Help! Truck Keeps Draining Battery?

[Oxygen454]

Hi guys, new to the forum.

 

My truck seems to be draining the battery over night. This has happened in the past and turned out the glow plug relay kicked the bucket. We replaced the relay last year. Now the truck is having the battery drain again but I am not sure if this is the cause again. Is there any way to check the relay? Is there any common problems that drain the batteries other than the glow plug relay on these trucks?

 

Any help MUCH appreciated as I rely on this truck for work.

 

The truck is a 2002 GMC Sierra, 6.6L Diesel (dually)

 

As a side note, there is no check engine light and my OBD2 reader is not picking any codes up.

 

I am not a mechanic but I do know my way around engines and vehicles as I work on mine and friends.

Thx!

[8.1HD/ALLISON]

Need to perform a parasitic draw test and isolate the draw to a certian circuit.

[Oxygen454]

Hi thanks for the reply. I will try isolating the draw by unhooking all the add-ons on the truck. Also thinking about testing the glow plug relay and doing an amperage test between the batter and battery connecting wire. Both of the batteries were replaced last year so they are both new and under warrenty.

 

Need to perform a parasitic draw test and isolate the draw to a certian circuit.

[belandguy]

That happened to me on my 94, ended up being the starter that was draining the battery, after changing it, it never drained again