Does anyone know the purpose of these cables in the trunk?

Grounding straps

The cables are just under 5 mm in diameter. I can turn them at the mount point at the bolts with very little effort - both sides. I wouldn’t say the connections would rattle, the they are in no way tight.

It's backup, emergency ground in case your main ground springs a leak. That's why it's in the trunk. That reminds me, it's almost that time of year to change your inflation from winter air to summer air. Cheers.

Yep - they are the ground for the power lock and release button. One side of the hinge may not be grounded at any moment so the did both sides. Probably overkill to wrap them in steel, but keeps them from being cut by accident.

My GUESS is that these are safety straps. These are WAY too big (read as "expensive") for them to be ground straps. Plus, they don't actually ground anything. They lead from under the cover to the moving part of the hinge. In order for these to work as ground straps, they'd have to lead from under the cover to the stationary portion of the hinge.

I wonder if you accelerate the Ridgeline up to highway speeds with the trunk lid open if the air does an unexpected trick. I know that in pickups with the tailgate closed that the air forms a relatively high pressure bubble in the bed that serves to deflect oncoming air out of the bed, which is why your fuel economy isn't significantly higher with the tailgate down. In this case, I wonder if that swirling pocket of air would actually apply pressure on the BACK side of the trunk lid when open, trying to tear it off. Hence the safety straps.

Nervey said:

It's backup, emergency ground in case your main ground springs a leak. That's why it's in the trunk. That reminds me, it's almost that time of year to change your inflation from winter air to summer air. Cheers.

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In El Nino years we change from winter to summer air on April first. It let’s us get a jump on the hot weather. 🤣

It is a conundrum. I would take off the snap fasteners on the plastic cover to see what the cables attach to, but I’m afraid I’ll break them. Break the plastic fasteners that is, not the honking 1/4 inch thick steel cable. I’d bet the cable could support 1000 lbs. 🤣

Ground straps can never be loose like these cable are. There is a voltage drop across anything except a tight connection.

Nervey said:

It's backup, emergency ground in case your main ground springs a leak. That's why it's in the trunk. That reminds me, it's almost that time of year to change your inflation from winter air to summer air. Cheers.

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And don’t forget to change your blinker fluid!

Zigzagman said:

And don’t forget to change your blinker fluid!

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Is SAE okay or does it have to be metric? I can't find amber and I don't know if clear is DOT approved. (sorry, couldn't resist)

SAE blinker fluid, metric is for the Canadian models.

zroger73 said:

Honda refers to this an an anchor cable. Part number74840-T6Z-A00 is located in the parts diagram under wire harness. It does appear to keep the trunk lid from flying off if the bolts come out or mounting points break off.

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Cool. Thanks! 👍 Was that in the service docs?

Yes.

Spidey said:

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ID-10T. LOL. You assault me with laughter. I had trouble breathing there for a minute.

Could be a ground for static electricity.

Brucemeister said:

Could be a ground for static electricity.

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You apparently did not read post #13.

You're right, must've skipped right past it.