Dome Light Fuse--keeps blowing

[coolwind57]

I have an on-going issue for a Month or two.  I thought it was my clock shorting out or something, but now that I have a new one I've found that it wasn't the culprit.  Here's the deal:

 

I can't put a fuse in the DOME slot without instantaneous blowing of said fuse. 

 

From my understanding, that dome circuit stays HOT at all times, powering RADIO memory, CIGARETTE Lighter (I think), GLOVE BOX light, and DOME LIGHTS (when door is opened and the door switches close allow grounding to complete the circuit).  I've checked connections and then even unplugged my Euramtec DOME lights, pulled fuse from RADIO, disconnected radio harness, disconnected cigarette lighter connections, and finally disconnected clock.  Still, I blow any fuse as I begin to plug one in the fusebox.

 

Unfortunately, I have no a diagram nor a multimeter here today and I've got about an hour or two before I have to give up for the day.  Am I missing anything?

 

Would the headlight pull switch have anything to do with this issue maybe?

 

Unless you guys can point me to an area I hadn't thought of, my next step is to go pick up more fuses, buy a torx socket that fits the seatbelt shoulder harness bolt and take off the pillar covers to inspect the dome light wiring behind there for ground outs.

 

Anything else come to mind, fellas? 

 

 

[jdog]

do you have a bed light?

[coolwind57]

29 minutes ago, jdog said:

do you have a bed light?

No.  No cargo light.  I see the wiring provided by Jeep for it, though.  Still neatly wrapped in the wiring harness for the dome lights.

 

[eaglescout526]

Did you remove the door switches and check them out? Maybe one of the power wires is barely hanging on and is touching the body of the switch and shorting out. 

[coolwind57]

32 minutes ago, eaglescout526 said:

Did you remove the door switches and check them out? Maybe one of the power wires is barely hanging on and is touching the body of the switch and shorting out. 

I did pull the door switches.  Inspected and cleaned them.  I don't think there are power wires in this system. 

 

It is my understanding that they provide only ground to the circuit when the doors are opened.  It's kind of a spring loaded plunger that connects the body of the truck to the wire terminals--but only once the plunger is forced out by the opening of the doors.  There is one spade terminal on the passenger side, and two spade terminals on the driver's side.  Unless I'm way off, then this is the way it works.  And it made sense when you look at the action of the switches.  But I may be wrong. 

[jdog]

have you tried unhooking the glove box light?

I would put a ohm meter on ohms with the fuse removed put one lead into a pink wire that goes to the lights and the other to ground, start unplugging and moving the harness and wathcing the meter, when you have infinite resistance you have found the problem. book shows that wire runs the glove box lamp, cargo lamp switch, dome lights and the floor lamps.  door switches are just grounds

[coolwind57]

1 hour ago, jdog said:

have you tried unhooking the glove box light?

I would put a ohm meter on ohms with the fuse removed put one lead into a pink wire that goes to the lights and the other to ground, start unplugging and moving the harness and wathcing the meter, when you have infinite resistance you have found the problem. book shows that wire runs the glove box lamp, cargo lamp switch, dome lights and the floor lamps.  door switches are just grounds

I had unplugged the glove box light at the switch harness (inside the glove box).  That might had been after I popped my last fuse.

 

I'm going in to my work tonight and I'll pick up my multimeter.  this sucks.

[JustEmptyEveryPocket]

THIS ITEM instead of a box of fuses for testing purposes? Otherwise I have no good ideas for you.

[coolwind57]

1 hour ago, JustEmptyEveryPocket said:

THIS ITEM instead of a box of fuses for testing purposes? Otherwise I have no good ideas for you.

That is pretty sweet.  Didn't know they had such a thing.

[JustEmptyEveryPocket]

I watched a video by SouthMain Auto where he used an automatic resetting fuse. Couldn't find that exact thing back though. Anyways, good luck.

 

Last resort is to put a paperclip in place of the fuse and follow the smoke . . .

[jdog]

26 minutes ago, JustEmptyEveryPocket said:

I watched a video by SouthMain Auto where he used an automatic resetting fuse. Couldn't find that exact thing back though. Anyways, good luck.

 

Last resort is to put a paperclip in place of the fuse and follow the smoke . . .

auto parts stores sell them, they are auto resetting circuit breakers

[coolwind57]

10 hours ago, JustEmptyEveryPocket said:

Last resort is to put a paperclip in place of the fuse and follow the smoke . . .

That's GENIUS!  Hadn't thought of that!  Haha.  

 

Maybe I'd better exhaust all other options first.  But great tip, man!  haha

[coolwind57]

Anyone got a wiring diagram for this dome circuit?  I can't seem to find one anywhere on the internet.

[coolwind57]

Well I just found an 88' Troubleshooting manual on here afterall, so disregard with wiring diagram request above.  Interior lamps schematic is on page 63.  

 

Here's the manual if anyone else needs it:  

https://comancheclub.com/applications/core/interface/file/attachment.php?id=14915

[88towmanche]

When I installed the Euro lights in mine, found that BOTH lights have to be hooked up or the fuse blows every time....

 

Install went:

 

Pull OEM lights, clean everything up, install driver side replacement Euroteck light and bam - fuse blows.

 

$#!&

 

Try again with new fuse double check everything....bam, fuse blows.

 

Damn

 

Ok, forget driver side let's at least get passenger side in - install passenger side Euro light and bam - fuse blows

 

Crap

 

Try again with new fuse, double check everything....bam, fuse blows.

 

WTF

 

Ok, install both lights complete and THEN plug fuse in - Golden!  never had a problem since.

 

 

 

 

[coolwind57]

Well, I found my problem.  There's a wiring bundle connector just behind the kick panel, driver's side.  That sucker looks like it took a missile hit.  Wiring is all melted together something awful. 

 

I'm hoping that there was just some bad connection within the connector that caused the overheating.  Or may some rubbing that caused it.  I've started my repair, which consists of deleting the connector and soldering in ten each, 6" wires.  I don't have enough length after cutting out the connector.   Melted wires were entirely on the rearward end of the connector, not the front end.  Connector itself took only minor damage.  It was the inch or so after the connector where all the wire melting took place.  

 

Without knowing the exact cause of the overheating, I suppose I'm going to finish my soldering and checking for heat once I reconnect the battery, toss a fuse back in and run the truck.

 

Curious if anyone else had run into this connector going bad.  I'd feel a lot better knowing the reason for the overheating.  

     

[schardein]

I'll just offer my opinion:

I wouldn't delete the connector.  Understand if you just need to get it running, but surely someone here can provide a replacement connector end for little cost.

 

Before making all repairs, I would put a fuse in and just "touch" each wire together to complete the circuit, one at a time.  If there is a problem further downstream that caused the melted wires, it may identify itself (fuse blows) so you can track it down.  If you reconnect all wires, then plug in the fuse and it blows, you are back to square one.

[coolwind57]

5 hours ago, schardein said:

I'll just offer my opinion:

I wouldn't delete the connector.  Understand if you just need to get it running, but surely someone here can provide a replacement connector end for little cost.

 

Before making all repairs, I would put a fuse in and just "touch" each wire together to complete the circuit, one at a time.  If there is a problem further downstream that caused the melted wires, it may identify itself (fuse blows) so you can track it down.  If you reconnect all wires, then plug in the fuse and it blows, you are back to square one.

Excellent recommendation on trying out each wire individually.

 

As far as deleting the connector, it appears to me that the only reason they have one there is for ease of initial assembly or manufacture.  I'm can't really think of a really good reason that one would need one there later down the road after the build.  I know that the C101 connector is notorious for causing trouble.  Is there any particular reason you recommend not deleting this connector?

 

If I'm correct, then the connector could be seen as a possible weakness--especially if perhaps the heat damage started as a circuit began to open as the connector loosened up  and lost good connection over time.  Or just got dirty and contaminated...it is occasionally near wet, muddy boots after all.  Buy hey, just a thought.  I acknowledge that I may be completely wrong here. 

 

  

 

 

[schardein]

4 hours ago, coolwind57 said:

Excellent recommendation on trying out each wire individually.

 

As far as deleting the connector, it appears to me that the only reason they have one there is for ease of initial assembly or manufacture.  I'm can't really think of a really good reason that one would need one there later down the road after the build.  I know that the C101 connector is notorious for causing trouble.  Is there any particular reason you recommend not deleting this connector?

 

If I'm correct, then the connector could be seen as a possible weakness--especially if perhaps the heat damage started as a circuit began to open as the connector loosened up  and lost good connection over time.  Or just got dirty and contaminated...it is occasionally near wet, muddy boots after all.  Buy hey, just a thought.  I acknowledge that I may be completely wrong here.

I think your reasoning makes sense, especially the point about the C101 connector.  I'm just a fan of not modifying the stock wiring at all, if possible.  I'd rather add a circuit than modify an existing one.  Any idea on what caused the meltdown?  It may have been just a bad connection inside the connector, but it's fairly common to see wires in that area (the kick panel) that have the insulation "nicked" to install alarms, stereos, or whatever- then that becomes a prime spot for a short circuit.

 

Quick story- my 91 XJ would die after warming up.  Checked codes- codes wouldn't read.  Bulb was blown.  Replaced, didn't work.  Started tracing wires, found several wires in the cluster harness melted together from an aftermarket stereo install by the previous owner (splicing wires into cluster harness, why?).  Replaced everything, read codes, replaced camshaft sensor, XJ has ran fine ever since (8 years and counting, fingers crossed).

[Minuit]

Connectors exist to aid serviceability/manufacturability, and sometimes to provide test points or "disconnect points" on the harness (for instance - the "Ignition Off Draw" connector that's present in HO harnesses is a single plug you disconnect to disable everything that could run the battery down in storage). In exchange for that, you do gain a tiny chance of the connector causing trouble. When using high quality connectors in the correct way, you minimize that risk to almost 0. AMC did not always use high quality connectors, nor did they use them the correct way. And they had the nasty habit of positioning them right in harm's way.

 

I really hate seeing connectors being arbitrarily deleted, and if I owned a C101 connector-having truck I'm not even 100% sure I'd delete it - I'd clean the contacts and pack it full of dielectric grease for sure - but cutting at wiring makes a shiver run down my spine just a little.

 

As to why I wouldn't delete that connector in particular, if I'm not mistaken you're referring to a grey 10-pin connector in roughly the vicinity of the parking brake pedal. That harness also contains oddly enough a Weatherpack connector... inside the truck, and is responsible for the dome lights and everything else leaving the cab of the truck towards the rear - fuel pump, tail lights, etc. I'm in the middle of hacking out the remaining floor rust in my 89, which just happens to be right about where that harness runs. So it's convenient to take that harness out so I don't have to worry about damaging it, and then plugging it back in if I need the fuel pump to work.

[coolwind57]

On 3/9/2021 at 10:27 PM, Minuit said:

I really hate seeing connectors being arbitrarily deleted, and if I owned a C101 connector-having truck I'm not even 100% sure I'd delete it - I'd clean the contacts and pack it full of dielectric grease for sure - but cutting at wiring makes a shiver run down my spine just a little.

 

Why did Jeep get rid of the C101?  One might assume because it was showing up as a cause of problems a few years later.  Or maybe it just cost less to build the harness without it.