2010 Lucerne electrical - source discovered?
 

We just picked up a 2010 Lucerne, and have now learned (because we had to) about the recurring issue of the fuel pump relay burning out (literally burning). We are about to pick up the car from the dealership with a new fuse block and relay. From what I've read, we should expect this problem to happen again (and again and again).
The relay/fuse block are not the issue- they are the weak point in the system where the issue shows up. I have done a lot of searching, but I can't find anywhere that says what the actual problem is. Fuel pump? Battery ground? Gremlins? (actually, I'd probably take a Gremlin right now)
Has anyone seen or heard, via a blog or honest service tech, what the flaw is that vexes so many Buicks with this same problem?

Possibly with all such things as auto relays these days, are made in Mexico or China. With a burned relay I would say the coil short circuited. If the contacts were burned the pump would probably just not run or continuously if fused together.

The relay itself may be underrated causing the problem or maybe the coil is staying energized continously even when motor is not running (meaning not just pre start sequence) for some reason and over heating.

So it would have to be known the current draw of the pump and if wiring size and fuse match, also if the relay is rated to handle the amperage. Don't know if the "fuse wire" is still used these days, another problem when those burn out.

A simple way to test for a short circuit is to put a 12V lamp in series with the pump feed. If a short exists the lamp will light full brightness. If it's OK the bulb will be half bright and the pump would run at least for a little while. Corvettes (had an '87) for one would have their alternator regulation circuits something as that (single wire type alternator). Not charging would likely be just a bad dash light and it would light up if the filament was good showing problem existed.

Auto industry used alternator dashboard lamps that would glow red before amp and volt meters became the norm a lot of times.