Q: There appears to be a short causing the battery to drain while the engine is off

asked by on

I acquired a 93 k2500 GMC suburban in June of '16. I don't know much about her history. I do know this: There had been an electrical fire in the dash; the wiring harness has since been replaced. The catalytic converter had been removed (poorly) and has since been replaced. A stereo had been installed and various parts removed leaving random wires. I have also now replaced the fuel pump and starter. The only starter that fits is a 98, so I'm assuming the transition had also been replaced. Now I think I have narrowed down the problem to electrical. I apparently have a short somewhere causing a battery drain. If I jump her she'll run, but if I don't disconnect the negative cable when I turn off the engine she won't start. I've checked all the fuses I can find, replaced the broken ones, had the battery tested, charged, jumped, and I still can't figure out what's wrong. Please help before I smash my battery through my windshield!

My car has 191000 miles.
My car has an automatic transmission.

Hi there, thank you for asking a question about your 1993 GMC K2500 Suburban. The easiest way to find the source of battery drainage is by process of elimination. Get a hold of a volt/multi-meter. Start with a fully charged battery. Connect the volt meter to the battery set to 12 volts or higher. The battery should be reading close to or a little above that.

If it’s reading lower, then start pulling fuses one at a time. Pull each fuse long enough to see if there is any voltage change on the meter. Give it 20-30 seconds at least. If there is no change, then reinstall and move to the next fuse. Do this until you pull a fuse that causes the voltage to go up. That circuit will be where you will have to start checking for a short, whether in the wiring or in an actual part.

Considering the fire and wiring repairs, I wouldn’t stop checking circuits with the first fuse removed that makes the voltage go up. Write it down and check them all. There may be more than one blown fuse. If you are not experienced with checking and handling fuses in a car, have a certified technician from YourMechanic come to your home or office to inspect and replace any fuses.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. There appears to be a short causing the battery to drain while the engine is off

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Vehicle stalled without warning at stop sign. Won't start back up. 2007 Chevrolet Trailblazer

Hi - it is possible that all of this is due to an electrical problem - a bad ground (or burned out bulb) for example will make turn signals blink fast. It could also cause a "no start" problem. But...

Q: decelerating engine while approaching highway speed.

Failure of the transmission speed sensor is a likely cause of this behavior. You have remarkably few miles for this model year! Replacing the speed sensor may be a good time to change the transmission fluid and filter as well...

Q: Was a loud tapping noise while accelerating, and then put in new alternator and got oil change, woke up this morning and want st

You need to look at the oil pressure sending unit just above the oil filter to see if it got damaged when changing the oil filter. If it is the sending unit, then replace it since the fuel pressure will...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...