Help Identifying a Wire

[PJ_10]

Hi everyone,

I have had multiple issues lately with an animal crawling up under the hood and chewing wires/building nests, and I'm working on repairing the damaged wires but cannot seem to find any info on one wire. I have attached a picture - it's in the same general bundle of wires that also splits off to the ECT sensor, and is a white/blue wire.

At least one of these wires was repaired/spliced by the dealer a while back, but it appears they may have just put some electrical tape over the chewed end of the white/blue wire. The only actual splice I can see is for the ECT sensor (green/red wire, also chewed). I couldn't find any info on this white/blue wire in the Chilton manual or anywhere online - any ideas? I can't even locate the other section of white/blue wire that I would be able to splice it to. Thanks for any ideas.

 

[Joe in NY]

Some manufacturers actually run all the wires for all possible options and some wires are completely unused. Ford does have some wires that serve no purpose because of the mountaineer/explorer common wiring harnesses.

I have a 2002 Ford Explorer Wiring Diagram book so I can help. Can you take a more broad picture of where the wires is located ? I can go look up which harness it is and then find a listing of all wires in the harness.

And is it a V6 or V8 ? 4X4 or 4X2?

 

[PJ_10]

I have a 2002 Ford Explorer Wiring Diagram book so I can help. Can you take a more broad picture of where the wires is located ? I can go look up which harness it is and then find a listing of all wires in the harness.

And is it a V6 or V8 ? 4X4 or 4X2?

It's a 2002 V6 4x4, and I just took another picture with the area circled in red - disregard the mess in there, I believe it was a squirrel that brought all sorts of grass and stuff in and chewed wires more than once. I have some other things disconnected such as spark plug wires but I am still in the process of repairing or replacing everything. It's mostly the one wire that is white/blue stripe that I was having trouble figuring out. Thanks for the help.

 

[Joe in NY]

I've got good news and I've got bad news.

Good news everyone! I found the wires!

Bad news everyone. Your car wont run with those wires like that!

16AWG WH/LB: 12V Ignition feed to coil pack
18 PK/WH: Coil 1 Ground to PCM. Cyl 6 & 2
18 RD/LB: Coil 2 Ground to PCM Cyl 4 & 3
18 DB/LG: Coil 3 Ground to PCM Cyl 5 & 1

How this works is the coil pack always has 12V when the key is in ON/START. The PCM then grounds each of the three coils accordingly to create a high voltage for spark.

 

[PJ_10]

Hmm, I will try to look at it more when there's daylight - the wire harness connected to the coils didn't appear to be damaged, but I could be wrong. It does not start at this point, or even crank, but I was thinking that could be due to a different wire for the starter relay being chewed according to some other information I had found and also the Chilton manual. It appeared that 5-6 wires had been chewed through in a few locations, in addition to the spark plug wires, so I was hoping that some splice repairs will get it running again. I really appreciate your help looking up the wiring diagram - I'll check out the harness to the coils tomorrow.

Edit - I just ran out and took a look, and the harness (and the bundle of the four wires) going into the coil pack appears undamaged as far back as I can see, but the damaged white/blue wire is actually in a different "branch" of what could be the same bundle of wires and might be that exact ignition feed that you mentioned. The damaged portion is closer to the ECT sensor and was in the plastic conduit along with the ECT sensor wires. I'm not quite sure where the other end of that chewed white/blue wire would be when it is running towards the ECT sensor. If I can find it, then it might be possible to repair the wire.

Is it possible that they would leave a sort of unused pigtail for what might be that same white/blue wire? Maybe it's for the ignition transformer capacitor and would be ok to leave as-is?

 

[imp]

@PJ_10
Here's what Ford lists for white/light blue, and ckt. #:

Module to Down Switch, 659
Sure track diagnostic, 606
C.B. volume control, 709
Temp. switch to warning device, 737
starter interrupt relay to neutral start switch, 900 ****
Vehicle maintenance monitor to oil temp output, 906
module to switch, 465
fused accessory feed #3, 294
electr. eng. contl. mod. to idle speed cont. motor #1, 264
RH front turn signal lamp, 2
Distributor electronic control feed, 20

You can obviously rule out most, consider a couple of them. imp

 

[Joe in NY]

The WH/LB does not run to the PCM with the ground/trigger wires. It runs off separately from the three to two different locations.

It runs from Fuse #38 in the BJB to the coil and on it's way to the coil there is a splice, the splice is still a 16AWG WH/LB and goes to a capacitor to absorb voltage spikes and noise.

Also, I suggest simply grabbing a multi-meter, setting it to continuity check, and test each side of the broken wire to the connector at the coil and to Fuse #38. That will let you know instantly

 

[PJ_10]

@PJ_10
Here's what Ford lists for white/light blue, and ckt. #:

Module to Down Switch, 659
Sure track diagnostic, 606
C.B. volume control, 709
Temp. switch to warning device, 737
starter interrupt relay to neutral start switch, 900 ****
Vehicle maintenance monitor to oil temp output, 906
module to switch, 465
fused accessory feed #3, 294
electr. eng. contl. mod. to idle speed cont. motor #1, 264
RH front turn signal lamp, 2
Distributor electronic control feed, 20

You can obviously rule out most, consider a couple of them. imp

Thanks - I'll check for any of those possibilities. Good thing is that I spliced the wires that were chewed and it starts and runs as it did before, I need to get a scanner to check for codes but so far it seems back to normal. I appreciate the info!

 

[PJ_10]

The WH/LB does not run to the PCM with the ground/trigger wires. It runs off separately from the three to two different locations.

It runs from Fuse #38 in the BJB to the coil and on it's way to the coil there is a splice, the splice is still a 16AWG WH/LB and goes to a capacitor to absorb voltage spikes and noise.

Also, I suggest simply grabbing a multi-meter, setting it to continuity check, and test each side of the broken wire to the connector at the coil and to Fuse #38. That will let you know instantly

I couldn't even locate the other end of the broken WH/LB wire, I did have other wires in that same area repaired by the dealer a few months back, I vaguely remember them mentioning that the car would still be fine without the added labor to repair one of the wires. Either way, it was chewed again but so far I just capped it off. I'll keep checking what you mentioned - thanks for the help with this.

 

[Joe in NY]

I recommend searching for a capacitor tied into the coil 12V feed. If it isn't there I highly recommend installing one. Not having one will lead to noise and voltage spikes which wont play nicely with all of the electronics in these cars.

 

[PJ_10]

I recommend searching for a capacitor tied into the coil 12V feed. If it isn't there I highly recommend installing one. Not having one will lead to noise and voltage spikes which wont play nicely with all of the electronics in these cars.

I'm still learning for sure but I enjoy learning how to repair my Explorer on my own if possible, so bear with me if I'm not great with the language everyone uses here, but I just found a Chilton wiring diagram from an online library access, and this (circled in red) is what I was thinking the broken/chewed wire is likely going to - the ignition transformer capacitor as you may be referring to. I could be completely wrong, but after soldering the many chewed wires with bruised arms, it's now running ok even without that broken connection although it's not ideal. I can't thank you all enough for the help. I'm going to check everything mentioned just in case.

 

[Joe in NY]

Yes that is exactly what I am referring to. It is a pretty important part for protecting the rest of your coil. High voltage discharge coils are not nice to electronics.

 

[PJ_10]

Yes that is exactly what I am referring to. It is a pretty important part for protecting the rest of your coil. High voltage discharge coils are not nice to electronics.

Thanks so much for that info - I am pretty sure the capacitor is still there, so I'll repair that connection ASAP. I really appreciate the help, I finally have my Explorer running again but this final repair will probably be what it needs.