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Discussion in 'Ford Trucks' started by Hometown Landscaping, Feb 28, 2001.

  1. Hometown Landscaping

    Hometown Landscaping Junior Member
    Messages: 28

    the alternator on my 89 f-250 doesn't seem to be powerful enough, when i slow down and stop at a light my lights and fan dim, to make up for this i turned my idle up, i can tell it is costing me. the funny thing is when the fan or lights are on seperate at a stop light there is no problem it is just when they are used together? is getting a bigger alternator the only way to solve this problem, maybe the alternator is not the problem.
  2. cat320

    cat320 2000 Club Member
    Messages: 2,224

    when I was plowing with a f350 with a continetal plow hook up from dyer sales in N Reading,ma it would work fine for awhile but after useing it alot and with all the other stuff on lights 2ways radio strobes and angleing the plow all the light would blink and go dim then the truck accully shut off. had to push it into the garage and be put on the charger. You might want to be adding a bigger one if your drawing that much power.
  3. matthew Urban

    matthew Urban Senior Member
    Messages: 129

    my 92 F150 was doing the same thing. first i thought it was the fog lights i have on it, but after asking a friend turned out the regulator was dying.
    A new alternater was all I did, as its built in on my truck.
    I'd test the charging system and se what you find.
    good luck
  4. 75

    75 PlowSite.com Addict
    Messages: 1,382

    Definitely go through and check out the complete charging system, right from the battery. Your alternator should have no trouble keeping up with electrical requirements - assuming of course you're not doing a lot of plowing or winching, in which case an upgrade to a stronger charging system may be required.
  5. wyldman

    wyldman Member
    Messages: 3,265

    Rob is right,go through and check every thing.A weak battery may also cause the problem.Wouldn't hurt to check the amperage draw on the blower motor and blower motor resistor for excessive draw.Another thing to look at is the blower switch.Usually they get pretty burnt up,which only add's to the amount of current draw.The switch burns up due to a bad blower motor or resistor.

    JD PLOWER PlowSite.com Veteran
    Messages: 751

    psd alternators.

    This is kinda off topic, but I was told that the newer diesel's have dual amp alternators and the computer will not take anything larger than a stock alternator. Has any one heard of this before? If anyone knows of a way around this I would be grateful for any info you have. The reason I bring this up is my plow seems to be killing my blower fan and lights when I raise the plow at the end of the run. Thanks JD.
  7. wyldman

    wyldman Member
    Messages: 3,265

    I don't believe the newer Ford alternators are tied into the computer at all.Even if they are,like a chrysler,it should be no problems upgrading to a larger one.They do have dual alts as an option.I would take a look at your batteries,as being a 97,they may be on there way out.Most diesels go thru batteries every 3-4 years.
  8. oldmankent

    oldmankent PlowSite.com Addict
    Messages: 1,322

    JD, looks like your post at ford-diesel got some good replies. Just what you need?
  9. Winterworks

    Winterworks PlowSite.com Veteran
    Messages: 97

    That is a common problem for that era of Fords. The stock alternator is only a 75 or 80amp which is too small for a work truck. An auto electric shop can boost its output up near 130amp tops due to the case size etc. Other options are a police alternator however you need new bracketry. Your cheapest option is having yours rebuilt to put out 130amps and installing a new battery with 1000 CCA or higher. You should not have a problem then. The alternator may not charge at that high rate at idle however. Good luck, Pat
  10. 99SDPSD

    99SDPSD Senior Member
    Messages: 118

    Dual alternator are na option on the ford super duty power stroke diesel's. They come standard with a 130 amp alternator.

    from NJ
    Messages: 196

    I had to put a larger alternator into my F250 super Duty and it's a 200 amp set up now.. And this hi amp set up does not charge hi at idle, so everything dims alittle. But this is the way it works with the hi output alternators, just the way they are designed so they do not over charge the system when idleing.
  12. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    Hot rodded alternators do not charge good at low RPM's because they do not have enough surface area inside ,so they need to be spun fast,to generate the high output,when at low speeds they are no better than the 60-or 70 amp alternator they were rewound from.They will not overcharge at low rpm's,in fact they are usually at full field and cant keep up,thats why the lights dim,its working at its max.