TheHummerguy said:
Which one? what should my output voltage be for each unit?
I only have the right alternator since I went to a straight 12 volt system. I try to keep these alternators between 13.8 and 14 volts. Mine was pushing 15.1, so I pulled it apart and put a new regulator in it.
If you can load test your electrical system, you can check the output at each alternator. Testers for the 24 volt systems are few and far between. Another way would be to remove the alternators and run them down to the parts store to be tested. They will usually test them for free.
Most of the parts stores have a hard time getting replacement alternators for these trucks (even when we supply the part numbers.) They can be rebuilt easily if you locate the parts. I replaced the following parts in the spare alternator (1105500) I built:
Rectifier - D10
Diode trio - D6
Voltage Regulator - VR-111
Smitty
These are all Standard part numbers.