Batteries Draining?

[Big T]

So my son says that after the Haida headlight install his batteries are draining overnight. I asked how his alternator is and he says it's showing 13+ with everything on.

How do we test if there is a load being drawn on the batteries when everything is supposedly off?

 

[THEFERMANATOR]

I always start off with the test light method myself. Disconnect both positive terminals, then connect one lead of the test light to one of the battery positive terminals, then touch the probe end to the positive cable. If it lights up you've got a sizeable current draw, if it doesn't then there shouldn't be a big enough current draw to kill a battery in less than a few days. If it does light up, start unhooking things until it doesn't, when you find the one that makes it not light up, you've found your big current draw.

 

[WarWagon]

Recheck wiring for headlight install. Any relays put in? (Sticking, miswired, etc.)

Typical draws are glove box light, dome lights coming on in the cold from bad switches, map light left on, vanity light on sun visors, horn switch sounding the horn when cold at night, ignition switch, failing brake light switch bringing on the brake lights or leaving them on, miswired radio/alarms.

How old are the batteries? Separate and test them the next morning for one going bad taking the other down with it.

 

[ak diesel driver]

I had a slow drain it turned out that the relay that was prewired in my driving lights was miswired.

 

[Big T]

I always start off with the test light method myself. Disconnect both positive terminals, then connect one lead of the test light to one of the battery positive terminals, then touch the probe end to the positive cable. If it lights up you've got a sizeable current draw, if it doesn't then there shouldn't be a big enough current draw to kill a battery in less than a few days. If it does light up, start unhooking things until it doesn't, when you find the one that makes it not light up, you've found your big current draw.

Thanks. Good suggestion.

I'm suspicious of the HID relay harnesses and the All 4 on Hi Relay, as my son left them in a bucket out in the weather. Should be very easy to find using your suggestion.

The lights are working and the headlight housings are nice for the HIDs.