320B Electrical problem

[Big Iron]

320 B 8900 hrs 5BR SN
while operating yesterday the Battery/Charging fault light pops on. I checked the voltage at the Batteries motor off 25.6V
started the engine at idle 27.9 to 28V. all the electrical stuff works (heater, radio all computer functions, ect) all connections look good and are tight
how do I pull up the computer codes on this machine? any ideas as to what could cause this
thanks

 

[Per Eriksson]

"P" terminal on alternator is supposed to have a connection with the ecm, most likely you have a broken connection or wire on that circuit.
Or a bad alternator.
It's the green wire on the alternator, with that disconnected and engine running the terminal on the alternator should have around 15volts.
On the ecm it's pin 34.

 

[Big Iron]

thanks Ill take a look

 

[Big Iron]

well I pulled the grn wire on the alternator, with the engine running there is 13.9v there. cleaned the terminal and reinstalled the wire. bat light still on. still getting 27.9v at the batteries running and 25.6 off. probably going to pull the alt and take it in and get it checked just to make sure. need to get a wiring diagram for that machine.

 

[Per Eriksson]

Did you check it at the ecm also?

 

[Big Iron]

No to lazy today to get in there that would be the computer under the seat correct

 

[Per Eriksson]

yup

 

[Big Iron]

thanks soon as i get these brush piles burned tomorrow ill take it to the shop and trace that wire. i think your right though, cause the batteries are charging just fine and everything works great except that darn fault lite.