Couple weeks back I was coming back from a short trip of about 2 hours driving, and while on the highway flashed my high-beams, and the car kind of stuttered, the radio blipped for a second and a few warning lights came on. This happened a few times, never for turn signals, just the headlights themselves. After getting home, the CEL read something about ECU power/voltage.

After shutting the car off to clear the code and see if it returned, the car acted as though the battery wasn't there at all, completely dead. Stayed that way for about 5 minutes, then started up normally except for the radio security feature.

Fast forward to today, a chilly morning. My first drive of the morning, of about an hour's run time, went fine, except for some power steering noise. I get home and again the car acted completely dead, no response except a soft thunk when trying to remote lock the doors. Battery had voltage, but the car didn't see it. After about 2 hours of fiddling with fuses and testers, I was sitting in the car with the key in "On" when the car suddenly lit up again like normal, but again with the radio locked.

Any idea of what could cause this, and how to fix? I'm scared to take the car anywhere in case it decides to play dead again, somewhere less convenient than my driveway.

 

Pretty good bet you need a new positive battery cable. My 2006 Acura TL, built on the same assembly line as your Accord, and uses many of the same parts, had all manner of electrical issues a couple years back; I bought a new battery (which it needed anyway) and the problem didn't go away. One morning the car was acting funny and I went out and played around with the cables to see if they were loose following the installation of the battery; they weren't, but the problems went away for a few days. I bought a new OEM battery cable (cost me roughly $40) and put it in, and didn't have an electrical issue for the next three years, right up to when I traded the old girl in a month ago.

 

If you have a volt meter, measure the battery voltage with the engine running across the battery posts. Also measure the voltage at the red wire at the fuse box to the negative battery post. Post the readings you get. It could be a bad battery, alternator, or battery cables. I highly recommend to not use the lead battery terminals you can get at most parts stores.

 

I'll look into that part, was it a very involved swap?

 

Not terrible, but small hands definitely help.

 

I do not have small hands, but I'm reasonably seasoned in reaching into small places anyways. Do you recommend replacing both cables at the same time? Looks like it's only $5 more to get the negative cable off RockAuto as well.

 

As far as I remember I don't recall anybody having an issue with the negative cable; just the positive.