mystery wire (new owner needs some help)

sidebrake · **Posted:** Mon Jul 12, 2010 10:25 pm

First, a quick intro: Hi, I'm Tom. I'm from St. Paul (Twin Cities), MN. I just bought an 05 KJ CRD with 52k miles and I'm thrilled so far. I'm no stranger to forced induction, but very new to diesel. I've been reading this forum for about 6 months prior to buying my CRD and felt like I made a very informed purchase... so a huge thanks to everyone here, including a buddy of mine who is a contributor.

On to my question...

The previous owner of my '05 spliced into the wiring harness at the top of the engine near the firewall and routed the wire to the ECU. Any guesses as to what he was trying to accomplish?? Should I attempt to rewire back to stock form?

Check out the blue wire:

Thanks in advance!

Tom

vtdog · **Joined:** Fri Sep 30, 2005 11:27 am **Posts:** 640

I believe that the hook up was to the flux capacitor, but it does not seem to be there in the photo

onthehunt · **Posted:** Mon Jul 12, 2010 11:54 pm

[quote][felt like I made a very informed purchase... /quote] :-)r

Sorry... I had to. Spliced wires into ecm done like that isn't a good sign.

tonycrd · **Posted:** Tue Jul 13, 2010 4:52 am

Maybe it's just a repair (poorly done)...

kdlewis1975 · **Posted:** Tue Jul 13, 2010 6:14 am

Brake controllers are fed power through a reasonably sized blue wire, though I wouldn't expect someone to run that to the ECU instead of intercepting the one under the dash. The only way to find out may be to unplug the wire harness and report the pin number for the wire. Could been for a SEGR install, but that should have a few more wires.

Rich · **Posted:** Tue Jul 13, 2010 8:46 am

I can't believe in the 4-pages of "what to look for" I emailed you, I didn't mention looking for an odd blue-wire... sorry dude :banghead:

I would agree, trace the wire into the ecu plug, and find the pin. Or just figure out the color scheme on the wire, and cross reference it with the FSM (check PM)

Welcome :POPCORN:

dgeist · **Posted:** Tue Jul 13, 2010 8:57 am

Instead of pulling apart the ECU loom, trace it to the other end. If it's not a stock repair, it'll go to some device somewhere else... like a brake controller, etc.

Dan

sidebrake · **Posted:** Tue Jul 13, 2010 9:18 am

onthehunt wrote:

Quote:

[felt like I made a very informed purchase... /quote] :-)r

Sorry... I had to. Spliced wires into ecm done like that isn't a good sign.

OK, fair shot. But, I've bought second hand modified vehicles before and one rogue wire wasn’t going to stop me from buying an otherwise solid Jeep. At this point, I'm not concerned, just curious... since it doesn't seem to be causing any issues.

I did check SEGR install info and it doesn't seem to fit the bill. I had hoped this would pop out to someone as obvious, but since it's not I'll see if I can do a better job of tracing the wire. Hadn't considered a brake controller, so I'll definitely look into that.

Thanks.

sidebrake · **Posted:** Wed Jul 14, 2010 11:55 pm

tonycrd wrote:

Maybe it's just a repair (poorly done)...

The wire is going from the cam shaft position sensor to the correct pin at the ECM. Nothing in between. Now I'm really curious as to why the stock wire was bypassed to begin with! Time to break out the multi meter...

mag03kj · **Posted:** Thu Jul 15, 2010 12:02 am

Remote crank?

rjmaype · **Posted:** Fri Jul 16, 2010 12:32 am

On my 7.3 Ford diesel, the cam shaft position sensor was a known gremlin component that after some age, would start failing with the engine just dying at no pattern which to diagnose.

They may have done the jump around wiring as a trial solution for some sort of engine dying.

kdlewis1975 · **Posted:** Fri Jul 16, 2010 7:17 am

There have been instances where wires in the harness managed to rub on something and become frayed. This may have been a repair for that.

Joe Romas · **Posted:** Fri Jul 16, 2010 9:17 am

kdlewis1975 wrote:

There have been instances where wires in the harness managed to rub on something and become frayed. This may have been a repair for that.

That was more on the 06 modles as the fuel filter assemblie was raised to clear the ESP/ABS brake thing.
The wires then hit the lower sharp edge of the fuel filter bracket instead of at the rounded edge of the bracket that's an inch or two highter up.

Those with an 06 should slit lengthwise a 3" piece of fuel line and put it over the sharp edge :jester:

Billwill · **Posted:** Sat Jul 17, 2010 10:20 am

I have had to bypass about 5 wires in my harness in my 2002 2.5 CRD as the original wires either had breaks in them somewhere or were going more or less to ground or were going more or less to something else. My Jeep had been in an accident so possibly the harness had been damaged somewhere but I could never see any damage.
I isolated the offending wires at both ends and replaced them. I have left copies of the relevant circuit diagrams with the changes I have made clearly marked under the rear seat so any future owner should be able to find my changes.
I also taped up my changes quit well so they are not so obvious. :BANANA:

mystery wire (new owner needs some help)

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