Just bought a 96 XJ a month ago. Decided to start swapping my interior lights to LEDs. The previous owner ran a lot of different electrical wires everywhere (radio, speakers, maglite charger, amplifier, etc.) so I don't exactly know what is still hooked up and what isn't. Anyway my indicator bulbs for my transfer case and gearshift are not working. I put in the new LEDs and nothing so i thought maybe they weren't seating deep enough so i tried to use the glove box bulb, which worked in the glove box, and still nothing. Checked the fuse and it was good, which I assumed seeing as how the instrument panel lights are working. However I've tried to engage my 4wd and i can feel it shift into four but no lights (half time, full time, etc.) are lighting up in the box to the left of the gauges, nor are my climate control lights. Those could very easily be burnt out bulbs as I haven't checked yet. Not sure if maybe I checked the wrong fuse (number 17). Any help or wiring diagrams would be helpful.

 

Have you tried measuring to see if the socket gets voltage when it should? Have you tried to measure continuity to ground on the ground contact of the socket?

Check this post for info about manuals.

I could email you the wiring diagram page for a 94, but I don't know for sure it will apply to the 96. The 1996 model year was a bit of a bastard, a transitional year between the older electrical system and body style, and the newer one that came in with the 97 model year.

Even finding parts can be a bit wonky, as they used up old stocks. Some 96s will have newer parts and some will have older parts, and it's mix and match.

 

Hi '96 Jeep newbie.

circuit diagram on '96 is hard to obtain online, PM me

you need a test light and continuity tester (and maybe some piggyback wires) while owning a Cherokee XJ

it takes only a few mins to check both sides of every fuse with a test light

I had a scattering of blown/missing fuses in mine

the A5 HANDBOOK that (came with the car, if still present) for that year is the best place to check fuse locations..my 2 x '96 are different...even though they are both pre-update OBD2

 

I understand how to test for continuity on the ground but if it isn't getting any voltage would that be from a break in the wire somewhere? Not sure how you'd test for continuity on the hot wire. Sorry I'm not the best at understanding electrical but I'm learning

 

No problem, that's what this forum is for!

Step 1 is to pull the bulb and see if you have voltage at the socket when you expect it.

"But if I have voltage there, the bulb would light! I've checked the bulb and it's good. I'm not stupid, you know!"

No, I assumed you are not stupid and have already checked the bulb (not that any of us have ever spaced out the obvious stuff ), but there is a method in my madness. Hang in there with me. Use a meter to check for voltage, then use a test light to check for voltage. Yes, do both.

If you have voltage with the meter, but the test light won't light, you have a poor connection (likely corrosion) somewhere between the socket and the battery. The challenge is to find it, but now you know what you're looking for. (It might be the socket itself! Clean it!)

To understand the why of this better, read this. Also this.

If you have nothing either way, you have a complete break in the circuit, again, somewhere between the socket and the battery. And again, the challenge is to find it, but now you know what you're looking for.

If you can light the test light, the problem is in the ground side of the circuit. Again, either corrosion or an actual break.

Now, how do we go about that challenge of finding the actual problem? Running down electrical gremlins can be very difficult and time consuming. There are a lot of physical wires, and most of them are buried in bundles of other wires and are hard to get to. Where do you start?

Split.

"What?"

I said SPLIT! Whatsamatta? Ya got mud in your ears? SPLIT!

"Huh? Are you an old hippy, and you're telling me to leave?"

No, no. Old in some folks view, yes, but I ain't no dirty hippy!

You need to do what we call, "circuit splitting". It's rather like using bracketing when calling in artillery fire. (I assume you know how to do that, right? )

The idea is to use a systematic approach to find the problem (get rounds on target) with the fewest attempts.

First step is to get a diagram of the system. You need to understand what physical pieces make up your circuit. Then, you need to visualize how it works. Functionally, think of any circuit like a straight vertical line. At the top is the battery. At the bottom is ground. Somewhere along that line is your device. It could be a blower motor, it could be a door lock actuator, it could be a light bulb.

Usually, the load (your device, the light bulb) is right above ground.* Somewhere above the load is a switch of some kind, and above that is a fuse, then the battery. We will probably have various connectors scattered here and there along the line, too, and maybe a relay thrown in just for fun. Like this:

Battery
|
Fuse
|
Switch
|
Load
|
Ground


And throw in a few random connectors here and there. You might have a a half dozen (sometimes more) above your load. Each one of those is a potential problem child. Wires themselves sometimes break, too, but if they are in a bundle with a bunch of others, not usually. Wires that flex, of course, are a different matter. The door window and lock wires, or the third brake light and rear washer are good examples of wires that often break.

Anyway, once you have the circuit laid out in your mind, pick a place near the middle, preferably a connector, where you can find it physically and test it. Let's call this Test Point 1. (In the very simple circuit above, I'd probably pick the hot connection to the switch. That will test everything from the fuse to the switch. In a real circuit, there would probably be a few connectors above that point, and maybe a relay. Testing at the switch input just tested them all.)


Test that spot. Does it behave correctly? If yes, the problem is below you. No need to look at anything above that point. If no, the problem is above. No need to test below (yet**).

If above, find a place halfway between where you are, and the battery. That's Test Point 2. Test it. If it works correctly, the problem is between test point 1 and test point 2. If not, the problem is above Test Point 2.

Find a place halfway between Test Point 2 and the battery.

Get the idea? Each test tells you to go below or above. Split that part of the circuit, and test again.

This method gets you rounds on target with the fewest steps.

If you just start guessing and asking people "what did you replace/fix when you had this problem", you'll cause yourself a lot of frustration, wasted time, and probably wasted money. I have seen people give up and sell the car at a big loss, when they didn't need to.


Now, if all of that was a bit much to digest in one sitting, feel free to throw some questions at me. If you think you've got it, get busy testing!

Holler if you get stuck.


*(Sometimes, we have a switch between load and ground, but not often.)

**(There could be problems above AND below a given test point! But stick with the system!)

 

fabulous long answer, only thing I can add,

make a test probe with a small safety pin, use it to stab wire, (or back-probe connectors).. seal with superglue, saves a lot of time

or you can buy fancy hands needle probes from the electronic shop

 

Looked and looked last few days and cant seem to find any wiring diagrams online for the 96. 84-93 and 97 on only. Been contemplating buying a Haynes manual. Do those have the circuit diagrams in them? And is it worth it?

 

Did you PM member 'awg'? It sounds like he might be able to help you with wiring diagrams.

Don't waste your money on a Haynes manual. Get yourself a Factory Service Manual. You can try Pacific Coast Manuals online.

You might want to check the connector at the transfer case and see if there are any obvious signs of a problem (dirty connector, bad wires). If you get no power to the light when it's on you could be getting no signal from the transfer case letting you know 4wd is engaged. Engaging 4wd is completely mechanical, lighting up the light is electric.

 

I have a photocopy of the (most) of the Electrical manual for a '96 converted to a number of .Pdf

its probably similar to the '97

I can PM relevant sections to ppl, if u ask nice

to the OP, circuit 87, illumination feeds the 4wd lamp, not much help
note the wire color
it can be traced back thru various connectors

but it is usually MUCH easier to just pick up 12V somewhere else

you indicate the ground side is ok, that means everything is working but no 12V..are you sure continuity to ground only takes place upon 4wd switch actuation?

probably a dodgy plug, connector or wire

 

Okay so I ended up purchasing the FSM from Pacific Coast. Trying to figure out how to read this diagram has got me all kinds of confused lol. I see PRNDL Illumination and 4WD illumination on several diagrams (junction block lhd, junction block rhd, ground distribution, etc.) Any explanation in layman's terms would be greatly appreciated.

 

unfortunately, the factory circuit diagrams are confusing imo

in laymans terms, you can check the wire color from the code, and trace that back thru connectors

regretably it isnt usually so simple, without dismantling the Jeeps dashboard


what I do is this;

* establish if 12V is where it should be, working back, light, socket, wire, connector..up to harness..IF everything else is working that means it is confined to one "thing"..ie no 12V on that wire,,,easy fix, patch 12v in! (preferably fused)

* does continuity to ground take place thru a switch, does it work as it should, adjustment, wiring etc etc

just be systematic ie
does the light come on in situ, if u give it 12V and -ve ?
does it light if you give it 12V and earth the switch wire etc etc


desirable to have working my 242 is hard to get to change usually, and the light is helpful