[Christopher Robben]

I have a 2005 Forester 2.5X (the non-turbo) and have had intermittent battery/alternator issues for the past few days. I just got back from a six month military deployment to find that my Forester is very much resentful of me being away for so long. For starters, the AC compressor belt and the tension bearing were missing. After fixing these, troubles with acceleration popped up. Took the car to Subaru and they put in new signal coils, new spark plugs and new wiring. $650 gone.

As I was driving back, the brake and battery lights would come on intermittently. I chalked it up to them disconnecting the battery and figured it would go away, which it did. A few days later and now the brake, battery and ABS lights are coming on. The lights are dying at night and twice, it has felt like ABS has actually kicked on (car jolted as if I had hit something). What is strange is that everything went away the next day and the car ran fine for about 20 miles. Then, just the battery and brake lights came on. Voltmeter is in the midway range and either way, both the battery and the alternator are less than a year old, plus both tested good voltage-wise.

The only thing I have found is that the battery ground cable has the shielding pulled back and the wires are touching the starter solenoid where the ground post is. I don't know if this could be causing the battery to be losing ground or not, but any guesses would be appreciated. Since this happens intermittently, it makes me think wiring has to be an issue, but I don't know for sure. Any ideas?

 

[plain OM]

The large (negative) ground cable from the battery should go to a bolt on a bracket near the starter. The wire of the cable itself should not be touching anything other than the round terminal at the end of the cable that's held down by the bolt.

When the brake and battery lights come on together, that usually indicates that the alternator has stopped working. If you are monitoring the system voltage with a voltmeter, normally with the engine running it should be around 14 V. When the alternator stops working, it will drop down quickly to around 12.5 and continue to go down as the car is driven.

There could be a bad connection in the charging system, perhaps a loose connector at the alternator. But, is the alternator a genuine Subaru one, or an aftermarket replacement? There are frequent reports here of problems with generic replacement alternators, especially so-called rebuilts.

Also, if the AC drive belt and tensioner were missing, then it would appear someone was in there to get parts. Is the alternator that's there now the one that was there before you left? (Incidentally, did they have to break in, or was the car unlocked?)

 

[Christopher Robben]

I had the car in storage, so I just assume that the AC belt broke off sometime before I left. That's what I meant by missing; the belt was completely gone. It was winter, so I would not have noticed it since I didn't run the A/C. As for the Compressor tensioner, it was made of plastic and was melted in half. No reason for me to assume the alternator was taken off. As for replacing it, I bought an alternator from Autozone, not straight from Subaru. Only started happening after it had been taken in for the acceleration problem, so wondering if something was bumped connection-wise.

Thank you for the response. Definitely more stuff to look into.