fudlub

Hey, everybody! I've got a 2003 Lancer ES, and I've been fighting this on-again/off-again problem for over 2 years now. I've tried a number of fixes, and I'll think I've got the problem licked -- but then, out of the blue, it'll come back. It's quite frustrating.

So basically, the problem is that -- occasionally -- my battery will drain overnight. Not completely, but just enough so that I don't have enough cold-crank amps to start my car in the morning. When that happens, I can start my car if someone gives me a jump -- or, I can connect a trickle-charger to my battery, let it sit for about 30-40 minutes, and it'll be good to go.

This issue, with the battery draining and the car refusing to start, will sometimes happen once in a month, after the car has been sitting all weekend. But sometimes it happens more often than that. This past week, it's been an everyday thing. So, perhaps the problem is getting worse.

In troubleshooting this problem, I have replaced my battery (twice). I have also replaced my alternator, which did test bad, according to the guys who tested it at Advance Auto Parts. I have also had all my belts replaced -- both serpentine belts and the timing belt -- not really to troubleshoot this issue, but just because they needed it. I have also replaced the positive terminal on my battery cable. The negative terminal seems to be fine; I've checked for corrosion and in fact have cleaned it several times just to make sure.

One other problem, which I think MUST be related to the battery-drain issue: Sometimes, when I turn off my ignition and pull the key out, the headlights and A/C fan don't die. They just keep running, and have to be turned-off manually. The radio and the clock die, however -- so that makes me think there's not a problem with the ignition switch. I would assume if the ignition switch was the issue, all the accessories including the clock and the radio would ALL stay on.

So, I'm guessing there's a relay somewhere that's gone bad? Does that sound like a likely assessment? Any guesses about where to look? And how do I test a relay to determine if it's bad or not?

fudlub

Alright, here's a new observation: When I parked my car and turned off the ignition today at work, the blower-motor kept running as usual, so I turned it off manually. Then, before I got out, I noticed a strange, intermittant, stuttering electronic "whine/buzz" coming from somewhere under the hood. It wasn't the first time lately I'd heard that noise, but this time I was able to pop the hood, get out of the car, and pinpoint where the noise was coming from before it stopped happening. And I believe it was coming from the Front ECU module, the MR515500, that big green box in the fuse-compartment.

It's funny, you can find those used or remanufactured for around $40, but if you buy one new from the dealership they want $240. When I asked the guy at the dealership about the price difference, he cautioned me against buying a used ECU, stating that there's some kind of computer they have to hook it up to to set it up for a specific vehicle. Anyone know if that's true? And if so, I'm guessing that I either have to pony-up the extra $200 for a new one, or ensure that the used one I buy is definitely from a 2003 Lancer ES?

Any thoughts?