My recently installed FICMrepair.com FICM fried last weekend and they’re saying a significant electrical event took it out. Alternator and batteries test fine, so I’m turning my attention to the wire harness. The area up around the FICM looks good, but working towards the passenger side I found some chaffing and split wires on what I believe is the harness for the crank position sensor. There is a shielded wire in this bundle and best I can tell is the wire inside the shielding is fine. Can I just wrap some foil material around this and tape it up? Obviously on the other wires I need to splice in new wire sections. Not sure if this type of damage justifies a complete harness replacement? Any opinions are welcome.

 

Foil tape is a lot cheaper than $500 for a new harness, but you'll have piece of mind with the latter option. How much is that worth to you?

 

I would just fix the problem area but that's just me. It depends on how well you can do the repair. You "should" do it by soldering new wires in but many people probably don't do that and just splice the wires together and use tape or some sort of connector and crimping tool. I can't speak about the foil portion of the wire but I'm sure it's important to use some new foil for that particular area to ensure it's done right.

As for the other wires, if you do decide to fix them, remember that you're going to have to go further than just these areas to do the repair in many cases. Many times, there is more corrosion or "burn" even further down the line that people don't see. And in some cases, it can be more than an inch or two down the line. Although somewhat "odd", I have seen wires that get corroded or damaged in an area and they look fine for many inches after that but then you take the rest of the harness apart and see that there are "spots" that are bad with overheated wires (bubbles) in them or cracks and other corrosion and it starts to look like wire cancer so by the time you're done, it was almost better to just replace the whole wire closer to the two end points and forget about the middle portion all together. Just saying to try to do a thorough inspection of the wires so you're not having more headaches down the road.

I'm sure others will chime in but one way to tell if a wire is bad in an area other than the obvious signs of being damaged or corroded (physical traits) is to "feel" the wire. If it's hard and brittle, then it's bad. If it's too "flimsy" or "rubbery", then it's bad as well as there will likely not be much left underneath the coating with wires being corroded (that you can't see). I guess in other words, get used to the "feel" of a wire. If it's not the same "feel" as a wire, then there's likely something wrong.

 

Damn, you have work to do.

 

Or money to spend. At least he has a choice this time.

 

Well, got it patched up. Cleaned everything with electrical contact cleaner and the wire inside the dry rotted insulation was surprisingly good. Still copper in color, solid and no corrosion. I ended up just cleaning everything up, wrapping each wire individually with self fusing 500 degree repair tape and foil tape wrapping the one wire, then wrapped the whole bundle in Tesa tape. Laying the harness in position it’s clear where the chaffing was, the valve cover stud right behind the alternator. I kind of rerouted it down further to keep it away from that stud. Not sure this is the permanent repair, but it should work for now. No crank position sensor error codes so it’s at least working. The boys at FICMrepair.com say that harness is on back order anyways.

We’ll see how long it holds up, or how long I own the truck….

 

What particular foil tape did you use on the crank sensor wire?

 

I positioned the factory stuff as best I could, which did a pretty good job for coverage, then wrapped in “Cool Tape” from Autozone. Here’s a pic of both the self fusing tape and the cool tape.




Here’s the completed repair for now.

 

for what its worth, I would have done the same without blinking an eye. If its good, leave it. If not, solder splice with new high quality shrink wrap. Rewrap the sensor wire with foil and rock on.