On the back of my alternator there is a blue, green, ground, and the battery wire. If I disconnect the batt wire and put my multi meter on it, then put ground to the green wire will this make the alternator start to charge? With the truck running of course. When I brought the alternator to have it checked it was fine, but when I put it on I cant get it to charge. What am I missing.PLEASE HELP?

 

Check your thread in the "Help!" section.

 

the regulator is built into the ecm. there is a ground wire on the negative side of the battery that connects to the cab, remove it clean it and replace it. this is where the ecm gets its ground if it is bad the current has to travel through the drive train to try to find a path to the cab. more than one of my 93's had this problem. if this does not fix check to see if you have 14 volts on the battery lead of the alternator with the motor running. if you do there is a fuse link in that lead and is open. if that does not work there is a external regulator you can get for about $30. the last time i priced a ecm for a 93 i think it was $600 hate to see what it is now

 

The last ecm I bought was something like $220/250. It was a re-burn unit which is supposed to be like rebuilt unit. Been on there almost 2 years with no problems. Good luck with your truck. BTW the ecm I bought was from Napa.

 

With the advice from Wannadiesel I checked the crank sensor. One of the three wires was worn threw, I'm going to order a new on on Monday. Thanks again Wanna.