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Alternator going bad?

Discussion in 'Ford Trucks' started by blee1ash, Jan 19, 2011.

  1. blee1ash

    blee1ash Senior Member
    Messages: 107

    I have a '97 F-250, with the 460 with 100,000mi. I have plowed with this truck for 3yrs, with no problems untill now.
    When I raise or angle the plow it puts enough electrical drain on the truck to make the engine miss. It has not done this in the past. The battery was new last year and as far as I know it is still good. As soon as I stop moving the plow the electrical system recovers quickly, and it runs fine.
    I believe it is still the original alternator, don't know what output. All connections are clean and tight on the battery and plow. Do you think the alternator is just getting weak, or do you think there is another problem?

    Do you know of a way to test how many amps the alt. is putting out, the voltage is fine?

    If I upgrade to a high output alternater, how big do you think I need?

    Thanks for your help.
  2. Trilogy

    Trilogy Junior Member
    Messages: 20

    Most parts stores and mechanics have tools to check the amps. Could be a voltage regulator.
  3. redplowman

    redplowman Member
    Messages: 61

    Don't rule out the battery just because its newer. Ijust replaced two one year old batteries that were bad. I wemnt to gel batteries. Have charging system tested to be sure.
  4. geer hed

    geer hed Senior Member
    Messages: 275

    If you check with your local auto parts store, they can usually tell you what the output is on the stock alt. Some auto stores will even test the alt. for you. The only thing you need to test one is a load tester. with the engine off it should read about 12 amps, then when you start the engine it should read about 14 amps. Your local Ford dealer or any repair shop should have a tester for doing this. But even though the battery is only one year old have them unhook the battery and load test it by itself, I have seen MANY MANY times where a bad alt will wipe out a battery, and vise versa. also you can check in your area for a shop that only does altenators and starters, since the volt reg is built in to the alts. nowadays a shop like that can test the voltage regulator also to see if that is the problem, not that it matters you still have to replace the whole thing. Your local stores or dealer can tell you if you can get a higher output to fit your truck also. If you have added any other extras like lights, higher power sterio, amps that kind of stuff you may want to go up as high as a 200 amp alt. Just remeber the higher the amp the higher the price.
  5. blee1ash

    blee1ash Senior Member
    Messages: 107

    Thanks. I'm going to have the alt and battery tested today.
  6. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    How old is the pump motor? It could be drawing a bunch more amps then normal. Check it's connections too. It needs a good ground too. As always protect the connections with Dielectric grease. Use the the search function on the gray line above. Search: Low power, Charging, Duel batteries, Lights dim --> There will be days of reading there.
  7. tjctransport

    tjctransport PlowSite.com Addict
    Messages: 1,390

    have your plow motor tested. if it is drawing over 175 amps, it is near the end of it's life.
    the lower the current draw on the plow motor, the more happy your truck is going to be.
    your truck should have a 95 amp alternator in it. you can get a 130 amp to bolt in, or have a shop built you a 200 amp alternator in the 130 amp case.
  8. blee1ash

    blee1ash Senior Member
    Messages: 107

    I had the battery and alt. tested. Both tested fine. I cleaned all terminals on the battery and plow, seems to help some but haven't had a chance to use it much so I'll see what happes with the next snow. I will be testing the amp draw from the pump motor.