I had an issue with my last hilux (1994). For a while it felt like the battery would drain overnight, but then if i jumped it in the morning it would start first time for that day, then same again tomorrow. Battery place told me there was little to no drain on the battery, and the battery wasn't the issue. Then it stopped starting even with a charge pack connected. I reco'd the starter motor (which needed it) and it worked for about a week, then same problem. Housemate is a mechanic, identified faulty relay. (Top right hand corner of engine bay, right in front of passenger seat.) It worked for a few days, then same. Performed a full service with a wire brush over all exposed points tracing back from battery, Found a wire that had been earthing out, that looked like it may have been connected to a spotty that was removed, but left the wire behind. Taped and secured the wire - Started first time every time from then. Probably a combo of all steps, or maybe just the wire, but that's how i went about it.
