I'm going nuts on this one...

A friend's '06 Tucson dies in my driveway the other day. Seeing as they don't have a ton of cash, I offer to look at it for them. I turn the key, the fuel gauge doesn't work and the pump doesn't run (they're the same unit). So I replace the fuel pump because that's obviously the problem, right? Wrong.

After I put in the new pump, the fuel gauge started working again, but the pump still doesn't run and the car obviously does not start. I jumped a wire directly to the pump from the battery it runs fine. There's no power at the pump harness, but there's power at the relay under the hood. I swapped relays to make sure that wasn't the issue, and still nothing.

Ahhhh!!! Any input guys? This one has me stumped. At this point, I'm thinking it has to be something related to the immobilizer. The check engine light wasn't on before, so I haven't checked for codes either.

Odd. Usually the individual parts of a Hyundai out last the car as a whole. I would have said relay, but you said you checked it. Can you run a jumper from the relay to the pump and get it to work? Could be a bad wire.

Im sorry but i have to criticize your decision to replace the fuel pump first.

Posted by big dave Im sorry but i have to criticize your decision to replace the fuel pump first.

That's alright. I don't disagree.

Posted by jeepdave Odd. Usually the individual parts of a Hyundai out last the car as a whole. I would have said relay, but you said you checked it. Can you run a jumper from the relay to the pump and get it to work? Could be a bad wire.

Yeah, I tried that. The pump runs fine with power directly to it. Car still doesn't start though.

Sounds like an immobilizer issue... Hyundais are a little notorious for that.

Turns out the culprit is a bad wiring harness.

I lol'ed when the dealership told her she needed a new fuel pump though.