Hi Everyone, my daughter's '92 240 stopped charging recently - the alternator was tested at an automotive store and they said it passed. I'm only registering battery voltage at the battery posts, and alternator B+ post to ground.

Initially I thought the issue was with the exciter circuit as the dash light for the battery wasn't lighting. I pulled the cluster and swapped the battery light with a known good light and no difference. At that point I did confirm continuity from the red wire at the connector on the back of the instrument cluster through to the exciter spade terminal on the alternator. I do see voltage at that spade connector when key is on.

I am now thinking it's a bad ground wire. Would the easiest way to test measuring voltage from B+ terminal to alternator body? If I get no reading then it's a bad ground, correct?