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electrical issues?

S

swstevenson24

NAXJA Forum User
Location
Florence, Alabama
so a little back story.. I have a 1996 XJ 4.0 and it ran like a top except reverse and 1st gear would grind. So I decided to pull the transmission thinking I would resolve the problem quickly. That was 2 years ago... I FINALLY got a good used transmission in it from a 97, and drove it home from my F-I-L shop with the GEN light on. So I bought a new alternator and a new battery. Slapped the new battery in it, and it would crank just like new. So I moved it around my property a couple of times the next day, and it quit starting. The alternator came later that day, and by that evening I had it in too and thought my problems would be solved. I took the battery out and charged it while i replaced the alternator, and when i finally went to crank it up I got crickets. All electronics come on, and everything looks usual aside from it not starting. The only thing I can see different is that now the buzz happens immediately when the door opens rather than when the door opens with the key in ignition. I am out of ideas, and cant find anything online related to my problem. any help or ideas is greatly greatly appreciated!!
 
Bad ignition switch? Have you tried jumping the solenoid and seeing if she cranks?

If an automatic, possibly the NSS needs refurbished. Does it start with the shifter in (N).
 
I would be checking grounds. The one by the dipstick would be the first one I would look at.

This thread has my own experience with that ground on my '96: https://www.naxja.org/forum/showthread.php?t=1148570

ETA: In what condition are your battery cables? If your cables are original, running the common, cheap auto parts store replacement terminals, then that is probably the first place to start. And at this age, pay attention to the connections at the other ends too.
 
Last edited:
So after some deep diving and tinkering, I jumped the starter, and found that the NSS on the replacement trans needed replacing so I put the one from my original trans back on and that solved the no crank no start issue. NOW I have realized that the alternator didnt necessarily have to be replaced, because what I discovered is that something (no idea what as of now) is pulling such a load off the battery that the alternator cant keep up while driving. I imagine that is why the buzzer is going off without the key in ignition when the door opens (as if I left my lights on). Still don't know where to start looking for that, but I will check out the grounds. As for the battery terminals they are original as far as I know and definitely needed attention but after a good cleaning they seem to look okay... So now what?
 
So since my last response I have run a parasitic draw test. Here is what I found. The annoying buzzer is supposed to only sound when the key is in the ignition and door open. Mine is constant as if I left headlights on or something. I thought that HAD to do with my parasitic draw so I started pulling fuses. I pulled the #15 fuse and that seemed to do the trick as far as making the buzzer go back to normal. BUT the voltage tester still lights up when I do the draw test, so I dont know what to think... any help?
 
The voltage tester lighting up does not give you enough information. Can you use a multimeter to check the amps drawn?

If you have a computer you have a draw. If you have a stereo that keeps a clock you have a draw. The amount of draw is what you need to be concerned about at this point.

The link between the hyperactive buzzer and the excessive draw may be a valid one, and you may be on the right track with that. The remaining draw may be nothing more than what is required for the rest of the systems to function. But to really know you need to measure the draw.
 
So used a multimeter on the XJ. It was reading 12.03 with the fuse installed, and 12.08 with the fuse pulled. When I cranked the jeep I noticed a couple things. Only one fan blade is spinning and my belt seemed to be moving fairly slow, but with the jeep off it seems to have good tension on it so IDK. The other thing I noticed is the brand new alternator is only putting out 11.56 volts at idle while the battery is putting off 11.58 at idle. so what now?
 
The second fan that is not running should be your electric fan. If you switch on the AC it should kick on. Otherwise it kicks on when the temperature gets up to a certain level. (At least that is my understanding--I haven't had to fret over that function).

With regard to your readings of 12.03 vs 12.08, are those amps or volts? It doesn't make any sense that you should be drawing more amps when you remove a fuse, but I can conceive of how volts would go up if you removed a fuse on a problem circuit. Some clarity is needed on this one.

I have nothing to offer on belt speed. Way too subjective.

How are you measuring battery vs alternator at idle? At what points in the system are you taking these readings? Either way, those numbers are too low. My Cummins puts out numbers like that until the grid heaters kick off. Either you have some serious draw in the system (and whatever that draw is it should be generating measureable heat) or you have a charging problem.

Do not assume that a replacement alternator actually works.
 
So the #15 fuse was definitely the parasitic circuit. I woke up this morning and still had 12.06 on the multimeter. I dont think I missed anything reconnecting anything to the alternator, but I suppose I could recheck that. The unit is a brand new ACDELCO off rockauto. not a reman.
 
That is a good start.

Regardless of its source, at this point and given the situation, it would be worth your while to get the alternator tested and/or swap in another known good one. New parts are not trustworthy. We all wish we could rely on them, but many of us have experience to the contrary.

Actually, if you still have the old alternator on hand (new AC Delco? No core required?) I would have that one tested first. If that one tests good I would swap it back in and see how the situation changes (if at all) and get the AC Delco unit tested. It is conceivable that you have a problem with the voltage regulator. In case you are not aware the voltage regulator is actually part of the ECU. If the voltage regulator has gone bad you can either replace the ECU or convert the system over to use an external voltage regulator.

Get the alternator tested and confirmed first.
 
I'll do that! I didnt have to exchange the alternator for a core, so I still have the old one. And I still got a GEN light pop up before I swapped it so I would almost bet that its the voltage regulator. Isnt that the box that is bolted to the bottom of the alternator. I'll still have both alternators tested though
 
If your voltage regulator has gone bad (and it is part of the ECU, not part of the alternator) you can either replace the ECU or you can convert your system over to run an external voltage regulator. Here is an example of one kit: https://store.alternatorparts.com/hd-external-voltage-regulator-conversion-field-replacement-kit.aspx?gclid=CjwKCAiA1JGRBhBSEiwAxXblwXk1IH_MraRP8RFyJCF7MsTNSR14X9nzPNDUbXBatpXOCPtBoP-lRBoCmLMQAvD_BwE

Do a search for "Jeep XJ external voltage regulator" and you will find options for kits as well as video tutorials.

ETA: Research that circuit #15 for which you have pulled the fuse and make sure it isn't related to this problem. If fixing whatever is wrong with that circuit will also fix the voltage regulator side of this equation then that is where you should direct your energy.
 
Tighten the serpentine belt.

When engine is running check voltage at large wire at back of alt, should be around 14 volts, that is what charges the battery.
 
swstevenson24 said:
So since my last response I have run a parasitic draw test. Here is what I found. The annoying buzzer is supposed to only sound when the key is in the ignition and door open. Mine is constant as if I left headlights on or something. I thought that HAD to do with my parasitic draw so I started pulling fuses. I pulled the #15 fuse and that seemed to do the trick as far as making the buzzer go back to normal. BUT the voltage tester still lights up when I do the draw test, so I dont know what to think... any help?
Click to expand...

Looking at 1996 drawings:
Fuse 15 in the underhood PDC = F15 30a Radiator Fan Relay.
Fuse 15 in the underdash fusebox = 15A I.P Lamps, Clock, Radio/Clock & Memory, Headlamp Switch, Park Lamp

It doesn't take much current to light up a test light, even the normal ignition off draw will light it up some. Best bet you be measuring with a meter - note that it may spike at first as things get power, for example the radio will try to eject any CDs.

If your voltage isn't coming up beyond 12-volts when running, I think you've got a charging problem. See if you've got voltage across the field coil on the back by measuring at the connector while plugged in. It should have +12volts to it, and the computer controls the ground side of the coil. If you see 12volts on both sides of the connector, then the computer isn't doing its job. If you have both sides grounded, then it's not getting power. Either of which could be a wiring issue.
 
So what I found was that #15 circuit is what controls my dash dimmer, but I haven’t tracked down what all else it controls. Everything I have seen online say it’s the headlight switch, dash dimmer, radio/clock memory, but the only thing that doesn’t work since pulling the fuse is the dash dimmer.
 
So I ran the multimeter across the alternator, and both sides of the field coil while the Jeep was running. Alternator was reading 11.56. Right side of the coil read 11.48, and left side of the coil read 11.39.. does that mean I need an external voltage regulator to bypass the PCM internal VR?
 
swstevenson24 said:
So I ran the multimeter across the alternator, and both sides of the field coil while the Jeep was running. Alternator was reading 11.56. Right side of the coil read 11.48, and left side of the coil read 11.39.. does that mean I need an external voltage regulator to bypass the PCM internal VR?
Click to expand...

Also my belt is tight. No squeak or anything
 
Have you gotten the alternator tested yet?
 
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