Auto elec problem - not Subaru, sorry......

[Willie]

I have a '94 V6 Mitsubishi Galant that has developed a weired elec problem.

The "Check engine" light came on a while ago, but only dimmly. A couple of days later the battery was flat. Suspecting an alternator problem was my first thought. However, as the battery was under warranty, I decided to take the car back to the distributor who was able to test the system. He concluded that the battery was stuffed, so fitted a new battery and off I went.

Light was still on, so I thought must be alternator, but I got a new battery anyway!

Borrowed a multimeter from neighbour, and the alternator was charging at 13.7 volts. Two days later, battery was flat again. Took the car to Mitsubishi so they could hook it up to their diagnostic computer - no faults found, but light still on. I asked them to test alternator, as I suspected one or more of the diodes could be stuffed, allowing battery to discharge through alternator whilst not running (I still think this could be a possibility). They told me that it checked out OK, and couldn't find the fault, suggesting I take it to an auto electrician, as light still comes on.

When driving home from Mitsubishi dealer, the light went out. Have checked the car a couple of times since, and battery seems to be holding it's charge. (I haven't been driving the car, as wife is away and I am using Forester as it has the child seats in it.)

HOWEVER, when you start the car, sometimes the light comes on, and other times it doesn't. If the light stays on after the normal couple of seconds, I turn off the car and start it up again - this usually results in the light going out!

So, is this enough info for any auto elecs out there to give me a few possible causes to these symptoms? I need this car to be a goer, as I am driving the Forester to Sydney next Sat (16th), and wife and kids fly down a few days later - they need a (reliable) car here for those few days before they leave for Sydney.

Thanks for any help.

Cheers,