2nd Gen Non-Engine/Transmission Battery running down any ideas on likely shorts or parasitic draws when parked?

[JStankus]

The batteries in my Dad's 1998 2500 has been losing charge while parked. He has replaced the batteries and the alternator. Any thoughts on where shorts may be likely or other parasitic draws. He drives it only occasionally since he retired, so it can sit for a while, but only started having this problem recently.

Any ideas?

John

 

[DanielCrawford]

Mine has been loosing the charge also. What I found was the radar detector was plugged in. the clock on the radio drains the batteries too. My back up cam plugged in. On top a weak batteries don't help either.

 

[fest3er]

Other than the standard low current draws, here are some 'failure' draws.

• Power seat harness can short against the seat frame. The autoresetting fuse in the dash power panel will be hot enough to blister skin if this happens (but before the batteries drain); check after driving a while.
• Power seat switch can be 'gummy' and stick in one position or another. See fuse comment above. This and the previous may not result in drained batteries.
• Alternator could have a bad diode, allowing current to 'backflow'. This should result in overnight battery drainage. But you replaced the alternator.
• One or both intake heater relays can stick 'on'. But this likely results in melted stuff on the manifold. And results in rapidly drained batteries. One indicator is all lights (outside and dash) flicker irregularly on rough-ish roads, but don't on smooth roads.

Took years before I discovered why my lumbar switch didn't work (not that I looked all that thoroughly until one of the up/down switches also stopped working). And why that fuse would overheat. Had to take the seat cushion off *and* had to notice the tiny bit of arc residue on the frame *and* then find the holes in wires' insulation.

 

[Joseph Donnelly]

Disconnect one battery, then take one cable off the other, and bridge with a meter to see how much current is being drawn. Then, one by one, remove each fuse until the draw is gone.

 

[JStankus]

My dad found the problem. Switch mount for glove box light broke leaving the glove box light on continuously.

John

 

[MLee]

My dad found the problem. Switch mount for glove box light broke leaving the glove box light on continuously.

John

Thats always the culprit, 9 times out of 10. That was going to be my suggestion.

 

[JLEONARD]

I had my under hood light stay on and drain a battery.

 

[AllianceDiesel]

If you have a test light, disconnect both negatives from the batteries. Hook the test light between the neg clamp and neg post. The test light will be super bright if you have a major draw but will always light up because of ignition off draw. Now start pulling fuses like said above. I have seen one battery bad that would draw the other battery down.