Electrical issue

[i-wagon]

On the way home today my radio kept rebooting on me, hoping life would be simple I headed toward the womans folks house to get my factory radio. As I pulled on their road I had a battery light, abs light and airbag light come on, radar detector and radio were in constant power cycle. Got there and tested voltage off the suds on the alt per joel and got anywhere from 12.8 to 14.4 volts. Took alt out and had napa test it, tested good. Put it back in, checked all connections on the battery, had 14.4 with all lights on, rad fans kicked on and it went to 12.something. Napa thinks the battery is screwed up and trying to overwork the alternator, joel and I are leaning toward alt/ voltage regulator. Car is 07 imp, 1 year old optima red top. Thoughts guys?

 

[IBratmanI]

Alternator. I have seen alternators and starters for that matter "test out" fine at a parts store, but when replaced, all was good again.

 

[Chris]

Probably the alternator. Most of the time when they test them they don't really load them up. You're getting 14.4 output until you have a high load like a rad fan coming on, then it's taking a dump. That means it's failing under high load.

Before you go any further, though. check the grounds from the engine to the body, and engine to battery. Check the grounds at the battery for loose terminals or corrosion. Check the v+ wire on the alt. Make sure the nut is secured and the ring terminal and hardware aren't corroded and that the wire coming from the terminal isn't corroded.

Pull the fusable link to make sure there isn't an arcing connection in the fuse box, and check the positive terminal on the battery. A failure anywhere in there will cause intermittent electrical issues.

Keep in mind with alternators, they can put out enough juice to keep the charge light off, but not enough power to properly run the electrical system. A failing regulator or diodes is a bad thing.

 

[RBNasty]

I have seen faulty batteries cause funky problems as you describe. Very rare, but can happen. You could have the battery load tested to eliminate that right off the bat. If the battery checks out I'd certainly suspect the alternator. I had a ford explorer about 3 weeks ago that would randomly throw all the lights on in the dash then go back to normal. I found that when I revved it up the interior dome lamp would get exceedingly bright. That was far more obivous that the rectifier bridge in the alternator had failed (generally a smoked diode). Try loading the engine up and watching voltage as you rev the engine up. I'd certainly be more suspect of the alternator if you have had no starting issues with the current battery and all this cold weather. If anyone you know has adecent scan tool, generally overcharging will throw a code that will be stored in memory.

 

[i-wagon]

car doesn't start any harder than it always has (bought new) i have a hard time believing an optima crapped out in a year, but i've seen that too. the only thing i haven't checked that you guys reccomended is the fusible link chris suggested, and i'm planning on having advance load test the battery before i go home tonight since that's where i got it, and if it's junk they can warranty it. i'll post back later if i find it is the battery, if it isn't i'll plan on throwing an alternator in it after payday. looks like i'm running the fozzy till then. yay heated seats and mirrors!

Update: had advance do the complete electrical system test they do, battery tested better than it should, starter ok, alternator was just barely in the acceptable range, guess what I'm doing thursday...

 

[RBNasty]

An AC to DC converter device!!!

 

[Chris]

Starter test? Either it does work, or it doesn't work... It's one of those things that's fairly black and white... hah.

 

[i-wagon]

I was more interested in what the alternator put out under full load. Have a 110 amp rex alternator coming now

 

[SUBARUDE]

What Rex's comes with a 110 amp alternator?

 

[skipow]

literally just had this happen to me. new alternator/ cleaned battery leads fixed it.

mine tested fine at napa but i think these are the symptoms of a bad voltage regulator.

 

[Chris]

literally just had this happen to me. new alternator/ cleaned battery leads fixed it.

mine tested fine at napa but i think these are the symptoms of a bad voltage regulator.

Well they don't really load the alternator up when they test it. Just because it puts out 14.4 volts doesn't mean it'll put out full amperage without taking a dump.

 

[i-wagon]

I'll thinking voltage regulator too, it had spells where it would put out 14 under load, then drops for no reason

What Rex's comes with a 110 amp alternator?

Idk, napa listed it as 110 amp output with dohc turbo fitment. it looks identical to mine, just claims higher amperage

 

[i-wagon]

New alt and belt in, changed it in napas parking lot so I wouldn't have to pay the core up front. No warning lights, nothing acting funky. Only time the new one read low on my multi meter was when the hella 500s were on, i'll be checking the wiring on those later on, our maybe just ditching them

 

[Chris]

New alt and belt in, changed it in napas parking lot so I wouldn't have to pay the core up front. No warning lights, nothing acting funky. Only time the new one read low on my multi meter was when the hella 500s were on, i'll be checking the wiring on those later on, our maybe just ditching them

Read low at what RPM? At idle, an alternator doesn't put out nearly it's full capacity. It has to be revving fairly high to put out full power. So it's possible it idle it just can't keep up with the hellas. Rev the engine to 2k RPMs, and check again.

 

[i-wagon]

I'll have to have a helper. It was at idle, running heat full bore, fogs highs and lows and still had 14.4 volts