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Q: Truck running very bad and I have a loss of electrical power.

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It ran no problem when I left the house, then my stereo shut off for a few seconds the it came back on, then about five miles later it bogged down and the battery light on the dash started blinking sporadically on and off. After a couple of more miles at a stop light it totally shut down. Then when the traffic light turned green it started and I made a U-turn back for the house, cylinders misfiring all the way I made it home on the back streets with a top speed of 20 mph, and with no headlights. At home, I checked the battery with a voltage meter, it read 11.09 volts. It idles fast also. I just bought the battery about 6 months ago. The truck hasn't given me any electrical problems since I had it, 2 yrs. I didn't do any work to any wiring except change plug wires 3 months ago, and changed all the exterior light bulbs and replaced some fuses over a year ago. The alternator looks old and worn, Can it be tested at an auto parts store without removing it?

I appreciate the advice.

My car has 130000 miles.
My car has an automatic transmission.

A: Hi there. Before you decide to charge or r...

Hi there. Before you decide to charge or replace the battery, check for a parasitic draw. To do this, remove the negative (-) battery cable from the battery and put a digital volt ohm meter (DVOM) on the battery cable terminal and the battery post. With the ignition switch off, see if there is a voltage of 5 volts or more showing on the meter. If there is, then go in your vehicle and turn on everything one thing at a time, which you may have to unplug switches and circuits. If something changes the voltage or if the volt meter reads 0 volts, then what ever object or switch that you operated is malfunctioning. Fix the malfunctions to the vehicle and then replace the battery. The battery is too low to recharge it and be able to hold a 75% charge of 12.4 volts. If you do not find anything wrong with any circuit with the car, then check the alternator by jumping the vehicle and seeing if there is a voltage from 13.5 to 14.7. If there is no additional voltage, then the voltage regulator in the alternator is not working and the alternator has failed. If there is a voltage increase, then check for an amperage output to the alternator. If the amperage is lower than what the alternator is specified for, then the alternator windings are burned and the alternator needs replaced. If you are unable to test the load on the alternator, then you can take the alternator to the local parts store and have them test it for you. If you need further assistance with your battery going dead, then seek out a professional, such as one from Your Mechanic, to help you.

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