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Bad Ignition Switch?


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I was at the bank and when I came out, the Jeep wouldn't start, but the solenoid would click. Bad battery I think (Optima Red Top 34/78 of unknown history but at least four years old). Call the auto club, and he has a bit of trouble getting it jumped, and runs diagnostics on the battery: Result was even with full voltage (~12.6V), he says that the battery has no cranking amp capacity so it's toast. Gives me the data printout that documents his conclusion. Not being familiar with AGM spiral wound batteries, I figure it could die suddenly, so a new battery is in order.

 

First though, I drive home and swap in a spare fully charged Red Top (another 34/78 that's about seven years old, and starts the M-B just fine). Nada, Jeep still won't start, and this time, after a click or two, turning the key won't even connect the circuitry. So I swap in an Odyssey 680 AGM plate-type, with far less cranking capacity) and the Jeep starts up just fine. Next morning (after leaving a TFT screen on overnight (dummy) Jeep won't start again, but solenoid clicks. I give it an overnight charge, and (at 12.6V) try to fire it up this morning. One click of the solenoid, then back to absolutely nothing each time I turn the key: No radio, no gauges, nothing.

 

Even if the battery(s) were problematic for cranking, I can't figure anything that would cause the total blank symptom except a duff ignition switch. Am I missing something? Some kind of relay or fuse in the circuit? I'm poring through the Haynes manual, but haven't found anything so far.

 

Switch is buried somewhere at the base of the steering column, right?

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With a charged batt does your radio, heater, wipers, lights, etc come on when the key is in the on position? If they don't come on try turning it to the acc position all the way back towards you. If they come on then it is the ignition switch.

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Just went outside and tried it. Everything came on, and I got one click, then nada in any position.

 

But I'm think now that it isn't the switch, as I tried to turn on the TFT screen (wired independently) and no joy there either.

 

So now I'm thinking maybe bad ground But the TFT screen, and a few other accessories, are wired through an auxiliary fuse panel directly to the battery terminals, both Pos and Neg. More searching is in order!

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How would you loose power to the AUX fuse box if it is wired directly to you batt POS and NEG? Sounds like you need a new starter solenoid to me. This happens to me about every 2 months in my truck. Damn POS!

 

Yeah, I just played with it and the screen is back on but nothing from the main circuit. I fiddled with the cable clamps, in case the problem was between the terminal and the clamp, but I couldn't find any resistance anywhere. I'm trying to understand how a bad solenoid could cause the entire truck circuit to go dead. Maybe I should try the headlights next, since they're also not wired through the ignition switch. :dunno:

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Now I'm totally confused. I just went out and turned the lights on; they shined clear & bright at full power. So I figured WTF and tried the key; the panel lit up and the fuel pump charged the manifold. Turned the key and it fired right up without a problem, even with the headlamps on.

 

Now I've got to figure out what could be causing an INTERMITTENT problem. Oh Boy! My Favorite!!!! :mad:

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You said you were messing with the battery terminals earlier. I would check all the little wires between the battery and the power dist center. One may be losing a connection and you may have moved it causing a connection while messing with the battery.

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You said you were messing with the battery terminals earlier. I would check all the little wires between the battery and the power dist center. One may be losing a connection and you may have moved it causing a connection while messing with the battery.

 

Good idea Jim. Thanks.

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Idk how it does it but when my 3 solenoids went they would make it loose all power. When I would turn it to start it would click then nothing all power was lost.

 

Solenoids or relays? Only one solenoid AFAIK.

 

ps. I realize that they're sorta the same thing, since my Motocraft "solenoid" doesn't mechanically activate the starter.

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Do you have a volt meter? Measure the battery voltage on the battery posts when you are trying to start it. It should be more then 11 volts, if it drops below and doesn't crank over, the battery is either bad or does not have a full charge. If it measures good at the battery, measure at the the far end of the battery cables, to see if the cables might be bad. I have seen intermittent bad cables, they look fine but have a bad connection inside at the terminal ends. Hope this helps. I would say the ignition switch is good if you hear the starter relay clicking.

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Well, here's my report, such as it is:

 

I set out to test every theory posted here, and anything else I could.

 

Went out and turned the key; panel lights up.

 

But I wasn't quite ready to hear the *click* again, so I thought I'd try the old test of turning on the headlights and look for a voltage drop when the starter is engaged. Lights on, just fine. Engage starter, and it fires right up!

 

And . . . you guessed it . . . I haven't been able to get the symptoms to repeat in the last five days! IDK whether to be happy, or mad! :dunno:

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