Ignition switch

[41husk]

I have a 70 Duster 318 car.  It will start right up but dies as soon as you let go off the ignition switch.  I was hoping it was the starter relay ( easy to get to) but that did nothing.  I am thinking it is the switch itself in the colum.  Any thoughts?

[70 sublime]

What about the resistor on the firewall ?
Does not the key bypass it and send 12 volts to coil to get it to start then in run position in goes through resistor
If the resistor is burnt out it will stop running ?? 

[41husk]

Yes sir, thank you.  I will at least try the $5 resistor out in the open on the firewall first.  I carry a extra in the charger.

[Nacho-RT74]

before replace the resistor you can make a simple test...

IS YOUR BRAKE LIGHT AT CLUSTER DIMMING WHILE CRANKING ? ( emergency brake applied of course )

if dims out, the ballast is good.

if turns off while cranking, ballast COULD be damaged, but also related wiring, not allways the ballast is damaged. You can get a contact fail on bulkhead too

Then begin to trace the damage with a test light

test light at + lead of coil checking for voltage on both ign switch stages ( unplug the yellow wire at starter relay to not crank the starter motor, no need for that ). Should get dimmed in RUN full light while cranking

if missed the dimmed light on RUN at + lead of coil AND the brake light is also missed while cranking, it is definitelly the ballast or related wires

[Nacho-RT74]

OH... and if brake light doesn't light up on RUN, the fail is on ign switch plug or switch itself

[41husk]

failed switch   gotta pull the wheel and change the switch.

[Nacho-RT74]

seems to be then a Blue wire on ign switch harness failure then ? check the plug down the column. This wire allong with the red one uses to get overheated and miss the connection at plug... sometimes also the black one ( accesories ). Maybe is not the switch but the plug. These switches are really hard to beat

then you can get the new switch and try it before remove everything. Switch doesn't need to be installed on column to start the engine. Just conecting down the column is enough... I mean, just in case.