I have a Tahoe e-fan set up in my 99 Sierra RCSB with the relay's from Nelson. They have been in the truck for obout a year and a half with no problems. Now I am getting a 2 amp drop when the fan kicks on in defrost setting. My battery is also not starting the truck over night.

I have a 100 monthe diehard gold battery that was installed in May of 2008. The battery charges back up fine.

Could I need a bigger altonator so the charging system can keep up?

Maybe do I have an issue with my Nelson e-fan harnes?

What amps are the stock altonators?

Thanks in advance. Mark