Grounding and power drain

[BlizzardVan]

Has anyone encontered a battery draining problem when plugging in a scanner? I've had a battery drain problem lately and am trying to track it down. Any suggestions? Any wire harness trouble spots you have found in the past as a place to start?

Thanks,

[Mr_Roboto]

I do roadside assistance (i.e. I jumpstart cars with dead batteries). I have concluded that a number of unexplained drains are caused by relays sticking closed, which keeps circuits on that should be off.

[cdnsarguy]

On the older vans there were some lights ie glove box, brake or under hood that would stay on occasionally. We isolated the bad boys by hooking up a test light from the + terminal on the battery to the disconnected main power wire.......you should have a light on. Pulling fuses one at a time until the light goes out, check the fuse schematic it tells you which items are on that fuse........kinda narrows it down.