89 GMC Cummins conversion

[COS399]

So, I spent this weekend trying to figure out why my alternator wasn't charging my batteries. To make a long story short the problem was with the wire that originally came with the truck, and that I had marked as being the alternator wire before removing the original engine, was only putting out 3 volts to the alternator. After jumping from the battery straight to the field wire it started charging like it should.

The internal Voltage regulator that I picked up at Ken's was not intended to go into this style of alternator but could probably be made to work. Since I had a bearing going out in it any way I decided to order me up a 1st generator (120 amp) alternator to put in it. Of course the price difference between the two also made the decision easier. I am attaching pictures of the internal VR going into the 1st gen. alternator.