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alternator over charging? see pics.

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alternator over charging? see pics.

Old 02-13-2013, 08:42 AM
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alternator over charging? see pics.

Hi all. The truck is a 20 yrs young 22re pickup, and still fun to drive. Having a charging issue though. The battery light/ parking light have been flashing at me. I cleaned all my connections, and the lights started flashing more frequently. My multimeter shows about 13.2v when not running, and cycles between 14.3 and 15.7 while idling. This looks like overcharging to me.

Would experts recomend replacing the voltage regulator, or simply buying a new alternator? Suggestions where to get quality parts would be appreciated. BTW... This alternator has only about 20,000 miles on it

Also, right at the same time my turn signal fuse blew. Replaced, and blew again. Could these problems be related?
Attached Thumbnails alternator over charging?  see pics.-alt1.jpg   alternator over charging?  see pics.-alt2.jpg  

Last edited by the171; 02-13-2013 at 08:59 AM.
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Old 02-13-2013, 11:24 AM
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What sayeth the good book? If you're really getting 15.7v idling, you're too high, and you'll fry that battery pretty soon.

I have to hesitate, though, because it's hard to get 13.2v out of a lead-acid battery (MudHippy has a chart here: You could be reading a surface charge (turn on the headlights for 30 seconds, then check again), or your meter could be reading 1/2 a volt high. But even 15.2 volts is too high for the alternator.

Over-voltage on the regulator, though, should not flash the battery light. The battery light comes on when there is continuity to ground through the test lead, which usually means NO output from the alternator. My guess is that you've got one or more things loose inside the alternator, and vibration is just tearing it up.

Is the turn signal fuse related? Hard to say, but with higher voltage the bulbs will pull more current. I doubt they are that close to blowing the fuse by design, but you could have enough corrosion in the turn signals that they were right on the edge, until the voltage went up and blew the fuse.
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Old 02-13-2013, 12:24 PM
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Thanks for the reply and useful links. Ive saved the charging information for future reference. I did take that picture of of the 13.2 directly after shutting off the truck, so that might explain that. Looking closer at my battery connections, I realized the ground wire connected from the battery to the chassis was fraying. Took it off and the bolt was all rusted inside the fender. Cleaned that, and added 2 more grounding points. Problem solved - I now have no flashing dash lights, and the multimeter reads between 14.2-14.5 while running.

The turn signal problem persists, however.

Last edited by the171; 02-13-2013 at 12:29 PM.
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Old 02-13-2013, 08:53 PM
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Originally Posted by the171 View Post
The turn signal problem persists, however.
Check all the bulbs, sometimes they short out in funny ways and cause a short to ground. Also inspect your trailer harness, tucked up in the left side, you might have one and not know it even. Th next place to look is the tail lamp relay in the drivers kick panel, inpect for charing or other shorts.

I notice in the pictures your battery has been venting, You will want to pick up a battery hygrometer/tester and a gallon of unfortified distilled water. (The two caps with white corrosion showing). Use a bright flash light and find the fill line and top up with the distilled water then use the tester bulb to verify.
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Old 02-14-2013, 04:13 PM
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I removed my trailer wiring harness, inspected all sockets and bulbs, and wiring into the sockets. Checked wiring under the box as best I could. Found nothing so I tried replacing the flasher, still nothing. Then after about 15 blown fuses I found the wire, it was hiding on me behind the front bumper. Arrrgh.... But all systems go now. Thanks guys for the input. I will take your advice and service the battery.
Attached Thumbnails alternator over charging?  see pics.-wire.jpg  

Last edited by the171; 02-14-2013 at 04:16 PM.
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