musicheadt

I'm not sure if my logic is right, so maybe you guys and gals can help me.

Car wont start. I can jump start it, and it drives fine. Battery is 5 years old, and seems to have good looking cells when I pop the caps off and look inside.
I cant turn on my headlights, and my instrument cluster lights are very dim, I tried hooking up my SCT tuner to my car to read any possible fault codes, and my car wont even power on the tuner.
My car has been sitting for almost a month, un-driven, un-started.

questions:

What should my alternator output voltage be?

I'm guessing my battery is bad, but I want to check the voltage coming out of my alternator before I drop 500 bucks, and time into swapping it out. If the battery wont take a charge, a new alternator isn't going to help me, and the battery is the cheaper immediate fix.

any help/suggestions would be appreciated guys!...

Nuke

Static voltage after sitting overnight should be in the 12.4v - 12.6 volt range. With a healthy charging system and battery with the engine running, it should be around 13.6v.

Looking into a cell gives NO indication of a battery's condition. Have the battery and alternator load tested. If you still have the OE MotorCrap battery, then you're way overdue. The batteries and alternators in the entire S197 line are prone to premature failure and a known weak link. Search the forum and you'll find tons of threads on this. If it helps, you're in good company.

Whitehorse10

Agreed, you need to take the battery out and have it tested at a local auto parts store if you want to. Personally I'd just go ahead and replace the battery because after five years you're due for a new one. Frankly I'm surprised a Motorcraft battery lasted that long. I think they usually die around 3 or 4 years. If you replace that battery and you're still having the same problems than you should start looking at the alternator. But it's not that hard to replace either.

musicheadt

Nuke and Whitehorse thanks for your help.

I picked up a new battery, but I haven't installed it yet.

I checked my battery with a voltmeter, that my Corvette buddy brought to me (thank God for car buddies) Battery was dead at 5.4 volts. We hooked his car to my battery for a while. We started my car and checked the alternator voltage, I had 14.5 volts on my alternator output.....so my alternator is good.

I ran the car at idle for about an hour, then ran some errands....turned it off, and restarted it a few times just to be sure the battery was holding a charge. Battery was at 13.1 volts with the car shut off....battery is good.

I picked up the new battery anyway, $95.00 is a small price to pay rather than miss a day of work. I can always jumpstart off the new battery in the morning if I have to, it's too dark outside to replace it tonight.

NOTE: I had a radio transmitter plugged into my cigarette lighter for 3 weeks while my car was sitting. These transmitters broadcast to your car stereo, and play mp3's, I think it was turned on for the last 3 weeks and just drained my battery down while I was out of town. (25 days)

After verifying my alternator was good, I don't think I will have any more issues, I will install my upgrade car battery tomorrow, and hopefully no more problems.

Another Note, I was shocked to find out alternators for our cars ran $500.00+...(around 650.00 installed, AFTER a core return, this is ridiculous!) .....my FRPP Duals didn't cost that much!.....

Once again guys....thanks for your help and fast response!...

Nuke

Don't bother checking the battery after it was being charged by the alternator for at least 12-24 hours. All you end up reading is the surface charge. Check it AFTER it sat for at least 12 hours. And 14.5 volts with the engine running is high. Either your alternator is overcharging continuosly or it's because of the battery condition. Put the new battery in.

tx_zstang

Battery. Mine lasted only 3.5 years.

Alec

I'm thinking I'm having a similar problem. It's just started to not want to turn over and make a repeated clicking noise, but it's only once in a while. I jump it and it starts right up and runs fine. I'm thinking I'm overdue for a battery

pascal

That's about what they last in hot States.

charlie32

Hi Guys. Remember---An Alt. is desighned to MAINTAIN batt. voltage NOT to charge a
dead batt. !! If you jump a dead batt--drive 10-15 min and then TRY to lay your hand on your Alt.---Is so HOT from overwork it will burn you. Always tricke charge a low batt for 21-14 hrs to bring it back to normal Do NOT try to regain the voltage by
trying to let the Alt do it !!

charlie32

Chg. #1 Trickle charge for 10-14 hrs.....