Starter, alternator, or both?

damselNOTindistress

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Ridgway, CO
Yesterday, I got up, started the Jeep in 7* weather, drove to work, drove back to my town, and then ... dead in the water at the post office.

I got nothing. No lights on the dash, just a click could be heard at the starter solenoid. I checked the battery voltage (it was only at 12.6 V which seemed pretty low since I just ran down the high way home for 15 minutes). I took the battery connections off, cleaned them, still nothing. My friend tried to give me a jump, which didn't work, and after that the battery voltage was at 12.3 V.

Since I live at 7000' in Colorado and it's January, I threw up my hands at this point and my friend towed me the three blocks back to my house. I put the battery on a trickle charger overnight (still in the Jeep) and the voltage didn't budge. I had a different friend (I live in a small town and I can't buy shit here but at least the community is helpful) pick me up a new battery when he was in our nearest big city for errands and stuff. Nothing. Still just a click. (Now I have the old battery on the trickle charger out of the car and it seems to be charging.) I checked the hot wire to the alternator and there's no drop from the battery voltage. I didn't have a friend available to crank the engine and see if the voltage dropped.

This leads me to believe I need a new starter (being delivered tomorrow). BUT, the battery was low after driving down the highway. Do I have a bad alternator AND a bad starter? (I also ordered an alternator.) I'm just trying to figure out my order of operations tomorrow when I get home since I only have an hour or so of daylight.

Am I missing something? Neutral safety switch? Something in the ignition itself?
 
You wont be able to test the alternator until you can get the Jeep started to see what the voltage is at the charging stud of the alternator. The charging of the battery is controlled by the ECU by reading the system voltage.
Ensure the negative battery cable connection at the stud on the block next to the oil filter is clean and tight, the ground cable clamp is clean and tight to the battery terminal, the positive cable clamp is clean and tight to the battery and the connection to the starter solenoid is clean and tight.
When trying to start the engine; give the starter a few taps with a hammer. I have had good results getting starters to crank over on the trail. You may need to inspect the brushes and slip rings for worn components or dirty parts.
 
I checked the battery voltage (it was only at 12.6 V which seemed pretty low since I just ran down the high way home for 15 minutes).
This is normal voltage for a battery when the engine is off.
However, whether it can maintain that voltage under load (when starting) is another story.

When you say it's dead and won't start, do the headlights still come on bright?
 
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When you say it's dead and won't start, do the headlights still come on bright?
Hadn't tried this. Yes, the headlights come on nice and bright. And then, fun twist, I tried to crank it and they went out.

I came in out of the cold, thought on it for awhile, went back out and tried again. They wouldn't turn on until I turned the key to "on" (not to start) and again went out when trying to crank.

Ensure the negative battery cable connection at the stud on the block next to the oil filter is clean and tight, the ground cable clamp is clean and tight to the battery terminal
Do you mean the negative battery cable connection is clean and tight to the battery terminal and the ground cable clamp is clean and tight to the stud on the block? A ground issue is kinda starting to make sense.
 
Do you mean the negative battery cable connection is clean and tight to the battery terminal and the ground cable clamp is clean and tight to the stud on the block? A ground issue is kind of starting to make sense.
Yes.... Grounds can disrupt power transfer too....
 
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As @CharlesHS said, old trick, try lightly tapping the starter solenoid with a small hammer. Just be careful not to hit near the electrical connections. Then try to start it. Sometimes the solenoid sticks and this helps knock it loose. If this works, then it's a good idea to replace the starter.
 
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It could be the ignition switch actuator pin. I could tell a big difference after I changed mine out. Before it didn't feel like the key was turning much of anything but after replacing I could feel the resistance.
 
Before it didn't feel like the key was turning much of anything but after replacing I could feel the resistance
As I noted to LONGJP2, something happens when I turn it to start though. It shuts down everything. It seems like turning to “start” definitely does something. Is that consistent with ignition switch actuator pin?
 
Does it have a manual transmission? Maybe you can push start it to rule out the battery. Might need to remove the fuse that overrides the clutch safety switch.
 
As I noted to LONGJP2, something happens when I turn it to start though. It shuts down everything. It seems like turning to “start” definitely does something. Is that consistent with ignition switch actuator pin?
Not sure I think I remember the radio coming on and when I tried to start the radio would go off, you can always remove it and inspect. It was pretty obvious that mine was broken when I pulled it out. Below you can see how there is a small chunk broken off. I think that is where it is commonly broken if that's your problem. Link for this video below.

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If that's your problem you can start your jeep but I don't remember exactly how my brother in law did it. I think he just connected a wire from the battery to the starter with the key in the on position. just be careful if you try this method. Once it's on you can disconnect the wires
 
Does it have a manual transmission? Maybe you can push start it to rule out the battery. Might need to remove the fuse that overrides the clutch safety switch.
It is a manual but it's parked on damn flat ground. :-/ I put a new battery in so I'm pretty sure it's not the battery.
 
It is a manual but it's parked on damn flat ground. :-/ I put a new battery in so I'm pretty sure it's not the battery.

This once happened to me on a cold night. I ended up calling Triple A and we both were like what the F. Long story short, the fuse box by the battery had a loose connection. It needed to be tightened. I would check all of those grounds as well for a loose connection. Any aftermarket equipment, like winch or amplifier?

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With the key in the run position, and THE JEEP IN NEUTRAL, try to jump the starter. If it cranks, it eliminates the starter, and we can go from there.
 
Lights dimming while trying to start engine means another load (the starter) is being put on the battery.
Either the starter is bad and won't turn, or something is locked up and it can't turn.
 
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It isn't your battery. A 12V battery is actually 6 x 2.1V cells. 12.6V is completely charged. Which also rules out your alternator, since driving in that cold, presumably with the blower on, would have dropped the voltage below 12.6V by the time you stopped.

Which leaves clutch interlock, ignition switch, and starter/solenoid. The click indicates the solenoid is working, so we've now ruled out the clutch interlock, ignition, and solenoid as well. So now we have starter and wiring to the starter. Make sure everything is well attached all the way to the battery.

After that I would replace the starter. I probably missed something in there, but that is how I read the situation...

Doug
 
Hadn't tried this. Yes, the headlights come on nice and bright. And then, fun twist, I tried to crank it and they went out.
That the headlights go out when the ignition switch is in the Start position indicates a bad battery, a bad battery connection, or a bad battery cable.

If the headlights stayed on when the ignition switch was in the Start position that'd indicate a good battery and good battery connections. Possible sources of that problem being a bad starter motor or a bad ignition switch pin.
 
Being you have tried a new battery that eliminates that. You may have a bad cable connection, including your ground cable. You need to have someone try to start it while you are at the battery with a meter to check voltage at the battery and cables. Also check to frame ground. This will eliminate things and you can move forward without guessing.
 
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I went on a connection cleaning binge after work. (I had to be online for a Town Council meeting at 5:30 so I only had an hour.) I seriously cleaned the positive and negative cables, removed some wiring from old KC lights that have been long gone, cleaned the connection at the relay box, and cleaned the ground on the block just to the rear of the oil filter.

I have no idea which one of those did it (I figured all were things that could/should be done anyway) but it started right up. I'd already cleaned the positive and negative cables so I'm guessing it was that ground or the connection at the relay box (both of which would give me those weird and varied electrical responses if the connections were marginal).

Thank you all for your help. It's always helpful to have someone(s) to process your thinking with!