My girlfriend’s 2009 Volvo S40 would not start this morning. We had been out of town for Labor Day weekend in my Corolla, so it had been idle for a few days, and there had been some rain (I’ll explain the relevance below). Her fob has been dead for quite a while now, so she’s been unlocking the car with the embedded key and triggering the alarm (yes, we’re those vilified neighbors), but all else has been functioning as expected. So this morning I hear the alarm going off repeatedly; she couldn’t get the car to start. The “key” (plastic fob) was turning through all ignition modes with no problem, but there was no ignition - no engine turn at all. Naturally, I suspected the battery was weak, so I tried jumping her off. Connecting the cables, I noticed the wipers went to full blast, and when she tried the ignition, there was a weak turn attempt (just one!). We let the battery charge up several times and tried again and again, but no dice.
Google has alerted me to two potential issues, both regarding the ECM/fusebox under the glove compartment: its wiring can come loose, and it can apparently get wet if the model has a sunroof (hers does). Both of these can apparently cause my exact problem, but neither of these things seem to have happened! All of the connections are snug on the ECM, and if rain made it through, I certainly can’t tell.
Anyone have any experience or advice here? I really don’t want to have to tow this thing to the shop!