Do I need a diode?

[Green72]

1967 GTX Hellcat swap. I need to accomplish 1 and 2 to complete my wiring. I have the yellow wire from Ignition switch (cranking only power) connected as needed in number 1. Number 2 requires power at cranking and in run position. If I tie into the yellow wire for power when cranking and tie into a wire that is on in the run position I will end up with power all the time on number 1. Can I install a diode to keep the power off number 1 when in run position? I know almost nothing about diodes so if i correct please let me know what diode to get. Ignore the circled paragraph.
Geeeezzz I hope that makes sense.

 

[pnora]

No diode needed. 1 is crank only has nothing to do with ignition. 2 is power to ignition when key is on and while cranking, nothing to do with the actual starter cranking.. Are you using the 67 ignition switch?

 

[pnora]

If you are using the factory ignition switch , 1 the crank only would go to the yellow wire S2-18-Y. 2 The ignition power when on and while cranking you will need to tie the J2-16-DBL and J3-14-BR together .

 

[Green72]

I am using factory ignition switch.

 

[pnora]

I am using factory ignition switch.

Then what I said in Post 3 should work.

 

[Green72]

Ok that's what I thought. But I'm confused because neither of the wires DBL or BR show any power when I turn key to crank position?

 

[RemCharger]

Ok that's what I thought. But I'm confused because neither of the wires DBL or BR show any power when I turn key to crank position?

Then there's a problem with the switch/wiring / bulkhead etc. Time to see why.

 

[Nacho-RT74]

BDL gets power with key in RUN (ign1)
BR gets power while cranking (START or Ign2) to bypass the ballast

However when ballast is conected, it splices the power all around on both sides and wires, but a diff voltage level depending on which wire gets hot from ign key.

If needing full 12 volts on both stages ( Start and Run) there are several options depending on your goal:
-modify wiring splicing both circuits together to run one single circuit at any point between ignition key and ballast.
-jumper wire between ballast resistor terminals
-modify ballast resistor replacing resistor with a jumper wire into the rear groove… mainly to keep stock clean look.

As mentioned, yellow wire to starter motor relay gets power just while cranking to serve just the starter motor function.

(These changed on 75 and laters models)

 

[451Mopar]

As mentioned, the two wires at the ballast resistor, usually Brown (key start position), and Blue (key run position) are connected together. The Yellow (key start position) should be left as stock to the starter neutral safety relay.
If the condition of the stock switch and wiring have high resistance or intermittent contacts it will create problems.
I am using the Brown/Blue wires to trigger a 30 Amp optocoupler relay through diodes with a 220+ uF Capacitor on the trigger side of the relay to get good clean power and prevent intermittent dropouts if the key power drops for less than a second. I wired the relay board to self-energize, so there is no parasitic drain when the key is off.

 

[Green72]

Thanks everyone!! I figured it out. It’s amazing what a night of sleep can do for you

 

[Sixpactogo]

I tied the start and run wires together on my build. It worked about 2 out of 3 times but when it failed, the Hemi would flutter and miss. My switch must have been worn or something. Chris at Hotwire told me the Hemi can sense that break in continuity between start and run and will let you know. I have no idea how it could sense a break when the two wires are tied together but I ended up adding a push button for the start and no longer have that issue.

 

[Don Frelier]

I tied the start and run wires together on my build. It worked about 2 out of 3 times but when it failed, the Hemi would flutter and miss. My switch must have been worn or something. Chris at Hotwire told me the Hemi can sense that break in continuity between start and run and will let you know. I have no idea how it could sense a break when the two wires are tied together but I ended up adding a push button for the start and no longer have that issue.

View attachment 1988859

It's a function of the ignition switch.
When rotating from run towards crank there's a window where the run contact opens and the start contact is not yet closed. so for a few milliseconds depending on how fast you turn the key there is 0v at the 2 wires. This could likely vary between switches

 

[Sixpactogo]

It's a function of the ignition switch.
When rotating from run towards crank there's a window where the run contact opens and the start contact is not yet closed. so for a few milliseconds depending on how fast you turn the key there is 0v at the 2 wires. This could likely vary between switches

That makes sense. That was why I tied the two wires together at the switch hoping there would be no break. It helped but I guess my switch found the zero volts.

 

[Green72]

Interesting
I hope I don’t have that issue