2005 freightliner columbia with low voltage reading

Where is that? In the box?

 

It's the cable that connects your batteries to each other. I changed both positive and negative.

 

Thanks a mill. That’s the next thing I’ll do and check the difference. My voltage went up to idling at 14.2-3 when I cleaned mine off but it still has a tendency to drop when I’m rolling.

 

Have a freightliner doing the same thing now when I out the high beam on the dash board lights up and the guages spin round. Like they do when you first turn the key on. And the workshop can't find any thing wrong