Washing a harness

I just got a new (used) engine wiring harness for my MR2 to replace the one that's dry-rotting on me. The new harness is in great shape, but filthy. If I dunk it in a bucket of soapy water and gently scrub it off—assuming it dries completely before I install it—there shouldn't be any harm in that, right?

jg

I would wonder about:

A- Connectors- water inside the connectors in voids that have a hard time drying out, and

B- If the harness is sheathed, water could get inside the sheathing, and pool there for a long time.

I'd be a little more careful about the dunking. Instead of full submersion, can you dip individual loops one at a time and rag wipe it one section at a time (keeping the connectors and sheathing ends out of the water as much as possible)?

If you submerge the connectors, I'd first spray them with WD-40, then dry them out carefully after (shake out water, then use a hair dryer).

I think you're fine. I'd wait until after cleaning it to spray WD-40 in the connectors, after all that's what it's really for (water displacement.)

What I'd do:

1. Unwrap it.
2. Clean with WD40
3. Clean WD40 off with dish detergent / water. Take care to avoid water in the connectors.
4. Air dry for a couple of days.
5. Re-wrap it.
6. WD40 in the connectors.

If you don't want to go through all of that, Purple power mix and a scrub brush will get you most of the way there. Still follow up with a WD40 squirt in the connectors, and probably something like armor-all on what's left of the original wrap.

Goop style waterless hand cleaner is good for cleaning rubber and plastic bits, if the jacketing of the harness is non porous it will probably work well for that to. I take a blob of it in a rag and work it in, then chase it with a dry rag to wipe it all off.

What I do at work is lay down a 4'X8' sheet of peg board on sawhorses. I then lay the harness on that and zip tie it down in random sections. Then I can unwrap, clean and re-wrap sections at a time. Any sockets, switches and connectors go into an ultrasonic cleaner. The rest is wiped down with brake cleaner and rags (carb cleaner ad WD40 will sometimes destroy the tracer colors on vintage wires). Anything that went into the ultrasonic tank gets meticulously blown dry and then the harness is re-wrapped with the Testa cloth tape from the BMW dealership