Ignition Switch Short

Doug (OH) · Nov 8, 2010

Hi all, I rewired my '55 Ford 640 during the summer. The tractor was previously wired for an automobile style switch, bypassing the push button by the shifter and it has been converted to 12V. It snowed. Tractor got wet. I put in a freshly charged battery (which I was charging up for winter anyway) and the darn thing cranked slow, then I notice smoke coming out of the hood.At least three of the wires at the switch were having a melt down.(I did not skimp on wire guage when I rewired.) I have a newer solenoid with the push button on it. Used that instead with the ignition key on. Cranked great and started. Any ideas where the short is coming from? Thanks, you guys always give great advice!

JMOR · Nov 8, 2010

(quoted from post at 20:51:12 11/08/10) Hi all, I rewired my '55 Ford 640 during the summer. The tractor was previously wired for an automobile style switch, bypassing the push button by the shifter and it has been converted to 12V. It snowed. Tractor got wet. I put in a freshly charged battery (which I was charging up for winter anyway) and the darn thing cranked slow, then I notice smoke coming out of the hood.At least three of the wires at the switch were having a melt down.(I did not skimp on wire guage when I rewired.) I have a newer solenoid with the push button on it. Used that instead with the ignition key on. Cranked great and started. Any ideas where the short is coming from? Thanks, you guys always give great advice!

ollow the wire that burned.

souNdguy · Nov 8, 2010

the oem thumbswitch 3 terminal interlocked solenoids are not the same as a new key-start solenoid.

we'd have to see your wire diagram.

but as jmor said. look at the burning wires and see where the go..

soundguy

Doug (OH) · Nov 9, 2010

Thanks, I will send that to you tonight.

souNdguy · Nov 9, 2010

post em here so we can all take a look. 2+ heads are bettern' 1.

soundguy

Doug (OH) · Nov 9, 2010

Hi again, here is the wiring diagram I used. Pretty sure I found it on this site. I added the red wire because w/o it the solenoid buzzed while cranking (even tho it started). With the wire the buzzing stopped and it was cranking fine. Thanks for checking it out. Doug

souNdguy · Nov 9, 2010

well.. looks like you have the starter wired right to the + side of the amp gauge.

what did you expenct that to do? the starter is a high current device...

no wonder you have burnt wires...

soundguy

Doug (OH) · Nov 9, 2010

OK. Why does the relay buzz/vibrate the button on it without the wire? Thanks (electrically challenged).

souNdguy · Nov 9, 2010

hard to guess. bad relay, wrong relay.. bad wireing TO relay. take your pic. I had a buzzing relay on my 740 when I got it.. wrong relay wired up realy.realy weird..

if you use the thumb switch I reccomend an OE realy. if you are stuck on a key to start auto realy.. get that style... though I don't reccomend them.

soundguy

Doug (OH) · Nov 9, 2010

I'm thinking I want to go back to the starter button (thumb button?) by the shifter. Not stuck on the auto style ignition switch--just came that way. I see the light (er, spark) now. Thanks. Now I'm a little less electrically challenged

souNdguy · Nov 10, 2010

yep, your wireing effectively bypassed the solenoid and was attempting to power the starter thru that lil wire.

get the oem solenoid, and use the thumb switch. it's a much better / safer deal.

soundguy

souNdguy · Nov 10, 2010

i'd for sure reccomend it.

soundguy

Ignition Switch Short

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