I know its not a Camaro or Firebird but I can't drive one of those in the winter around here. I am looking into trading my 90 YZ 250 for a 79 CJ-7 Jeep. The problem with the Jeep is it won't keep a charge. He said that he thinks theres a short. My first thought was Voltage Reg, Alternator, or battery. How would I track down the problem. Thanks in advance for any and all advice. Cant wait to get a few replies. Latter

 

An easy check for the alternator (dont do this on a thirdgen), is while the engine is running, disconnect the negative battery cable. If the engine stops...the alternator is bad.

 

Why can't you do this on a thirdgen?

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92 Bird 3.1L Auto
Best $750 I ever spent....

DRIVE IT LIKE YOU STOLE IT!

Kills:
93 Mustang LX (Before Mods)
98 or 99 Dodge Stratus (tough one, edged out at 40)
92 Camaro RS 305 TPI


Close Calls
94 Grand Am 3.1 V6
92 Cavalier 3.1 V6
01 Porsche 911 Turbo (Had em till first gear)

Mods-Jet Stage 2 Performance Chip, Accel Cap/Rotor, Accel 8.8 MM Wires, Accell Coil, AC Delco Rapidfire Plugs, Dynomax Catback, K&N

AIM name OVRCLCK350

 

Another thing to consider when a battery supposedly "won't hold a charge" is that something in the vehicle might remain on after the key is off & slowly discharge your battery.

Try this: Buy an Ammeter (they're cheap) and hook it between the Positive battery terminal and the positive cable. See if any current is flowing. If there is, then remove your fuses one at a time until the current flow stops. When it stops flowing, you will know that the fuse you just pulled controls the circuit where the problem is.

This will eliminate a lot of guesswork quickly.

 

To make a rough check of the alternator:

Hook up a voltmeter to the battery and record the voltage; it might be around 12.6 volts. Now start the engine and check again. The voltage should be higher, like maybe 13.8 or so. (This still doesn't mean your alternator is perfect, but at least it's working.)

Get the battery load-tested. It's free at most big-chain auto parts stores, or Sears or Firestone.

As long as you have a good alternator and battery, then something in the car is staying "on" and draining the battery. Like Don says, do the ammeter and fuse thing.

Of course, this is a Jeep so it probably doesn't have a lot of fancy options. That should make the problem much easier to solve.

Is there an underhood light? Maybe it's not going out when the hood is closed.

Does it have an alarm? Try disconnecting power to the alarm and see if that helps.

Check out the installation quality of the radio. Maybe temporarily disconnect that too.