Rich and I were working on an alternator issue today that I've never run into. I know how to look for the usual stuff, but this one has me stumped. Start car - alternator light stays on, charging system at 12.1 volts (DVM, not the dash gauge. Dash gauge looks to be about 9 volts). Rev Engine - charging system jumps to 13.9 volts, light stays on. Let it idle back down, stays at 13.9, light stays on. (Dash just above the 13). Things we tried - remove light bulb - acts exactly the same (but with no light - duh). Checked wire (brown w/yellow trace) from alternator to idiot light with both ends disconnected - no shorts to ground, overall resistance of the wire less than an ohm. Cleaned up bulkhead- to-frame ground, bypassed engine-to-frame ground, check all connections at instrument cluster. Checked connections at alternator (all those stupid brown wires). Tried another battery. Keep in mind that the car starts and runs fine, which rules out most of the grounding issues since the starter ground and alternator ground are essentially the same path. I'm suspecting that the regulator in the alternator is bad, but we tried three different used OEM Motorola alternators (all of admittedly suspect quality). Unfortunately I'm not sure the other two worked the same - we didn't try reving the engine with those. In all the cases the idiot light was on brightly. Next step is to replace the alternator with a new one, but did I miss anything? Dave S To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/