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Alternator light question
Yellow warning light would come on after driving say 15 miles. It did this a couple of times. Checked volts at battery with and without motor running and lights on. Everything checked out well. Replaced warn alternator belt. Made sure the new belt had correct tension. Starting the car now the warning light comes on immediately. Replaced voltage regulator, ran another ground wire to alternator, checked each wire and connector, replaced battery cable ends, had alternator triple checked. And still the warning/idiot light comes on and stays on after starting the engine. Car starts first time every time. I checked with Blas and we came up with a solution. Put a piece of black electrical tape over the light! Any ideas what could be causing this? Thinking about running new wiring from voltage reg to alternator to see if this could solve the light issue. Thanks!
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Is the voltage regulator case grounded?
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The VR case is grounded 2-3 ways. In your opinion, what is the best way to ground? It might be a way I haven't grounded it yet. Thanks for the reply
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Either with a wire from the mounting screws to ground or the volatage regulator mounted with screws into the grounded frame.
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From our phone conversation, it appeared you had check or replaced everything in the charging system. Verified wiring connections, grounds, battery condition, alternator output voltage, etc. You also stated that you are not having any starting problems...But the charging light persisted...
I may not as familar with your manufacturers wiring design, but they all work similar. Sometimes waiting for something to outright fail is the easiest thing to do...at worst you'll need a jump to get the car home...and the problem will then be evident. Did you have the battery load tested off the car? The black tape comment I made was an attempt at humor...(you could also remove the bulb from the indicator light for a cleaner look on the dashboard) |
Take to a generator tester place and have it loaded to test
psycolSEAL I don't trust Autozone or pepboys for testing but both have tester for Alt. It sound like one of the bridges or diodes is going bad. If everything is checking out, what is the voltage at the battery at idle and 1,500 rpms. We want to see about 13.8-14-2 voltage. without any loads. Then repete the same thing with headlights, fans, fuel pump, blower motor all on high speed. Tell us the voltage readings again at idle and 1,500 rpms. Test for 10-15 seconds. Do this with the motor cold and at operating temps after 10-15 minutes of the car running with hood closed. Tell us what the tests come out to. Do you know a Jim Watson?? believe he's a master chief?? Try the test. Rick L.
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Blas, I know you were joking. I shared the tape remedy with a few friends, they got a good laugh out of it. I appreciate your help!
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Rick and WBulk, I will check again on Sunday. I appreciate your input. Things like this drive me up the wall!
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Battery engine off 12.5
At 1200 - 1500 rpm 14.3 Engine warmed up with fan on 13.9 Ran another ground wire to a different location on block. Light did not come on until running for about 1 mile. Light came on and then off after a few seconds. Drove approx 3 miles with no alternator light on. Checked voltage at altternator when running. Same reading 13.9 with fan on. ??????????? |
Quote:
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13.9 at 1200 - 1500 rpm Taurus 3.8L Low speed fan
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Note:
A battery at a 12.45V charge (resting) is holding only 75% charged condition. * If you have the means, swap batteries and see if the light persists...Could be a bad cell. I have a deep cycle battery on my desk that shows 12.68v charge but the charger always showes it need a charge...Bad cell or sulfided battery. |
Took the car out again for a longer drive tonight. No warning light. I'll do the same thing tomorrow. If all else fails, I'll replace the alternator. It is an Optima red top battery.
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Ran the car for a good 20 minutes. NO alternator warning light seen! For now!!
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