Battery or Alternator?

November 15, 2009, 11:13:38 pm

I have yet another problem with my 06' Seneca. Sorry for the long post!
Went on a 60 mi trip to the state park this weekend and upon arrival and backing into my spot the battery light came on on my dash. Parked for the weekend and went to leave without the battery light on. Drove most of the way home and pulled over for fuel and on the exit ramp the battery light comes back on followed by the brake light and the ABS light. Pulling up to the pump and all of my dash gauges went to zero except for MPH and RPM. No choice but to drive home with intermittent flashing of ABS and Brake lights and full time battery light on and no gauges.
I parked the Seneca at home and plugged in for two hours while I watched the Saints win #9. Opened the battery bay under the passenger cab step and see no visible corrosion but pulled each wire and cleaned, finding one with some corrosion under the rubber terminal cover. Disconnected from shore power, I cleaned an replaced all wires, started the engine up, and found all above warning lights off and gauges functioning. Drove the MH to the storage lot without incident.
Was the fact that I was parked and plugged into shore power while camping indicate that my batteries are good and accepting a charge from my inverter only to die in transit due to a bad alternator? Or does it mean that my batteries (Gel) are going bad and can't hold a charge so I drove home on just the alternator?
I would like to diagnose myself as I just spent $125 last week to clear a check engine light that the dealer said was for a previous issue that I cleared a month prior by changing the fuel filter (no check engine light for the last month). Yes., I paid $125 to find out that I fixed the problem myself.
A buddy had a tester that he put in the cig lighter of the MH and said he thinks the corrosion was the problem as since I cleaned the terminals the tester shows good power from the alternator and the batteries.

Re: Battery or Alternator?

Reply #1 – November 16, 2009, 05:01:28 am

Yahoo Message Number: 3289

The battery connection may have been your problem. Another area is grounds on the frame and engine.
Plugging into shore power will not charge the batteries under passenger side step unless you have an external charger for them.

The GM owners manual has this description for the light.
The charging system light may be located in the instrument panel cluster, or with the auxiliary warning lights in the center of the instrument panel.

It should come on briefly when you turn on the ignition, before the engine is running, as a check to show that it is working.

If it stays on, or comes on while you are driving, have your vehicle checked right away. You could have a loose generator drive belt or some other problem.

Driving while this light is on will drain your battery. If you must drive a short distance with the light on, turn off your radio and other accessories. Sustained driving with a generator failure could result in a lack of back-up braking if the engine quits or the power steering pump should fail.