2005 vnl670 low voltage warning

the small 3rd wire is the voltage sensing wire, which should go directly to the batteries. It controls the voltage regulator. If it is not hooked up, the alternator should still put out 13.8 volts, unless there is another problem.

 

Have you had fix the problem?
I've got same issues

 

What do you mean when you jumped power and ground directly no change?
1 the alternator is grounded directly to the engine by a separate ground wire. - correct.
The alternator is also grounded via its mounting bolts.
The sensor wire is connected and has power when key is turned on. You checked this yes?
You have unhooked the batteries from the alternator at the alternator making sure nothing touched then started the truck
You measured both volts and more important amps at the alternator and discovered that it is in range correct
Then if all are yes you have a broken wire in the harness or , or the power (amp) is going to the starter and that's where it ends.

 

Schematics for your unit attached. Refer to pages 8,9,17, and 23 for your alternator. Hope this helps.

tech349

 

Aren't Volvos Wonderful??

I wish I could own a VNX...

Yeah. Simple wire that is on the batteries directly. I think the wire is white. Actually I think there are two white wires that need to be attached. Make sure there isn't any corrosion on therm.

 

Do you have any other electrical issues? And did you check wires and contacts for corrosion?

 

Well sorry for such a late reply...... I cleaned all ground cables I could find on the truck and replaced all I thought were bad. Alternator is now charging at 13.8 volts to the batteries but the dash only goes as high as 13.2 volts down to 12.0 volts and the red battery light flickers. Not sure what to look at for now. I still dont understand the sesning wire off the alternator. It measures half of battery voltage which i was told this is normal. What is the dash using to read the voltage?

 

What is reading at the power point going into truck. Engine side and cab side. Its in the footbwell down by your left foot. Near the pedal that adjust the steering column.

 

Did you get your problem fixed. I have Dame issue now on 2015-730 Volvo. Within minutes of shutting down it goes off