1950 J.D. M ignition

thanks mel

*********TROUBLESHOOTING*******************

1) First, make sure that theres a hot 12 VOLT wire getting to the BAT terminal on the ignition switch. Use of a test lamp is the easiest. If theres a blown fuse between the source and the switches BAT (input) terminal, she cant work. The path for a hot feed source to the switch is via a wire from the ungrounded battery post, or off a starter terminal,,,,, , possibly to and through a series ammeter,,,,, , possibly a fuse if it has one,,,,, ,,, and then to the switches input, its BAT terminal.

Regardless how it may have been changed or jury rigged over the years, you have to have a hot voltage source wire to the switches BAT terminal input, usually via a fuse or an ammeter depending on whats been changed over the years.

2) Once theres a hot 12 volt source to switches input (BAT terminal), turn the ignition ON and verify that switches hot 12 volts to the IGN output switch terminal. Those switches can go bad and NOT feed voltage to the IGN terminal when switched on.

3) CIRCUIT: The IGN switch output terminal should have a wire to and through that series voltage dropping ballast resistor you added and then down to the coils high input (NOT to distributor) lil terminal.

4) Therefore, place your test lamp on the coils high input (NOT to disributor) terminal, turn the ignition switch ON, and it should light up. IF NOT, trace back per the above steps till you see where it fails, and the reverse path is:

Coils input,,,,, to and through the Ballast,,,,Switches output IGN terminal,,,,, ,Switches input BAT terminal,,,,, ,,to and through any fuse,,,,, possibly to and through an ammeter,,,,, ,to the hot ungrounded battery post, possibly via the starter terminal.

Trace that path down and you may simply have a bad fuse or a bad switch or mis wired form the switch and ballast to the coils input.

Post back or e mail me at [email protected] your findings and any more questions.

Good Luck n God Bless ya Mel

John T Nordhoff

~If you DO have power at the [BAT] terminal on the ign switch, then turn the switch on & see if you have 12 volts on the [IGN] terminal of the ignition switch, if you DON'T have power there but DO at the [BAT] terminal, then your ignition switch is probably bad [probably a corroded or oxidized internal contact].. That ignition switch can be taken apart & cleaned but it is a pain.. [high resistance in those M ignition switches is a somewhat common problem also]..

~If you Do have power at both the [BAT] & [IGN] terminals on the ignition switch then suspect an open wire between the ignition switch's [IGN] terminal & that resistor you installed..

~Now to make it easier to understand, here is the power flow on that ignition circuit.... 12 volt power flows from the battery's non grounded post to the starter's big stud, power then flows from the big starter's stud to the ammeter's battery side,, then from the ammeter's non battery side THROUGH the dash fuse to the [BAT] terminal on the ignition switch,, then out through the ignition switch's [IGN] terminal to your installed ballast resistor,, then from the resistor to the coils NON distributor side..

~Post back or E-Mail with any questions.. It's a pretty simple circuit so you shouldn't have any problems finding the open..

[email protected]