Explorer Terminal 30 Error

I had a similar issue with my Explorer. Have you checked for any voltage drops across the fuse box? A faulty circuit breaker could also be the culprit, especially if it's intermittent.

Voltage drops... fuse box... circuit breaker... Okay, you're speaking a language I only vaguely understand! Where exactly should I be sticking my multimeter to check for these voltage drops? And how would I even know if a circuit breaker is faulty? Is there a specific one I should be looking at?

Honestly, without proper diagnostic equipment, it's tough to pinpoint the exact location of the fault. Given the continuous plus interruption and the poor starting, and since you're not familiar with deeper electrical diagnostics, I'd recommend taking it to a reputable workshop. It sounds like the battery is heavily discharged or defective, but better have it checked by a professional before messing anything up.

You were right, it was beyond my capabilities. Took it to a workshop and they found a faulty circuit causing excessive drain, which was killing the battery. Repair cost was 290€. I really appreciate you pointing me in the right direction!