when i park my 2000 grande cherokee over night my battrey goes dead ?
3 Answers
There can be a number of causes for this but the most common is an interior light left on. The next, and a little more expensive to fix is a bad diode in the alternator. This can be checked with an ammeter for parasitic current draw when everything is shut down. Two or three tenths of one amp is normal. Anything higher than 1 amp is definately suspect. Take your Jeep to an Advance Auto Parts store and have them run a full charging system test on it. They do it for free but be sure to tell the guy testing it to perform the current draw test which is the last of 4 tests their maching can do. There will also be a graph on the results strip that shows alternator "Ripple". Excessive ripple is an indication of bad diodes not converting AC current to DC. A diode only allows current to flow in one direction. A bad one will allow flow in either polarity which allows current to draw down to ground when everything is shut down, draining the battery in the process. Hope this helps!
Check the battery. Put a volt meter on it when the car is running to see if it is getting a charge from the alternator. Also if the battery is more than 2 years old it could be defective. Another problem is that the hood or glove box light is not shutting off when closed. When left parked long enough on a weak battery, it could be enough to drain it. Either do it yourself or just take it to a shop and they can run a testing meter on the alternator and battery for problem spec voltage and amperage levels.
