1969 Barracuda Dome Light Question

Have you tried contacting M&H? They make perfect reproduction wiring harnesses for classic mopars. The M&H harnesses are sold by Year One.

Reproduction Wiring Harnesses for America's Muscle Cars

I see "rear lamp harness Barracuda Fastback" in their catalog. Not sure if it has the dome light harness you would need to contact them and ask.

Evans is another source. I bought AC and Trans harness from them years ago. Quality not as good as M&H but can make harnesses that are otherwise not available:

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