct switch and everything is working fine again. Fortunately no damage done.

Michael, December 2008

OK watch this space - I will see what I can dig up regarding the strange terminal ID's. Is the switch definitely from a magneto-ignition tractor? I've never seen those markings before.

phil_saunders@bigfoot.com

Phil Saunders, December 2008

Thanks Phil, but I think the postage to Australia might be a bit steep! I wouldn't need to butcher the wiring - the wires are not on a terminal block, they are all fitted with separate spade connectors, and are matched to the BGSM terminals as you describe. I just need to know which wire to connect to which BAIRS lettered terminal, before I blow any more fuses!

Aussie Mike, December 2008

You have the wrong switch. I can supply the correct one for £12.50 +P&P.

In my opinion, it's not worth butchering the wiring to make the wrong switch work, but if you want to persist ;-

On your original switch ;-

B - Battery (via fuse)
G - Ground
S - Starter Solenoid (probably via several safety switches - connects to 'B' when switch at 'START')
M - Magneto (connects to 'G' when 'off')
L - Load (connects to 'B' when 'on')

You will have to meter out your new switch and swap the connections around n the connector block to match. It is entirely possible that the new switch will not provide the right combination (eg you may find that the lights only work when the starter's engaged or whatever).

BE SURE YOU DO NOT APPLY BATTERY VOLTAGE TO THE MAGNETO.

phil_saunders@bigfoot.com

Phil Saunders, December 2008