Battery Draining on 99 Durango 5.2l SLT

It is very possible you have a bad battery cable or connection on either end. Often corrosion creeps down under the insulation eroding the cable. Since its under the insulation its not easy to detect.

Heres a simple quick test you can do. Take a volt meter and measure the battery voltage. Now start the engine and measure again. Should be a bit higher, typically 14v with engine running. Next, turn the headlights on and measure again. If the alternator is working the voltage should not drop when the headlights are turned on. If the alternator is not charging then the voltage will drop some.

It's also quite possible your new batter is also bad. It happens.

Jas> I'm stumped...

You need to be a little more clear on how the new battery died. You did give a mileage but in relation to what? Did you put it in and drive right away and it died or did you put it in and drove that far and the next day it was dead or did you put it in and a few days later took that drive and it died after 100Km? You did mention a wiring problem due to corrosion and you could have a similar one on the charging side. Do you have a volt meter? If not I would suggest you get one as the low cost one are quite cheap anymore. If you have one, check for voltage (with the battery connected) on the alternator output terminal (engine not running). You should be getting battery voltage here and if not, then you have a failed cable or blown fusible link. If you have voltage here, start the truck and measure it again. It should now be higher, around 14.5 volts and if so, measure the voltage at the battery. It should be the same at the battery or within

1/10th of a volt difference. If it is lower than that, you have a corroded connection from the alternator to the battery. If the voltage on the alternator output is still at battery voltage (12V) with the engine running, your alternator is not charging which could be a problem in the regulation side like a bad field wire or a computer failure. As a final test if everything else checks out is to put a load on the system (headlights on) and check the voltages at those two points again. If the voltage is now different between these two points then again, you have a corroded connection between the alt and the battery. If everything checks out ok, it looks like you might have something that is now constantly drawing current. Post back your results form your checks and we can go forward from there.

Sucks when people don't give you all the information, doesn't it? :)

Well, when you're grasping at straws and don't know what information to give in the first place, what can you do? ;-) Thanks for the insightful comment though...

Put the new battery in, did a day of normal driving around town, thought all was swell, then the next day noticed (based on reading the dash gauge) that it appeared to be draining. Coming home last night it was near 8V and the 'check gauge' light was on. I parked it in the garage overnight and checked it in the morning by starting it, it immediately went up to 14V (again, by the gauge - I don't have, but will purchase tomorrow, a volt reader). I drove it today (had to get the wife to work), and everything seemed fine - it wasn't draining. I then turned the lights on, and noticed an appreciable difference immediately - the gauge dipped to about 11-12V. I turned the lights off and it stopped. I also had the radio and heater off.

The corrosion was right beside where the battery is housed - so you're probably right. I'll look again tomorrow.

I appreciate the help very much! I'll get the voltmetre tomorrow and report back how I did!

Jason

When you indicate that the rig charging or discharging do you mean the battery is totall dead and won't run the vehicle, or are you watching the voltage being measured by the in-dash voltmeter changing from 13+ volts to something less than 12 volts?? If your serpentine belt is original or has any visible cracks on the ribbed side of the belt, it likely is reaching the end of its useful life and should be replaced. There is no actual "adjustmet" for it however with this vehicle it is advisable to also replace the spring tensioner at the same time. Any belt squealing heard is also a telltale sign. My '99 would squeal when cold sometimes and on occaision when turning the steering close to its limit when cold. Put on a new gates belt and a new tensioiner and it has been fine since (approx 25k miles ago). Does the battery retain a charge any better if you disconnect the negative lead when you are not using the rig? If you haven't tried it, might provide additional insight. Also, if there is something continuiously "draining" juice from the battery regardless if you are driving it or not, with the battery disconnected try measuring the "resistance" in ohms between the two disconnected leads in the vehicle using your trusty "volt"meter which is usually referring to a "multimeter" Radio shack or harbor freight have meters that will do the job for less than

15$, sometimes less than 5$ on sale. If something is "loading" the battery you will read a fairly low resistance on the "ohms" scale of your meter. If it is normal, you should read almost nothing, an "open circuit" with no way to draw amps from the battery. Some things to checck out anyway. good luck, regards, Joe.