The battery light comes on intermittently then.

OBIRON54

MEMBER
2003 MAZDA 6
145,000 MILES

The battery light comes on intermittently then goes back off. The engine light does not come on. It is difficult to test when the light is on because it does not stay on for long periods. I checked the battery and alternator. The only problem I could find is that the battery cable ends were not very tight on the battery posts they were as tight as you could get them with the adjusting nut, so I replaced both of them. It is still happening. It is difficult to get directly to the alternator. The measurments look OK at the battery. The only other issue I could see was that some of the cable anchors for the wires coming from the alternator were broken and one of the plug wires had a questionable area on it where it hd been laying against the manifold. I used zip ties to anchor the wiring and plug wire. It still didn't appear to resolve hte issue with the indicator. Any suggestions?

3 Replies

KHLOW2008

MECHANIC
41,815 POSTS

This could be a sign of the alternator about to go out soon as the carbon brushes could be running short and not providing proper contact at all times. When problem occurs, try tapping the alternator and if the light goes off it could be it.

The other possibility is a failing alternator rectifier within the alternator or the wires that you mentioned that are damaged. Check for wires that could be almost broken and not making the required connections. Wiggle the wires at alternator and check if the light comes on.