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Hey gang, I'm having a recurring dead battery issue in my '02. If I disconnect the batteries they keep a charge, and cause an arc when connected even with the doors closed for days and the hood light removed. Left connected and they're dead by morning.
Anybody know of any common issues as a place to start?
Well you're always going to get some arcing. That's just the nature of the electronics on these newer vehicles. Some juice is always used in the key off state to power ECU, radio memory, and things like power door lock receiver (if equipped).
I just went through this myself. Follow the instructions linked above. My main culprit turned out to be alternator, but that doesn't mean yours will.
Biggest culprit is usually the alternator...usually the fastest and easiest to check.
Disconnect the batteries and charge the completely.
Disconnect the alternator connection and gator clip the alternator battery feed and post through your amp meter. Be very careful with the battery feed as full potential will be there once re-connected.
Connect one or both batteries.
If not reading 0 amps the alternator is bad.
I did not read the previously linked article but see attached and it will also help insure the system is up to the task after you chase the culprit down.
My 'O2 (300k) had similar symptoms. I discovered the positive wire ran straight down from the main battery past the frame on its way to somewhere. The wire was frayed and shorting intermittently on the frame. (See first picture where the light is focused). I went to to a welding shop and got a length of equivalent wire, a connector and a new battery terminal and installed. Cut the offending wire where I could splice it (underneith motor) and soldered everything in and added extra insulation at the west point with zip ties. Problem solved.
A draw big enough to kill them overnight is probably the alternator. Easy test without an amp meter: disconnect both battery negatives for safety. Remove the nut holding the fat charging wire to the alternator, reconnect a battery negative, and touch the charge wire to the post where it's supposed to connect. Any spark indicates that the alternator is the culprit. Make sure that the charge wire doesn't touch any other metal parts while a battery is connected as you'll have a BIG spark and the possibility of damage.
If it's not the alternator, and you have an amp meter, follow the procedure about pulling fuses.
This is the method I use, after ruling out the alternator, but with one correction. There's no point in waiting for modules to 'sleep' before disconnecting the battery, that waiting time starts after connecting your meter. Our trucks don't have a "module sleep time" so that can be ignored, but many newer vehicles do.
This is the method I use, after ruling out the alternator, but with one correction. There's no point in waiting for modules to 'sleep' before disconnecting the battery, that waiting time starts after connecting your meter. Our trucks don't have a "module sleep time" so that can be ignored, but many newer vehicles do.
I was under the impression that the GEM had a sleep mode of sorts. That's the reason for the acc delay relay and why the windows still work for a short time after the key is switched.
Ok. Been dealing with it as I don't drive it much, but finally got around to tracking it down. I have a 3 amp draw on the instrument cluster fuse (10a, #35). Any suggestions?
I read somewhere about wiring in a blinker relay and using a compass to track it but I'm fuzzy on the details. Anybody know about that?
I'm so f'ing confused. I had the positives disconnected and the door latch closed to track the short. I had the wire to the fuse box disconnected from the battery cable and tested separately. 3.12 amps drops to .25 when I pull fuse #35 (instrument panel). Plug it back in and hear a click-click. Read somewhere the dome and bed light are on it too so I pulled off the bed light and unplugged it, test to find 2 amps now. ??? It wasn't on. In passing bumped door (with latch closed) into the catch and the dome light came on. Plugged in the bed light and it came on too. Checked latch again and found it not quite all the way closed, closed it and lights went off after timeout. Now get 1amp when first touching probe, drops immediately to .25 then to .1after a minute, then to zero. Repeated several times.
WTF is going on? Was I chasing a phantom because the door latch wasn't closed? If so, what's draining the batteries? They are less than 6 months old and hold a charge if disconnected.
From what I can find the #35 fuse powers the instrument cluster module which controls the interior lights. So if the door wasn't shut or the glovebox is open, maybe even the under hood light if the hood is open will draw power through that fuse.
If you don't read a draw from the batteries, then it's possible one of the batteries is the draw. Disconnect both of them from the truck and each other and take a voltage reading from each. Let them set over night of few days whatever and check them again before connecting anything. If they don't match exactly then you might have found your smoking gun.
If you're trying to do a parasitic draw test you should use a bridge. Basically a battery disconnect, the kind with the big green **** people use on cars they park for a long time. Using the bridge keeps everything connected and then you connect your amp meter across the bridge then open it. You should only read about 30 milliamp draw once everything powers down.
I had a similar issue where It would drain my batteries if it sat for the weekend and would barely start on a monday, mine turned out to be the radio. pulled radio fuse and no more problem, I have since installed a new radio.
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