Prostar Alternator wire?

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by artycbear, Feb 21, 2020.

  1. artycbear

    artycbear Bobtail Member

    Feb 14, 2020
    On a 2009 Prostar Premium, I have replaced the Delco Remy alternator with a Bosch. The D/R had one hot wire, a ground wire and a third wire attached to the post marked Sensor. There were 2 more posts on the D/R alternator labeled R and I, which were unused. The new Bosch alternator has post for 2 Hot battery leads (i used one) a Ground wire bolt, and two other posts, one for the tach gauge and one for the alternator light. I have no idea which of these two posts to run my third wire to. I left it unattached (the third mystery wire) to see what wasn't working without wire hooked up. The tachometer worked as well as the voltage gauge, so i'm not sure which post to put the third wire on. Any help would be appreciated, thank you.
  2. pushbroom

    pushbroom Road Train Member

    Sep 1, 2012
    Medium & Heavy Duty Alternators | Delco Remy

    That probably has the best explanation on the remote sense wire. Quick and dirty is the remote sense wire gives the alt a voltage read off the batteries without having voltage drop from dirty battery cables.
    If the new alt doesn't have a spot for it just heatshrink up the terminal so it cant spark out on something as it will be hot (+12V). More ideally would be to remove the wire completely, no idea if its factory or added on after the fact.
  3. Heavyd

    Heavyd Road Train Member

    Feb 4, 2009
    Yes. Just what Pushbroom said. It's the remote sense wire. Cover it up and tie it away. Ok to run without. It will be factory and should be a 5 amp fuse for it at the batteries if you want to disconnect it.
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