my truck wont run with the key in the on postition

[w100 360ci]

i got a 74 dodge 4x4 w 100 once and awhile it wont run with the key in the one postion itll start and die when i let the key back itll run in the gap between where it starts and shuts everything off the radio and everything work in the on postion it just wont run it shuts off and only does that once and ahwile

[75 Power Wagon]

Check the wires going to the ballast resistor.... their is apink and red wires (I cant remember which was which) but one is hot only when in start, and the other is hot only in run.... use a test light, and check to see... Sounds like their is a short in the wire someone... Try to trace it back... also, the ballast resistor might have something messed up with it.

[lebaronman]

My money is on the ballast resistor.

[75 Power Wagon]

Yup, you should be able to test them like i said... and if one of them is hot going into the ballast resistor, then im sure that its the ballast resistor too.

[w100 360ci]

whats the ballest register and where is it located and i took my steering wheel off ahwile ago and check all the conections and clean it all and it hasnt done it since and it did it today when i got outta school

[75 Power Wagon]

The ballast resistor is in the engine compartment... should be on the drivers side fenderwell... It's a little 2prong or 4prong white square shaped thing...

[w100 360ci]

ya i havnt checked it but i doubt its that cause when i bought the truck i was at my dads and he had a new one in his garage and i was like what the hell and put it on and plus would it work somtimes and sometimes not

[bherder]

Maybe ignition switch.

[75 Power Wagon]

those ballast resistors are very prone to problems... I would at least do that check that i was telling you (see if theres one hot wire going into it in the run position, and a hot wire on the other end leaving it to the ignition) If this works, then you can rule out the ballast resistor. It's one of the most common things, and is pretty simple to check. Next thing would be tracing the wire back (free)... and then replacing the ignition switch.

[lebaronman]

75 power wagon's advice is right on the money.

[bherder]

ya i havnt checked it but i doubt its that cause when i bought the truck i was at my dads and he had a new one in his garage and i was like what the hell and put it on and plus would it work somtimes and sometimes not

Ballast resistors (Or "ballest register" as you say) in my experience either work or they don't. I've yet to see one that 'sometimes' worked. Doesn't mean it can't happen I suppose, but I've never seen it.. ;)
If you say it works most of the time and at other times you have to kinda' tweek the key between positions and then it runs.. I'd be looking at the ignition switch, connector and/or the wiring. You also want to check the bulkhead on the firewall.. that the connections are clean and it solidly plugged in.

(Just so you know, when you start your truck, when you're cranking it, the ignition switch is by-passing the ballast resistor. You're getting full voltage to the coil. When you let off the key to the 'run' position, the ignition switch routes the voltage to the coil through the ballast resistor, which drops the voltage to 9-10 volts... something like that...
If the ballast resistor fries, it won't start/run at all.. Back in the day, unless you had a retro-fit hi-performance ignition system, you usually kept a spare resistor in the glove box. It was cheap insurance that you didn't get stuck 100 miles from home.. ;) )

[Ram3500Dually]

Back in the day, unless you had a retro-fit hi-performance ignition system, you usually kept a spare resistor in the glove box. It was cheap insurance that you didn't get stuck 100 miles from home.. ;) )

Back in the day I used to keep a couple of them in my glove box. Anytime I heard a chryco start and shut off I walked over and "fixed" it for them for $20 bucks. It was a very common problem in the 70's/early 80's

[Dodgevanman]

I kept a spare ECU in the glove box as well. Any vintage Mopar survival kit has these parts in it.

[bherder]

I kept a spare ECU in the glove box as well. Any vintage Mopar survival kit has these parts in it.

Hey Nate, that's one of the beauties of my GM HEI conversion... If anything should ever go buns-up, being as I left the Mopar ECU bolted to the firewall and the ballast resistor now lives in my glove box... And it would take me about 5 minutes to switch it back to original...

I've got a built-in backup ignition! Just like NASCAR :D

[Slug-Gunner]

Ballast resistors (Or "ballest register" as you say) in my experience either work or they don't. I've yet to see one that 'sometimes' worked. Doesn't mean it can't happen I suppose, but I've never seen it.. ;)

Well, I had one go "intermittant" on me. It happened during the cold hunting season. It would start/run when the outside temps were cold, but once the engine warmed up the engine compartment, it would "cut-off" the engine and not restart. :help: When it would try to "start", but not "run" when you let off the key, I knew right where to look. Luckily, I always carried the "spare" ballast resistor and ECU in the glove box.... and once I figured it out and changed it out, we're back on the road again. :D

[w100 360ci]

the thing is how am i supposed to check it if its working right now...should i just wait till it does it again....another thing my brake lights dont work everythink else works perfect...and my boss has the same prob on his 76 ramcharger and he says its like the turnsignal assembly inside the steering colum and none of my dash likes work any suggestions there...

[Speed Dragon]

If it's intermittent, I'd check the bulkhead connector in the firewall, then the grounds, then the switch.