OK gang, strange question time. I *think* the answers are going to be diesel-specific, but if I don't get an answer in a few days, maybe a mod can move this over to the generic Super Duty forum.

The truck in question is a 2005 F-350SD 4x4 CC SWB PSD XLT Sport.

Question 1, the easy one: Does anyone know where the ground cable from the driver-side battery terminated/is bonded to the frame? I'm installing some serious power-hungry accessories, and would rather bond to the point on the frame rather than directly to the battery. (Yes, there's a reason... if the bonding from battery negative to chassis ground fails and you hook equipment directly to the battery, the engine may try to crank "through" the equipment as they are bonded chassis--battery and would present ground potential. This tends to release the magic smoke from things, or worse. Seen it happen...)

I've tried to look for the grounding point, but it's pretty hard to trace considering where it runs.

Question 2: I also need a way to pass large wire through the firewall. 2 runs of 1/0ga., 2 runs of speaker wire (siren speakers), 6 runs of 18/4 jacketed (LED lightheads), etc. Under the dash, slightly above where the big wiring harness (presumably from the computer) runs, there is a "flap" in the acoustic material which exposes an easily-accessed hole of about 2" diameter. There are also two smaller holes on either side of the big hole, suggesting to me that there may be a snap-in grommet/ring to protect wiring running through there. Does anyone know a. what's supposed to run through this hole and b. if there's such a grommet/ring available? Part numbers?

Thanks!

 

I'll give this a shot -

Q1 - can't you just bond your ground anywhere on the frame that is convenient? If the battery connection is that difficult to locate, then installing another connection there won't be easy either. Besides, since the frame is all metal, you shouldn't have any issue with potential differences since the battery is already connected there.

Q2 - I'm assuming you have an automatic transmission - sounds like the hole in the firewall where the clutch goes through. I don't know of any pre-made grommets, but you can make your own fairly easily.

Hope this helps!
Jim

 

Yeah, I can, but I want to avoid drilling the frame, a. because it would be tough to do and b. because I'm not certain what it would do to the frame's integrity.

That's my guess on the passthrough. I just wanted to see if there was a grommet already in existence.

 

don't worry about drilling the frame, just find yourself one of the 5000 unused holes that already exist in our frames.