The PO seems to have left the harness almost completely intact, other than a redneck job on the aftermarket stereo (no crimps, no solder, just twist & tape. He also wired in a switch for the LED halos, and he did such a hack job on that all we had to do was pull the wire out of the fuse socket he jammed it into. But this one thing under the hood has me baffled.
For the record, this is an 02 4.0L auto, in case you want to follow along at home with the wiring.
At the gray PCM connector C3, the WT/DB wire is cut. Further back in the harness, behind the valve cover, this wire was also broken. That's probably why he cut it here; he didn't know where it was broken at. Coming out of the PCM connector that WT/DB is spliced to what looks to be a GR/OR wire. Bad lighting plus dirt & faded over time is hard to tell the exact color. It could be DG/PK. Hard to tell. That WT/DB wire comes out of the PCM and splices into the GR/OR and then goes to the alternator. This kind of makes sense, since that WT/DB shows to be the Generator Source (alternator?) on that connector in the FSM.
The other end of that broken WT/DB wire is the confusing part. We traced it. It goes to the temp sensor. On the FSM, the temp sensor has 2 wires: TN/BK for the signal and BK/LB for the sensor ground. One of my wires on the temp sensor is absolutely a WT/DB. IDK why I didn't continuity test to prove it is the same wire, but let's face it: It's the same wire. Aside from it being cut, it looks to be 100% factory that the Generator Source pin on the PCM goes to the temp sensor. Makes no sense. And regardless, the wire itself was broken on it's way back to the PCM. Makes you wonder how the temp gauge was actually showing anything! Also why he was getting "engine not up to temp" codes.
Now the GR/OR wire that is spliced in and goes to the alternator.....that sort of wire is OEM just by looking at it, and it's probably 14ga. But it might be regular green, or maybe dark green? And the trace...it could be orange, or maybe pink? A 14ga GD/PK would be the ASD relay from that same C3 PCM connector. I haven't yet explored that C3 bundle to see if there is a similar 14ga green & whatever color wire hiding in there, cut or spliced to who knows what. Counterpoint: When we turn the key we feel the ASD relay click, and then click back ~2 seconds later. So it certainly appears to be working a-ok.
We're a good way into the harness and it's evident bubba never got into the meat of the wiring, except to possibly re-crimp the end on the brown starter wire. There is no evidence that he ever touched it, much less f'd up anything other than what I've mentioned. But more importantly, I'm at a loss how the ASD & temp gauges worked, and I guess how the alternator can somehow proxy for the ASD circuit.
For the record, this is an 02 4.0L auto, in case you want to follow along at home with the wiring.
At the gray PCM connector C3, the WT/DB wire is cut. Further back in the harness, behind the valve cover, this wire was also broken. That's probably why he cut it here; he didn't know where it was broken at. Coming out of the PCM connector that WT/DB is spliced to what looks to be a GR/OR wire. Bad lighting plus dirt & faded over time is hard to tell the exact color. It could be DG/PK. Hard to tell. That WT/DB wire comes out of the PCM and splices into the GR/OR and then goes to the alternator. This kind of makes sense, since that WT/DB shows to be the Generator Source (alternator?) on that connector in the FSM.
The other end of that broken WT/DB wire is the confusing part. We traced it. It goes to the temp sensor. On the FSM, the temp sensor has 2 wires: TN/BK for the signal and BK/LB for the sensor ground. One of my wires on the temp sensor is absolutely a WT/DB. IDK why I didn't continuity test to prove it is the same wire, but let's face it: It's the same wire. Aside from it being cut, it looks to be 100% factory that the Generator Source pin on the PCM goes to the temp sensor. Makes no sense. And regardless, the wire itself was broken on it's way back to the PCM. Makes you wonder how the temp gauge was actually showing anything! Also why he was getting "engine not up to temp" codes.
Now the GR/OR wire that is spliced in and goes to the alternator.....that sort of wire is OEM just by looking at it, and it's probably 14ga. But it might be regular green, or maybe dark green? And the trace...it could be orange, or maybe pink? A 14ga GD/PK would be the ASD relay from that same C3 PCM connector. I haven't yet explored that C3 bundle to see if there is a similar 14ga green & whatever color wire hiding in there, cut or spliced to who knows what. Counterpoint: When we turn the key we feel the ASD relay click, and then click back ~2 seconds later. So it certainly appears to be working a-ok.
We're a good way into the harness and it's evident bubba never got into the meat of the wiring, except to possibly re-crimp the end on the brown starter wire. There is no evidence that he ever touched it, much less f'd up anything other than what I've mentioned. But more importantly, I'm at a loss how the ASD & temp gauges worked, and I guess how the alternator can somehow proxy for the ASD circuit.
