Combines 1688 not charging

Check your batteries. My 91 1680 was not charging at wheat harvest replaced alternator. Worked fine until fall. Got it out of shed and then it wouldn't start after a couple of days. Hook the charger up and it would fire right off. Checked batteries and had one that wasn't showing 12 volts. It had some kind of internal short. Replaced it and solved the problem.

The alternator should not have to be excited. I have found that if the cable from the batteries to the starter are green, or corroded about three inches back from the end, this could cause a charging problem. Check negative ground cables, especially where it grounds to the engine block. The best way to see if it's charging would be to use a volt meter on the batteries. Hope this helps. If there are any other indicators to your charging problem, write back. Will try to help.