The never ending SAIS diagnostic or...

Mark20

Original poster
Member
Dec 6, 2011
1,630
Is my alternator dying or do I have a bad ground or...

On my trip up to NYC/LI the other night I noticed the headlights dim. At first I thought it was the SAIS diagnostic that fools so many. But the headlights kept dimming, dash volt meter dropped and the Scan Gauge showed varying voltages (12.6 - 15.6 V) when the RPMs were less than 1800. If I kept the RPMs up, everything was normal. After I parked at the hotel I hit the brights at idle hoping to see flickering/pulsing but they were solid and the Scan Gauge only dropped from 14.4 V to 14.2 V. This all happened Sunday night, everything was fine Monday and Tuesday.

I haven't had a chance to pop the hood and check the obvious connections on the alternator and battery. Searching here indicates it could be a bad ground connection.

Can I assume this is the alternator heading off to retirement (just under 100K miles) or will I need to dig deeper? I should have some time today to check the main connections.
 

BlazingTrails

Member
Apr 27, 2014
19,409
Mark20 said:
Is my alternator dying or do I have a bad ground or...

On my trip up to NYC/LI the other night I noticed the headlights dim. At first I thought it was the SAIS diagnostic that fools so many. But the headlights kept dimming, dash volt meter dropped and the Scan Gauge showed varying voltages (12.6 - 15.6 V) when the RPMs were less than 1800. If I kept the RPMs up, everything was normal. After I parked at the hotel I hit the brights at idle hoping to see flickering/pulsing but they were solid and the Scan Gauge only dropped from 14.4 V to 14.2 V. This all happened Sunday night, everything was fine Monday and Tuesday.

I haven't had a chance to pop the hood and check the obvious connections on the alternator and battery. Searching here indicates it could be a bad ground connection.

Can I assume this is the alternator heading off to retirement (just under 100K miles) or will I need to dig deeper? I should have some time today to check the main connections.
It sounds as though your alternator is on it's way out. It is always a good idea to check the connections, especially to the battery that often get bypassed. get a memory saver though before you unhook it to clean the connections.
 
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