Electrical Problems (XJ Related)

[Zenobian_84]

Sorry to post this in the MJ tech page, but I can't for the life of me find an answer to this question. I've even talked to a friend of mine who owned an XJ before, and they haven't a clue as to what's going on here with my '92.

 

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Bought the truck from a PO who told me that the fuses to the parking lamp / interior electronics (Laredo package, power everything, including antennae) needed to be replaced (among a few other odd and end things). Told him no big deal, and drove it home. After a bit of initial finagaling with things, found out that most of the fuses inside the junction block beneath the steering wheel were the newer kind, and not the older ones. Ended up replacing some fuses, and got most everything to work. However... upon further inspection, the PO told me that the power antennae motor would continuously run, so he had pulled the fuse for it to kill the power to the motor itself. Upon putting the fuse back in, I noticed that it would keep running while the truck was in the ACC / ON / Running positions. 

 

I decided to scope out the radio wiring, because it had all the tell-tale signs of a rush job (radio just limply hanging inside the stock hole) and found out he had tied the 12v constant (pink wire) with the accessory (purple and white) wires to the radio's main power feed, so that I'm assuming the radio would work as needed. Decided to clip the wiring to the motor inside the truck to eliminate the problem, as I could not locate the "White" power antennae wire that is "supposed" to be in the jumble of Chrysler's wiring harness. Got everything back to working properly as the factory intended, or so I figured.

 

What I have now found out is that almost all of the electrical components inside the truck will not work unless the 12v constant and accessory wires running to the radio are bridged together. If I undo those wires, I lose the power seats, interior lighting, power locks, power mirrors, and lord only knows what else. The truck is bone stock, and the only add-on I can see is there seems to be a factory tow-package installed back from '92, trailer wiring included. Tested the 12v constant wire inside the truck and discovered that it is not energized, at all, whatsoever.

 

Ran a diagnostic on the truck and it's giving me only a basic code, aside from a 21 that I fixed yesterday morning.

 

Code 12 - Battery input to PCM was disconnected within the last 50 key-on cycles (battery is bigger than stock size, apparently is "New" even though I've load tested it and it's a piece of crap)

 

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I guess then that my question would be what wiring hodge-podge did Chrysler pull here? I've never encountered any sort of shenanigans like this with any of the other Jeeps I've worked on or owned. Is this a common thing on the XJ's (or possibly MJ's as well), or is there some sort of sinister work going on here? I'm not even quite sure where to begin trying to sort all of this out, or what to possibly look into to see what's going on. The only thing I can think of is that there's a broken link somewhere in the 12v constant wiring in the truck's harness, and it's shorting out somewhere that's affecting the wiring to everything else electrical inside the truck. :hmm:

[HOrnbrod]

It's not a Chrysler problem; it's a radio hack job problem it sounds like. Is the radio aftermarket or non-original? If it doesn't have a power antenna pin the hacker who installed it probably used a 12V constant or switched pin for the antenna relay. That would explain the motor running constantly. Did you check all the fuses in the PDC? Swap around some of the relays in there (they are all the same), especially the ASD relay and see if anything changes. 

[Guest]

  On 6/7/2015 at 11:38 PM, hornbrod said:

It's not a Chrysler problem; it's a radio hack job problem it sounds like. Is the radio aftermarket or non-original? If it doesn't have a power antenna pin the hacker who installed it probably used a 12V constant or switched pin for the antenna relay. That would explain the motor running constantly. Did you check all the fuses in the PDC? Swap around some of the relays in there (they are all the same), especially the ASD relay and see if anything changes. 

Aftermarket radio. From what I gathered around the web, there should be a white wire inside the truck's wiring harness where the radio sits that controls the functions of the power antennae; but I cannot find it for the life of me. Everything else radio wise was hooked up correctly by the PO ( the radio had a wire designated for the power antennae, but was left unconnected), save for the power wires being tied together. 

 

Checked the rest of the fuses inside the cab and engine bay, with everything seemingly OK. Also, ASD?