Amp draw when accesories are on.

My Cherokee ammeter drops to about 12 volts when lights or other accesories are on. What do i need to do to solve this?

When does this happen ...I mean does this happen when the engine is idling, say like when your at a traffic light, or does this happen when the vehicle is at road speed (engine is running above idle)?

If this happens at idle, I wouldn't worry too much about it. I would definitely clean the battery posts and the clamps; it does not take much corrosion to create substantial resistance and this will cause a voltage drop. After you clean the posts/clamps, service the battery if the electrolyte levels are low (most batteries have water caps) with distilled water. Charge, or have the battery charged.

Mike
00XJ

Start the engine.

Is is really a problem?

My Cherokee ammeter drops to about 12 volts when lights or other accesories are on. What do i need to do to solve this?
He has not answered you guys yet...but that is a voltmeter on the dash.

Voltage is the pressure of the electricty, remember? The more things that you turn on, the more the pressure or voltage will drop. When the engine is running, the alternator will bring that voltage back up. At idle the alternator is not putting that much out and the voltage will rise if the rpms are increased. The electronics in alternator control the voltage so it does not exceed 15 volts to prevent damage to the lead-acid battery.

Now...to your original question...if the engine is on and running and it show 12 volts with all the light on at idle...I would clean the terminals and the chassis ground and see that improves the voltage. I would double check the voltage at the battery with a test voltmeter. The one on the dash may not be accurate. With all that said, 12 volts is OK....with the headlights on and the engine is just idling.