Subaru Legacy Electrical Problems

Hi all.

I have a 99 subaru legacy that I bought used about 2 years ago. I had it in indiana for 3 months, and drove it to/from work, with no problems. I’ve moved to seattle for grad school, and I don’t drive it more than once a week. If I don’t drive it for more than a week, the battery dies. I got a new one last winter. They tested the alternator too, and it was fine. The battery also seems to die faster in wet weather - it’s never a problem in the summer, but during the other wet seattle seasons, it can die after only a couple days of inactivity.

This wasn’t a huge deal, I just got a disconnect for the battery, and disconnected when i wouldn’t be driving for a week. Today I started the car, and I was driving down the road, and everything electric clicked off, the engine stopped, and then the electronics clicked back on. The engine didn’t come back on till I stopped and restarted it. It happened a second time after about 5 seconds more driving. I had made it about 2 blocks total, so I parked the car, and walked back home.

Lastly, the turn signals (on both sides) blink too fast, even though all the lights are good.


Seems to me 3 different problems.

  1. High electrical leakage (called key-off current) that discharges your battery. By the way, if this happens a few times, it damages the battery. This can be troubleshot with an ammeter and pulling fuses. key-off current is typically 50-100mA. Measure an hour after you turn off the key, as modules power themselves down after varying time delays.
  2. Sudden total electrical failure. Could be a wiring problem, other possibilities. If it is now permanent, should be easy to find with a voltmeter.
  3. Turn signal blinker. There is a doohicky near the fuse box that controls this in most cars.

Are you sure the battery is discharging when you let it set rather than just having a connection problem? It sounds like there is a bad connection somewhere in the main power buss but there may be two problems. If you don’t have a voltmeter and want to work on this yourself I suggest you purchase one. The money you save over a shop doing the repair on this pretty simple problem will pay for the meter. If you do get a meter make sure it will handle up to 10 amps for the current measurement. This will allow you to find out if there is a current drain problem.

To see if there is an excessive current drain on the battery you will need to place the meter in the current measurement function. With the car set as it would be parked normally and nothing turned on, remove the negative battery lead from the battery and then place the meter probes in series with the battery and the negative lead. Be sure the connections are isolated conductively from anything else. The meter will read how much current is being used. You may need to let the reading stay on for a few minutes to insure that the systems go into the “sleep” mode. You shouldn’t see more than around 80 milliamps (.080a) if the current draw is within normal levels. If it is more than that then you will need to pull fuses one at a time to see which leg is drawing the excessive current. Once you pin down the circuit you can then check the devices on the circuit and see which one is causing the trouble.

For the blinker problem the trouble may be with the flasher unit. See if the 4-way flashers work.


  1. When I first started having the problem, I bought a clip-on ammeter and checked this out. Key off current was around 125mA. High, but not (in my opinion) significantly higher. Because I can’t seem to predict under what conditions the battery drains, I can’t necessarily check key off current at a meaningful time. I could check it next time its really rainy, I suppose.

  2. Not permanent. It only occurred briefly when I was driving, and then everything came back on almost immediately.

it’s not a connection problem. When the car sits too long, there’s just not enough power in the battery to start. It cranks (weakly) once or twice, and then afterwards, it won’t crank anymore.

and I have a clip on DC ammeter that I used to attempt to troubleshoot the battery problem initially.

4 way flashers work correctly.

re 1, either, as you suggest, you have surges of higher current that discharge the battery, or the battery has been weakened so that 125ma for a week will discharge it. That calculates to 21amp-hours, indicating a very weak battery. Easy enough to check if you have a week. Or a battery tester.