Odd electrical problem ('69)
Thread Starter
Heel & Toe
Joined: May 2021
Posts: 20
Likes: 28
From: Pasco, WA
Odd electrical problem ('69)
I took the car out Friday evening, and when I drove home, it was stuttering on acceleration and the lights got progressively dimmer. It nearly died on my street as I went to back into the garage, then did die in my driveway, with headlights no brighter than candles. Trying to restart to pull into garage didn't even click the solenoid. Was assuming alternator went out and I'd killed the battery with lights & heater on.
10 minutes later, I checked the battery and it showed 11.9V, i.e. low, but not "nothing electrical will work at all" low. I threw a charger on it for 10 minutes and then it started right up and I pulled it into the garage. Yesterday it started/ran fine.
Any ideas?
10 minutes later, I checked the battery and it showed 11.9V, i.e. low, but not "nothing electrical will work at all" low. I threw a charger on it for 10 minutes and then it started right up and I pulled it into the garage. Yesterday it started/ran fine.
Any ideas?
Melting Slicks
Joined: Aug 2016
Posts: 2,337
Likes: 1,165
From: CLEVELAND STUCK IN OHIO
2024 C3 of the Year Finalist- Modified
Your first guess,,,,, I’d replace the voltage regulator, pretty cheep and easy to do, most local parts stores have them in stock.
.
Hopefully your gauge was telling you the same thing,,(if it’s working),,,
.
.A easy place to start,,,
.
Hopefully your gauge was telling you the same thing,,(if it’s working),,,
.
.A easy place to start,,,
Burning Brakes
Joined: Jul 2018
Posts: 979
Likes: 258
From: Maryland
i would check to see if the alternator is keeping the battery charged properly. With the car turned off, put your multimeter in the volts position and check the DC voltage. Place the positive (usually red) lead on the pos terminal and the negative (usually black) lead on the negative terminal - should be in the 12.2 - 12.8 range. Now start the car (with no accessories running) and check the voltage - should be in the 13.8 to 14.2 range. Now turn on the lights and you should see a slight dip and then the voltage go back up - indicating the regulator is doing it's job. On my 69, the regulator is integral to the alternator. Now if all this checks out, you should be good to go in this area. If not, have your alternator tested at a shop or replaced.
If you replaced the battery and the issue was the alternator or the integral regulator, the battery will die again.
If you replaced the battery and the issue was the alternator or the integral regulator, the battery will die again.
2026 Loser of the Year
Joined: Sep 2013
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From: New Or-leens Loo-z-anna
Melting Slicks
Joined: Aug 2016
Posts: 2,337
Likes: 1,165
From: CLEVELAND STUCK IN OHIO
2024 C3 of the Year Finalist- Modified
.
If you did all this,, you just did the alternator test.. so,, if its not putting out properly, it tested bad, , ,
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.Your Guage on the dash should be telling you the same thing,,,, [ if the Guage is working properly ]....
Burning Brakes
Joined: Jul 2018
Posts: 979
Likes: 258
From: Maryland
Your right - if it fails those tests outlined it probably is time to get a new alternator.
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I took the car out Friday evening, and when I drove home, it was stuttering on acceleration and the lights got progressively dimmer. It nearly died on my street as I went to back into the garage, then did die in my driveway, with headlights no brighter than candles. Trying to restart to pull into garage didn't even click the solenoid. Was assuming alternator went out and I'd killed the battery with lights & heater on.
10 minutes later, I checked the battery and it showed 11.9V, i.e. low, but not "nothing electrical will work at all" low. I threw a charger on it for 10 minutes and then it started right up and I pulled it into the garage. Yesterday it started/ran fine.
Any ideas?
10 minutes later, I checked the battery and it showed 11.9V, i.e. low, but not "nothing electrical will work at all" low. I threw a charger on it for 10 minutes and then it started right up and I pulled it into the garage. Yesterday it started/ran fine.
Any ideas?
put the battery on an auto charger overnight. Next day check the voltage, if 12.5 fire it up and check the voltage at the battery running. It should show 14.5v. If it’s 12.5 or less you can assume the alternator may not charging. Still the alternator may be ok so clean all your grounds and positive contacts from the alternator back to the battery. Check it again, still 12.5 check at the alternator. If the alternator is putting out work your way back to the battery.