97 Cherokee Sport -- Electrical/Charging Problem

tessa

New member
Evening all, and I hope you're having a happy holidays. Unfortunately, I'm not. This year's "holiday excitement" was my jeep dying on the way to the annual family get together :(

Problem started with an intermittent "check gauges" light on the dash -- voltmeter was showing nil when the light was on, but showing normal the rest of the time. Silly me chalked it up to a loose wire in the dash and thought it would be fine enough for the 40 mile drive. In hindsight, this was a horrible idea as apparently "check gauges" means "look at your gauges because there's a problem with your car" and not "hey, your gauge is malfunctioning." I really should know better, I've been working on cars since I was a little kid.

Halfway there, the radio cuts out and after another couple miles so do all the external lights (headlights, signal lights, brake lights, etc.). Car is still running at this point, so we hope to limp it the rest of the way. 2 blocks out, car dies completely -- engine cuts out, power steering is off, not even the interior lights or power locks work. So we get a poor man's tow the rest of the way, and, realizing the battery is dead, throw it on a charger.

Battery is fine, takes the charge, no error lights from the charger. Figure dead alternator. Hope fully charged battery will last a drive back to the house so we can get things fixed. Well...

Start the jeep, and it seems fine for the first minute or two. Back out of the driveway, onto the street and the engine cuts out again. This time, all lights are on, electrics all work, but headlights are dimming fast. Try to start it again, it turns over but won't sit in idle -- have to keep giving it gas or it dies again. Try to start it after one more die out, and she won't even crank anymore -- just hear the starter. But the electrics are still working at that point. Radio's fine, interior lights are fine, headlights are on, but dim.

Now we're driving a rental until we can get the troubleshooting done -- I refuse to go in to the shop without having at least a halfway decent idea of what needs to be done otherwise we get charged for things that didn't really need fixing :( -- and the jeep is sitting alone and lonely in front of my dad's house.

For the record: Starter is brand new (2 months old), so are spark plugs, battery, air filter, brake light switch, and a majority of gaskets on the oil system. I literally dropped 3k at the dealer to have it overhauled (didn't have the tools or the space to pull the transmission to fix the oil system). She does have a very minor pressure leak in the valve cover gasket that I'm aiming to fix soon (doesn't lose much in the way of oil, it's just reallll messy), and we go through an awful lot of coolant though we can never find an active leak (go figure?).

I'm pretty sure the current and most pressing problem is electrical (batteries don't just die for no reason), but I don't want to go spending the $200 on an alternator if the problem is something else.

On the list for testing are:
  • Battery (dying twice in one night doesn't bode well -- will probably just replace it no matter the condition)
    Cables/connectors
    Alternator
    Voltage regulator
    Fuses

Problem is, I'm not entirely sure how to test the voltage regulator as my poor jeep suffers from the idiocy that is having the voltage regulator be a part of the ECM. Can anyone offer some advice on that one? I read in a different forum that you could just disconnect it and try starting up to test it, but somehow that doesn't sound quite right (too easy, you know?).

I'm also not sure what other things I should test if everything on my list shows up as being okay. Crankshaft Position Sensor? Neutral Position Switch?

Any help would be greatly appreciated :)
 
Sorry, i tend to overlook those Tiny words sometimes. I think your headed the right direction on your list, just add ; Check wiring harness on the engine area for loose or pinched wires. make sure the grounds are secure to their respective fasteners.
 

No problem, and thanks. Ground connections and loose wires are already on the list as "check cables and connections" so I'm definitely going to be doing that (some of it this afternoon in fact).

Any direction on how to test the voltage regulator? It's part of the ECM, so I'm not entirely sure how to go about it. Is the bit I read elsewhere about disconnecting it then attempting to run the car an accurate test at all? Or is there something else I should do?
 
The only accurate way that i know of is using the DRB3. it's a Chrysler Scantool that can monitor the alternator output and trigger the voltage regulator. sorry i'm not much help outside of that. someone else here might know of a way.
 
Well, just from testing voltages, it would seem that the alternator is shot. Not surprising, really, as we've never replaced it before. Gonna throw a new one in and hope that fixes the problem.

Who'd have thought the alternator going out would cause the engine to die out with a fully charged battery o_O
 

i came on here to hopefully find out info or get help to this EXACT same problem with my 98 GC :) had a feeling it was the alternator as well and was gonna work on it today and get it tested before i do cause i don't wanna dump a bunch of money into something it didn't need . also :p sorry , not trying to hijack your thread , just letting you know you're not alone :D
 
i came on here to hopefully find out info or get help to this EXACT same problem with my 98 GC :) had a feeling it was the alternator as well and was gonna work on it today and get it tested before i do cause i don't wanna dump a bunch of money into something it didn't need . also :p sorry , not trying to hijack your thread , just letting you know you're not alone :D
Well, for me it was the alternator. Replaced it and no further issues.
 
Thank you for describing your problem. I have an almost identical issue. Is your new alternator still solving the problem?

Has anyone else solved this same problem?

I have the added symptoms:

While driving and noticing the check gauges light come on, I immediately pulled over and used my voltmeter to check things out. The voltage across the batter posts was only about 11 volts...ie, the alternator was not working since it should be about 14v. As per my mechanic, I proceeded to check the voltage from the battery negative post to each of the alternator connectors (ie, on the back of the alternator, the top big one and each of the two bottom small ones). The top and one small one both also showed about 11 volts and the other small one showed about 7v.

Then, just as I was testing (wondering if testing affected it), I heard the engine slow down a bit as the alternator suddenly started working (the alternator uses HP and slows the engine). The voltages jumped up to the proper 14 volts which apparently means the alternator is working and the battery is charging.

...BUT, when I looked at my guages, the volt meter was still showing zero and the guages light was still on. I just stopped and restarted the vehicle which always gets it working again.

What I'm not sure of, is if at first the voltmeter on the dash was far-far to the left - ie, negative. It may have been negative and then turned into zero once the alternator kicked in (described above) - but I'm not sure. Have to catch it again.
 

Thank you for describing your problem. I have an almost identical issue. Is your new alternator still solving the problem?

Has anyone else solved this same problem?

I have the added symptoms:

While driving and noticing the check gauges light come on, I immediately pulled over and used my voltmeter to check things out. The voltage across the batter posts was only about 11 volts...ie, the alternator was not working since it should be about 14v. As per my mechanic, I proceeded to check the voltage from the battery negative post to each of the alternator connectors (ie, on the back of the alternator, the top big one and each of the two bottom small ones). The top and one small one both also showed about 11 volts and the other small one showed about 7v.

Then, just as I was testing (wondering if testing affected it), I heard the engine slow down a bit as the alternator suddenly started working (the alternator uses HP and slows the engine). The voltages jumped up to the proper 14 volts which apparently means the alternator is working and the battery is charging.

...BUT, when I looked at my guages, the volt meter was still showing zero and the guages light was still on. I just stopped and restarted the vehicle which always gets it working again.

What I'm not sure of, is if at first the voltmeter on the dash was far-far to the left - ie, negative. It may have been negative and then turned into zero once the alternator kicked in (described above) - but I'm not sure. Have to catch it again.

Check the connections from the Alternator to the ASD relay and PCM for loose or corroded terminals.
 
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