Hi folks,
On the home stretch, nearing the finish line. The decision is to put a new set of blower-end connectors on my test cable, with the cross-connect of the two supplies as discussed earlier. This keeps the car as close to original as possible, but with the cross-connect to aid in keeping the two sides balanced. I'm leaving the PEM-end of the test cable as-is. I've been measuring the current from both supplies during the daily top-off charge, and it appears to be performing well. Overall, this final design minimizes any changes to the original wiring harness (the change is fully reversible), maintains use of the progress so far, and is the easiest to complete. Basically, I'm replacing the PEM-to-Blower part of the original wiring harness with a slightly better one, and with new connector parts.
Mouser delivered the new AMP connector housings and new 0.250 female F connectors (571-344081-1 and 571-344009-1-LP, respectively). Turns out that the connectors do not come with the white plastic end caps, nor the foam weather inserts that go around the wires. I have no idea what to order, so I'm re-using the end caps from the original connectors, and have "adapted" some foam earpieces for the task of keeping the weather out.
I also picked up a 1/2" split wire loom from the home improvement store for protection of the wiring harness. That slipped easily over the wires, and was anchored in place. The harness goes up the right hand side to near the back corner of the PEM, well away from anything moving. It's held in place on the upper end by a tie to the wiring that goes to the ABS fuse holder, and on the bottom by a tie to the corner access hole, and a cable clamp with a short screw through the bottom of the trunk. Since I will lose electrical monitoring access once the connectors are attached, I added another set of wires going down in parallel with the power lines. It terminates with a PowerPole connector at the PEM end, and joins the power feed at the cross-connect splice. That gives me access to monitor the voltage (but not current, sadly) at the motor end, and also provides a back-up way to feed power to the blower should the PEM-end connector fail yet again.
All the wires are spliced together under the car: two going to the pair of new AMP connectors, and three coming down from the PEM (two from the PEM, and one from the PowerPole). Kind of a bigger lump than I had intended, but I'm tired of looking for other ways to connect stuff. The wires are insulated with heat-shrink tubing (the kind with glue on the inside), and another layer of electrical tape. If I had this to do over again, I would stagger the two splices, to keep the overall lump smaller.
The new ends of the cable are then attached to the original motor-side connectors to feed the motor, and secured to the underside of the car with another cable clamp.
All this done, I let the car do its daily top-off charge, while monitoring the voltage from above. It completed the cycle in an identical manner to what it's been doing recently, so the new cable is behaving well.
YAY! Almost done.