glow plug harness - plastic cracked.

I cracked the glow plug harness in a couple spots in my 12yr old 2006 Jetta TDI, when trying to remove it to diagnose a recent glow plug fault code.

It's not a high voltage application, I'm thinking of just giving it a coating of goop or something similiar to weatherproof the cracks...

Any suggestions?

Glow plug fault code is gone - it was a break in a wire from the ECU to the glow plug relay.

If it were me, I'd just leave it as is until I replaced the harness.

All of the insulation foam or whatever it is crumbled and fell off of the wires to my glow plugs. The car still runs great, so I am ignoring this condition. I have a new replacement engine wire harness, but am tired of working on cars at present and will only address issues once they become a problem.

It's easy to make a new harness. It cost me around 15 dollars to do it on my '06, and that includes the beer. You'll need bullet connectors, 12 or 14 gauge wire, heat shrink and solder skills. I cut apart the whole harness and wrote down which color wires goes to which glow plug. The whole thing can be performed in a half hour or less. I used western union splices and grease as overkill to make sure there was a solid connection when splicing the harness.