Dual Batteries

[broken_con]

I recently purchased a 1996 GMC Sierra 2500. It came with dual batteries. The first time i took it on the freeway i drove for about 45 minutes or so. After sitting in the parking lot of the mall for about an hour or so it would not start. Upon inspection i discovered the aux battery was smoking and smelled of rotton eggs! Luckily (and not so luckily) we were next to the sears so i purchased a new one. still would not start. tested the main battery. dead cells. replace it. no problems since.

 

Questions:

I had no problems prior to this. came out of nowhere. just like that, both batteries wasted! how could this happen?

Why dual batteries?

Is this aftermarket? its not a diesel

Truck doesnt seem to function with only one (either one) of the two batteries. Why?

 

Any advise appreciated

[whmayhew]

If it has the snow plow prep package it would have two batteries. Probably the battery on the drivers side was dead and if the other battery is connected directly to the main one it will not give you enough battery power.

[broken_con]

If it has the snow plow prep package it would have two batteries. Probably the battery on the drivers side was dead and if the other battery is connected directly to the main one it will not give you enough battery power.

 

<{POST_SNAPBACK}>

 

 

 

I know the previous owner used it to tow alot and at one time had a camper shell on it. i assume this is why they added the second battery. but how do they work together? nothing seems to work if they arent both connected.

thanks for the input