Ignition Switch Changeout

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Sparky1

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I'm wondering if it is possible to change the column ignition switch in my 72 Duster w/340.
It could the issue as it will not fire but, "sometimes"... when I release the switch then it seems like it wants to fire.
I know that I have seen that same issue posted but can't find it.
So, I guess I would like to start with a switch changeout within the column first.
Thanks
 
Yes it is possible. You may want to swap out the keyed tumbler at the same time and even the turn signal switch while you are in there. Be sure to follow the manual or watch a good youtube video. DO NOT hammer on the end of the shaft or steering wheel puller or you will break the injected plastic "pin" on the 2 part collapsible steering column.
 
Most likely not a problem there In the column. It’s a rabbit hunt for nothing.

what ignition system do you have? Does it have a choke and is it set up properly?
 
Sparky1 said:
it will not fire but, "sometimes"... when I release the switch then it seems like it wants to fire.
Click to expand...
Before you start tearing into your column, have you tried replacing the ballast resistor? That is exactly the symptom. One bolt and two plugs and you're done. Under $5 at RockAuto. Also available just about everywhere else.
 
Professor Fate said:
Before you start tearing into your column, have you tried replacing the ballast resistor? That is exactly the symptom. One bolt and two plugs and you're done. Under $5 at RockAuto. Also available just about everywhere else.
Click to expand...
I thought the same thing but with a ballast resistor, it will start and then quit when you let the switch go to run position. Reason being is the ballast is bypassed in crank but current flows through it when you go to run so a bad ballast will kill a started engine. Perhaps the OP was not written correctly? Cause yeah, if it starts and then quits when you let up, thats for sure a ballast.
 
ACME SS said:
I thought the same thing but with a ballast resistor, it will start and then quit when you let the switch go to run position. Reason being is the ballast is bypassed in crank but current flows through it when you go to run so a bad ballast will kill a started engine. Perhaps the OP was not written correctly? Cause yeah, if it starts and then quits when you let up, thats for sure a ballast.
Click to expand...
Duh... You got me!
 
Just jumper the wires together that are on each side of the ballast.. does it start then !?
 
There are several places a problem like this could be, and you should try and chase it down before tearing the column apart.........that is what voltmeters are for

If you don't have one, run over to MyMopar and download a free factory service manual.

ABodyJoe on here has an old thread with photos that show tearing the wheel etc off and changing the switch.

In no particular order........

Could be ignition switch
Or switch connector exiting the steering colum
Poor connections in the bulkhead connector
Or right at the ballast
Or right at the ECU box or possibly even the distributor pickup.
 
Start (pun intended) by connecting your multimeter or even a 12V test lamp from the coil+ terminal to ground

With key in 'run' and engine stopped you should see about 6--10V, it varies.
Turn key to "start" and read meter while cranking engine. Voltage should be very close to "same as battery," that is----if battery sags to say, 11.5 measured at the battery WHEN CRANKING, then the coil + terminal should be so as well

It is important to understand how the ignition switch works. The IGN1 "run" power IS ONLY LIVE in the run position of the key. It goes DEAD during cranking

The ONLY power to start the engine is IGN2 which is hot in the "start" position, and feeds full battery voltage to the coil + side of the ballast.
 
First thing I did was replace the ballast - no help. Would turn over but not fire.
I also think the firewall is not grounded as there were other areas not grounded either.
I'll attempt to ground the firewall to the frame to see if that helps.
The other potential issue are those bulkhead firewall connections.
Was an original 6 cyl automatic and I dropped in a rebuildt 340 & trans, 650 Holly and other chassis improvements
It was all put together in 2010 and has been running great but early this summer - it just decided not to...
 
The ignition switch is very easy to troubleshoot at the connector with a cheapo Harbor Freight voltmeter. If you don't know how to do it, ask and we can walk you through it. It's a 5 minute job that will save you from spending the time and money on swapping the switch, only to find out it's probably not the issue.
 
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