dash idiot light ???'s
- Thread starter 88dually
- Start date
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Means there is a problem with the charging system. First thing I'd check are all the connections at the Alt and battery. Could be a bad battery too.
Some good advice here:
http://www.jeepkj.com/forum/f196/voltage-regulator-alternator-pcm-54616/
Some good advice here:
http://www.jeepkj.com/forum/f196/voltage-regulator-alternator-pcm-54616/
Last edited:
It's been a while since I checked mine but I think it connects to the block under the exhaust manifold on the drivers side. I've got a different project in the works right now so I can check mine in a bit but right now that's what I recall.
Actually it goes the other way. It is connected to the body near the battery. Rather flat spot above wheel well toward the driver with respect to the battery. I was following the wrong branch. It looks to be attached by a nut on a stud with another connector on top. So the (-) cable is rather short.
Whats really screwed up, its an intermitent problem. Some days light comes onn an goes off by itself. Sometimes it stays on til jeep is parked for the night. It usually takes z while driving before light comes on. WTH ???
That's what my Ranger did when the Alternator was going. When my KJ alternator went it just lit up and died very quickly. My 02 has a battery temp sensor on the tray Does your 03? If that goes flaky it'll throw the battery light too. I had to nurse mine home when the battery went years ago and the temporary battery didn't seat right in the tray so the light would stay on.
I'd say you are correct. But just a guess. Alternators aren't to bad to replace based on cost and difficulty so if yours is original it won't hurt.
The temp sensor is a little plunger like thing in the center of the tray if my memory is correct.
The temp sensor is a little plunger like thing in the center of the tray if my memory is correct.
The PCM -Power train control module may store a DTC code on the charging system.
I would want to have a scan done and see what hint may come from code if light is on.
Battery and connections are always first place to start. How old is the battery?
If you have removable electrolyte caps, get a hydrometer reading on each cell.
You could overnight put the battery on a charger and then see if light comes back on after driving as well...hint...
Load test it ...easy enough also to have a battery shop check it out for you with a digital tester and charging system analysis.
It is a good idea to replace the battery temp sensor in the tray when u replace the battery as well. Not an expensive part at all.
I would want to have a scan done and see what hint may come from code if light is on.
Battery and connections are always first place to start. How old is the battery?
If you have removable electrolyte caps, get a hydrometer reading on each cell.
You could overnight put the battery on a charger and then see if light comes back on after driving as well...hint...
Load test it ...easy enough also to have a battery shop check it out for you with a digital tester and charging system analysis.
It is a good idea to replace the battery temp sensor in the tray when u replace the battery as well. Not an expensive part at all.
Do you have a scanner to get codes? If not try key trick without starting from off to the On (no start) position. ..ON-OFF-ON-OFF-ON an leave it on ON..see what displays in the odometer...
Other wise I would have the ALT tested. When they get hot...stuff can go wrong.
Other wise I would have the ALT tested. When they get hot...stuff can go wrong.
uss2defiant
Full Access Member
local auto store should be able to test the alternator and battery.
yellocoyote
Administrator
Warning you that the entire battery harness is huge - lots of sections connecting to lots of different areas.
Looks similar to this:
Looks similar to this:
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uss2defiant
Full Access Member
my previous alternator issue was a bad +12v cable from the alternator to battery.
Billwill
Full Access Member
You need to pull codes out....as stated a faulty battery temp sensor also sets the battery light on. I had this problem....cannot remember what the codes were but they pointed straight to the battery temp sensor...not the alternator!
Make sure all the grounding cables are clean and tight such as the grounding cable grounding the engine to the chassis....you can get the codes out by rapidly turning the ignition ON/OFF 4 times without starting the engine...after the 4th time leave the ignition ON and the codes should display from the oldest to the newest.
If it is intermitant then check the cables on the alternator are on firmly...there is one thick cable going to the battery and a small plug with two wires....this is the regulation coming from the PCM as the alternator does not have its own regulator.
The thick wire going from the alternator to the battery actually has a built in "fusable link" but I am pretty sure that this link will either work or will be blown altogether...doubt it will be an intermittent problem.
You could try disconnect the battery and re-plug the connectors on the PCM in case there is a dirty connection and that is where the regulation comes from.
Make sure all the grounding cables are clean and tight such as the grounding cable grounding the engine to the chassis....you can get the codes out by rapidly turning the ignition ON/OFF 4 times without starting the engine...after the 4th time leave the ignition ON and the codes should display from the oldest to the newest.
If it is intermitant then check the cables on the alternator are on firmly...there is one thick cable going to the battery and a small plug with two wires....this is the regulation coming from the PCM as the alternator does not have its own regulator.
The thick wire going from the alternator to the battery actually has a built in "fusable link" but I am pretty sure that this link will either work or will be blown altogether...doubt it will be an intermittent problem.
You could try disconnect the battery and re-plug the connectors on the PCM in case there is a dirty connection and that is where the regulation comes from.
