5 spade terminal ignition switch

tarnoki · Aug 6, 2004

A novice electrical question...
Anyone know what the letters next to each spade correspond to? I'm replacing switch that's currently in the tractor, but wires were already pulled. Case 448 tractor.
Thanks,
Steve

Molerj · Aug 6, 2004

Let me see, B= battery S=solenoid M= magneto G=ground
L=lights A=accesories. I'm sure there is other letters too. What are the 5 letters on your switch?

MicroPilot · Aug 6, 2004

( Let me see, B= battery S=solenoid M= magneto G=ground
L=lights A=accesories. I'm sure there is other letters too. )
/forums/images/graemlins/grin.gif

( What are the 5 letters on your switch? )

Better would be a picture!

BB_TX · Aug 6, 2004

but wires were already pulled /forums/images/graemlins/shocked.gif
If you were not the one who pulled them, or if you don't remember which ones you took off where, then you will probably need a schematic for your tractor to figure out how to replace them. Otherwise you might burn something up, short something out, or otherwise do harm to your system. /forums/images/graemlins/frown.gif

Junkman · Aug 6, 2004

Many switches look alike at both ends, but are internally wired differently. If you use the wrong switch, the results are disastrous. I know because I made this mistake once. I followed the letters on both switches and matched them to each other. Problem was that the switch wasn't wired the same on the inside as the old one. Hope that this is clear to you, but I don't know how else to explain it. Get the correct switch and get a wiring schematic so you know that it is done correctly. That is why many ignition switches have a wire harness plastic terminal end.... so you can't mess up the wiring... Good luck, you certainly are going to need it for this job. I don't envy you in this situation. One small mistake, and "up in smoke".... Cheech and Chong... /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

AndyM · Aug 7, 2004

Get the correct switch and get a wiring schematic so you know that it is done correctly... Good luck, you certainly are going to need it for this job. I don't envy you in this situation. One small mistake, and "up in smoke". 

I would add if the correct switch isn't available and use end up using a generic one, post a picture of the end of it, along with the letters next to each of the terminals, and let someone who is experienced at this sort of thing help you.

I've been there, done that one the "up in smoke" thing (not the Cheech and Chong part). I had a Ford Courier truck I bought for $100 that had no key. It ran fine with the jumper wires I made to start it until I bought one of the generic switches at the auto parts store, made ONE wrong connection with one of the wires, and melted several wires--
I had six wires going into the old one and the new switch only had five terminals. I put the sixth wire where I THOUGHT it should go (bad idea). I also ended up replacing points, coil, and starter. /forums/images/graemlins/mad.gif /forums/images/graemlins/crazy.gif

I rewired the Ford 8N from the mess of spaghetti that was on there, and there's several people here who helped me with it last year, along with wiring diagrams available on the internet.

tarnoki · Aug 7, 2004

( Let me see, B= battery S=solenoid M= magneto G=ground
L=lights A=accesories. I'm sure there is other letters too. What are the 5 letters on your switch?
)

The letters on the switch are S, I, A, R, B.
I should clarify that wired were pulled off switch, but still in the tractor, thus I can trace back to origins.

TWINKLE_TOES · Aug 7, 2004

tarnoki, Welcome to TBN /forums/images/graemlins/cool.gifunless someone comes along and athoritatively states they understand the wiring on your Case 448, and can identify the source and destination of each wire, I would not accept any guesses. The consequences of misswiring an ignition switch can be dramatic (burned up wiring/fire). I would look to your Case dealer for help.

Also:

Case Forum

Soundguy · Aug 8, 2004

( I would add if the correct switch isn't available and use end up using a generic one, p )

I'll add to this advice. A 10 dollar ohm meter will make this an easy task.. especially if the guy has a schematic.. or at least knows what the wires hanging go to already. Use the ohm meter to find out what each terminal does in each position on the generic switch.. then hook up the wires accordingly.

Soundguy

Junkman · Aug 8, 2004

Walter has made some good points..... /forums/images/graemlins/shocked.gif /forums/images/graemlins/crazy.gif /forums/images/graemlins/shocked.gif /forums/images/graemlins/crazy.gif /forums/images/graemlins/shocked.gif /forums/images/graemlins/crazy.gif

While you are in the R & R mood, purchase a new plastic end terminal harness. They cost about $10 and when you figure out what wire goes where, splice it into the replacement harness end. Once you do this, you will never have to deal with loose wires again. It is common for them to be missing, because when the switch fails, it gets very hot back there and the plastic melts. Some look at this as a reason not to replace it, but it does save your sanity even in a melted condition. /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Great Picture Walter... /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif