John Deere 670 Compact Tractor Alternator/Charging Issue

fratra · Jun 18, 2025

I have a JD 670 compact from 1996 I think. The battery light is on and not charging (confirmed with multi-meter), only getting 12 volts on battery while running. I've replaced the alternator twice thinking the first may have shipped bad. The second alternator the battery light went off initially and stayed off for several starts. As soon as I started backing it out the light came on and stayed on again. I did try changing the rectifier/voltage regulator and that didn't help either. Using a multi-meter I don't see any voltage coming out of the alternator connector wire either. I don't see any inline fuses I can find anyway. Any ideas??

bmaverick · Jun 18, 2025

fratra said:
I have a JD 670 compact from 1996 I think. The battery light is on and not charging (confirmed with multi-meter), only getting 12 volts on battery while running. I've replaced the alternator twice thinking the first may have shipped bad. The second alternator the battery light went off initially and stayed off for several starts. As soon as I started backing it out the light came on and stayed on again. I did try changing the rectifier/voltage regulator and that didn't help either. Using a multi-meter I don't see any voltage coming out of the alternator connector wire either. I don't see any inline fuses I can find anyway. Any ideas??

You need the TM1470 service manual to debug this issue in the troubleshooting section.
(it's for free on the YTOG)

TM1470 Technical Shop Manual 670 770 790 870 970 1070.pdf