View Full Version : Battery Light intermittent with new alternator

08-21-2014, 01:27 AM
Hello - long time stalker on this forum :popcorn:...first post! I'm running a 2002 Freightliner 140" lowtop with 400,000 miles. Still going strong! But - the other day I had a squealing noise AND battery light on dash was intermittently coming on...but not staying on. I determined the squeal to be the alternator pulley...which made sense that it would cause the light to flash on/off since it was slipping and not charging. I replaced the alternator AND belt. No more squealing, but the battery light still comes on intermittently. It stays on a few seconds, then goes off for a few seconds. There's really no rhyme or reason. The battery is new (as of January). Putting a voltmeter on the alternator shows voltage usually at 13.5v, but it does dip to 11.1 and as high as 13.9. Voltage at the battery is a constant 13.5v. The wiring harness coming off the alternator is intact. Battery terminals are tight. Hooking up the Green Diesel OBD scanner does not reveal any codes. WHAT in the world else could cause this light to flicker?!? :thinking:
Any suggestions appreciated!

08-21-2014, 02:19 AM
Possibly the new alternator has a bad voltage regulator or there is a bad connection.

08-21-2014, 02:23 AM
Check your ground cable

08-21-2014, 06:43 PM
Mendonsy was right! I took the Bosh reman alternator back to NAPA and they were pretty cool. They exchanged it and we discussed other options for what might cause the light to flicker. No one (including me) really thought the voltage regulator was bad. However, once the newly exchanged alternator was mounted up, I ha a steady 14.4v coming out of it (14.3v when hot) and NO flickering light on the dash. I called NAPA and told them that cured the problem. They were appreciative of the feedback. Thanks for the suggestions. (I did check all my grounds...they're good.)