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Blowing Fuse #17(Instrument Cluster)

Alexia

NAXJA Forum User
Location
Huntsville, AL
1996 Jeep Cherokee Classic 4.0, AW4, 2WD

I have a crazy wiring issue I could use assistance diagnosing. I know it is a short some where and I really want to avoid ripping out the dash to fully inspect the wiring harness.

Fuse #17 for the instrument cluster gauges blows the moment the key gets into the run position.

I have disconnected:
  • Instrument Cluster
  • Headlight Switch
  • Multi-function switch
  • Clock Spring
  • Intermittent wiper module
  • All the relays in the under dash relay center.(The flasher and door lock relays should not affect it, but whatever I'm desperate.)
  • Radio(Well, it was never there.)

12 volts is still present across the fuse position with all those disconnect and the key in the run position indicating a short some where.

Am I doomed to ripped the dash out to inspect the harness completely?
Is there something else that gets power from this fuse I am unaware of?
What color are the wires coming off that fuse?
 
Mine was doing that same thing....and it turned out to be the turn signal processor on my trailer light harness. Of course, I figured that out after replacing all of the bulbs in my gauge cluster and disconnecting everything like you did. Hope this helps.
 
Mine was doing that same thing....and it turned out to be the turn signal processor on my trailer light harness. Of course, I figured that out after replacing all of the bulbs in my gauge cluster and disconnecting everything like you did. Hope this helps.

This has to do with the gauges though, not the illumination.
 
How long ago did this problem start?
Was it after doing any work on the Jeep?

If you have access to a Factory Service Manual for your year XJ; you should consider borrowing one to assist in troubleshooting the problem.

You might consider purchasing one on EBay; it is a worth while investment.
The FSM was the first thing I purchased for the Jeep after buying the XJ new in 1997.
 
How long ago did this problem start?
Was it after doing any work on the Jeep?

If you have access to a Factory Service Manual for your year XJ; you should consider borrowing one to assist in troubleshooting the problem.

You might consider purchasing one on EBay; it is a worth while investment.
The FSM was the first thing I purchased for the Jeep after buying the XJ new in 1997.

The problem existed before I bought the Jeep about two months ago for restoration.

I know the problem exists solely within the under dash wiring harness.(I disconnected the bulkhead connector a few days ago.)

I do have a FSM and it has helped me understand how the wiring runs. Unfortunately it just looks like the wiring short is happening in an area that will require removing the harness and possibly unwrapping the wire clusters.

The power comes in through the red and purple wires on the ignition switch then flows out the blue wire to several spots, namely the input side of fuse #17. However, the output side of the fuse is grounded somewhere. The back side of the fuse block looks fine. The wires at the instrument cluster look fine. The unknown is where the harness goes up into the dash and possibly to the headliner. I have a suspicion the issue may be coming from some where up there or something that happened when wiring was run up that way for roof rack lights.(All the wiring for that has been removed though.) It looks like the wiring for the roof rack was brute forced into place.
 
Here is what I would do. Grab a test light and hook it across the battery. Note how brightly it shines. Now hook the test light up to the fuse box in place of the fuse, across the terminals. When the short that blows the fuse is present, the light will glow as brightly as when hooked to the battery. Now wiggle the harnesses to all the listed components on that circuit and watch for the light to flicker.

This works great on intermittent problems, but if a harness has melted and it's a full-time short, you may have to put hands on every inch of wire.
 
I may be off base here, but isn't 17 the door chime and headlight delay module? My 96 is kind of an oddball, half 95 and half 96, so it may be different than yours. I was having door chime issues and fuse 17 was what I pulled, when troubleshooting.
 
with 8mud on this one!

96 is NOT the same as 95 OR 97 so watch out on the wiring.
Exact year FSM really needed.

96: " fuse 17 -7.5 amp violet-- instrument cluster gauges, headlamp delay module, chime module, overhead console."

Try disconnecting the headlight delay module and chime module and retest.
Just a thought- next might find the wire in rt. kick panel going up to overhead console and cut it, to test again, to see if problem is up there, reconnect later.

Good Luck,
Orange
 
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Here is what I would do. Grab a test light and hook it across the battery. Note how brightly it shines. Now hook the test light up to the fuse box in place of the fuse, across the terminals. When the short that blows the fuse is present, the light will glow as brightly as when hooked to the battery. Now wiggle the harnesses to all the listed components on that circuit and watch for the light to flicker.

This works great on intermittent problems, but if a harness has melted and it's a full-time short, you may have to put hands on every inch of wire.

Yeah, it is a full time short. With every device disconnected, bulkhead connector disconnected, and a bunch of grounds disconnect it is still shorted to ground.

I um... accidentally finished breaking the dash in half that a previous owner started. Went to remove the right face plate after removing the screws and found it had been glued to the dash which ripped apart when I gave it a tug.

Hey, I have easier access to the wiring now! I will let you guys know once I figure it out. I did see that the power wires to the the overhead console, gauges, chime, and delay module all are getting grounded. Every portion of the wire tests to ground so it is just in there some where. I even checked the obvious wear and tear around at the floor wells.
 
The good news is that the wiring was not shorting itself to the body. It is shorting to a ground wire inside the harness somewhere. Still have to figure out where.
 
Using a good wiring diagram, not like one in Chilton or Haynes.. break the circuit down into individual sections and keep retesting.

You can use a circuit breaker in place of fuses to save on fuse cost while investigating, but don't leave it plugged in while shorted and assume it's going to go completely open. It will heat wires up if the short is still present so keep that in mind.
 
Ahahahahahaha...

Just finished installing the replacement dash and wiring harness.

Fzzz POP!

On a whim I disconnected the brake light switch. No more grounding, fuse is fine. The freaking BRAKE LIGHT SWITCH was the issue the whole time!

:flame:
 
Ahahahahahaha...

Just finished installing the replacement dash and wiring harness.

Fzzz POP!

On a whim I disconnected the brake light switch. No more grounding, fuse is fine. The freaking BRAKE LIGHT SWITCH was the issue the whole time!

:flame:

Well, I guess that was wrong or I'm about ready to trash this thing.

1.) Replacement dash/fuse box wiring harness works fine, does not test to ground on fuse #17.
2.) Does test to ground to ground after complete reinstallation.
3.) Disconnected the brake light switch, fixed! Wow, all that hassle over a switch.
4.) Replacement brake light switch... Testing to ground again, WTF?
5.) Disconnect brand new brake light switch, still testing to ground! HOLY WTF!
6.) Completely isolated replacement dash harness/fuse box. Still testing to ground. Now this harness is acting like the old one.(However, the old harness is fine now that it is out of the vehicle.)

Even with a FSM this problem is freaking insane. I am contemplating running a separate wiring harness to the gauges just to fix and get around this issue.

There is something so screw ball that it can mess up this one wiring portion and not be obvious where the issue is located.
 
I noticed disconnecting the gauge cluster stopped the grounding, now.(Weird, I believe there were two different grounding issues.) I removed the oil pressure gauge and no more grounding! The sensor itself is fine, I tested it with a known working unit. Just the gauge itself is busted. Any one know of a replacement gauge or will I be finding a replacement cluster?
 
I noticed disconnecting the gauge cluster stopped the grounding, now.(Weird, I believe there were two different grounding issues.) I removed the oil pressure gauge and no more grounding! The sensor itself is fine, I tested it with a known working unit. Just the gauge itself is busted. Any one know of a replacement gauge or will I be finding a replacement cluster?

Just put the gauge cluster back in minus the oil gauge, just like I did an hour ago, and it is grounding again. This is the worst issue I have ever worked with!

Disconnecting the grey connector on the body harness and the brake switch prevents the grounding issue. This disables all the power features. Might be the wires in the driver's door grounding out from years of moving.
 
What it comes down to has something to do with the device on the ignition interlock.

Wire path:
1.) White with black tracer comes from output side of Fuse #17, goes to gauges, headlight delay module, overhead console, instrument illumination, and the device on the ignition interlock.(Note: I'm not sure what the thing is for. All I know that it does is make my life worse and it is a little canister the sits in between the cable.)

2.) The through the ignition interlock device it goes out to the white wire with pink tracer, which goes to the brake light switch.

3.) The brake light switch is always grounded when not pressed. So the white with pink tracer wire goes in and immediately goes out to the black grounding wire that hooks to the dash.

Apply power to the ignition interlock does nothing. However, the shifter still works as long as the key is turned.

Edit: Just figured out what this thing does. It prevents the key from being turned while in gear or going into gear without pressing the brake. The thing is totally broken, but I can still shift fine. Whatever! All because of this stupid little safety device.
 
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Just curious - did this fix your problem? We just bought a 1996 jeep about a month ago. Noticed that both tail lights and brake lights went out - replaced bulbs and fuses. Now cruise control, power windows & power door locks don't work - fuses keep blowing. Trying to decide where to start...
 
I have a 98 Xj and mine just started doing something similar, my dome lights, CD player, door chime, and my brake lights are on constant with the lights. I have no clue where to start other than try a brake light switch in the morning. Any insight would be great thanks
 
I am having this same problem. All lights in my cluster work. Yet the #17 fuse blows automatically when the key is in the on position. Cannot find any break in any wires in the harness. Have absolutly no idea.! Please help.!!!
 
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