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new alternator problems continue 850

Just installed new alternator (from FCP) in my '97 850 T5. Initially everything worked fine, but after running for ~10 minutes turning off then on, all of the lights on the dash are on. Any ideas - I love my 850 but it is costing me a fortune.

Thanks








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    I think it's time to go back to basics. First, take the battery to a parts store and have them load test it-- it's the best way to know for sure whether it is good-- voltage doesn't give you enough information. Clean the battery posts and make sure it is fully charged.

    Move on to the cables. If the negative terminal was bad enough to replace, the whole cable may have corrosion inside. It is worth measuring voltage drops on the cables (a new alternator won't work right if the cables are acting as resistive elements and producing heat). Unbolt and clean all the connection points. Measure the voltage drop on the B+ cable to the fuse box too while you are at it. Sometimes bad cables get hot to the touch when the car is running-- my positive cable was so hot it was hard to touch when it went bad.

    With a good battery and proper cabling in place, start the car and measure the alternator output at the big terminal on the back. You want to see 13.7-14.1 VDC (output is temperature and load-dependent). As Klaus mentioned, check the small exciter wire and its connection where it connects to the alternator.

    Make sure your serpentine drive belt is in good shape and not slipping. Also, make sure that the alternator light on the dash comes on in key position II-- it's part of the charge circuit.

    These problems are frustrating, but the system is relatively simple to diagnose if you are methodical and take measurements at each point. Post back with numbers and people will help.

    Good luck!



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      I went through this same drill, had a used known alternator to replace and it worked for about ten minutes, alternator light was barely visible but it was on and eventually all the dash lights came on. The alternator was very hot and there was a little smoke visible.

      I replaced the electrical portion of the ignition switch and a new alternator,problem solved. I did find that if I moved the ignition switch a little the dash light s would go out but essentially the alternator was already fried.

      I was able to get the switch from Rock Auto dirt cheap as they just had a few left and it was an OEM part.

      At 360k the car is still running like a top. 1995 850 wagon



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    You have to have a simple volt meter for these sort of problems......when you touch the leads to the battery with the car running it should be like 14.1V or something close. If not, you have a bad battery, or any number of other problems. At least you know it's not the alternator.

    Keeping it running is expensive as hell and you need to keep a triple A card in your wallet, a pair of walking shoes in the glove box along with a platinum visa card and know a good taxi service.



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    Check the wiring on the alternator, the small wires too. After starting the engine, try jiggling the key a little bit if all the lights are on. I am assuming the alternator turns easily with the engine running.
    --
    Keeping it running is better than buying new



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      The battery is being recharged. I'l try jiggling the keys after the recharge.

      Thanks



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        Jiggle did not work. Dash light still on. Other symptoms:
        1 - condenser fan stays on after car is shut off
        2- negative cable clamp cracked (new just installed last week - I guess it was over tightened)
        3- Battery voltage dropped from 12.11 to 10.8 after driving for about 5 mins.now car will not start. Maybe bad battery?



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          https://www.youtube.com/watch?v=LGB6ZEjGm7Q

          So your battery was not fully charged when you started the car. But the dash lights are on because the alternator is no longer putting out voltage. It could be a belt slipping (check tensioner) or a failed cable.

          The battery cables must be 'snug', not gorilla tightened. Check that both red wires are connected.

          Remember, if the alternator is not charging the battery, ALL electrical use by running the engine is coming from the battery. Your battery is just fine.
          --
          Keeping it running is better than buying new



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