Conductive rubber?

[Chuck41]

Here's a disturbing discovery. The fuel gauge was acting up and I traced it to an 83-ohm leak to ground somewhere in the sender wire. That seemed odd since the car has 100% new wiring harnesses. Adding to the oddity was the fact that turning on the headlights changed the gauge reading. I finally traced the short to the bundle coming through the firewall -- the one that has the pear-shaped cover on it. Now the fun part -- when the rubber connector for the sender wire was squeezed tight against the connector for the high beam indicator, a high-resistance short occurred. Check out the photo -- that connector has a resistance of 359 ohms from one end to the other. All the other black ones were similar, but the larger, brown connectors were not conductive. This is a new wiring harness from C&G.