Hey all I have kept my 6.0 excursion out of the hands of the 75 dollar an hour guys by using this site so thanks for all of that but... a new gremlin is haunting my excursion. I have a 2005 Excursion and the charging system works one day and not the next. I have Installed new batteries which load test fine. I have 12 volts on the red wire side of the 3 prong 2 wire plug key on or off and the green side key off its almost a ground, key on and it has 11.75 volts. I have traced out the wires to ensure they are not broken or shorting out some where and they are not. When the system is working it only puts out 13.4 to 13.8 volts. This is the same with two new altenators. The parts guy said there was nothing wrong with the old altenator. What else is there? Any ideas or obvious solutions that I have missed. This is the wifes truck and she is being less than patient about it.

 

When you say it's working one day and not the next. What is happening to tell you it's not working?