Engine Bay Re-Wiring

While upgrading the battery to an Odyssey 2150, I noticed a lot of crumbling conduit and a few melted wires, mostly along the positive side of the wiring harness. Since I needed longer power cables to reach the terminals I planned to use on the Odyssey I opted to rip out and replace the damaged wiring and conduit, then route them down a safer, cleaner path.

On the left side, the negative cable has been replaced with a longer, heavier gauge cable. The positive cables on the right are where most of the damage had occurred. With the three cables separated, the feed to the fuse box can be shortened about 8 inches and is no longer exposed to engine heat. The tangle of wires that splits before heading to the alternator and disappearing behind the engine can then be re-routed so that they experience less engine heat over less of their length. The positive cable that runs from the fuse box to the alternator was not damaged, so it was simply placed in new conduit and routed along a safer pathway.

With the larger battery in place, the stock battery cover will still close without issue. The cover’s function is also unaffected by the trimming done to the bottle jack’s storage area to get wiring through. To keep things simple, I’ve kept the stock wiring connected to a dedicated set of terminals on the battery.


With the damaged wiring repaired, the bottle jack out of the way, and clean cable pathways waiting I started on the additional wiring needed for lights, radios, and other equipment. Each of the large terminal connections have ports on them for two 8 AWG wires, one 4 AWG wire, and one 0 AWG wire. Currently, one 8 AWG connection runs through a 40-amp circuit breaker (where the bottle jack used to be) to a distribution block under the passenger seat. From there power feeds off to radios, accessories, additional interior lighting, and a future carputer setup I have planned.

The other 8 AWG connection powers a small distribution block also located where the bottle jack used to be. From there it powers rock lights, bumper-mounted flood lights, and will be used for other planned engine bay and bumper mounted additions. The 4 AWG connection runs through a 100-amp circuit breaker then straight up to a distribution block on the roof which is set up for lights and other equipment. Finally, the 0 AWG connection will be run to the rear of the vehicle to power the air compressor, fridge, auxiliary battery, and other equipment.