2010 Volvo 780 electrical issue

Hi everyone, hope that all are good. I have owned my 780 for going on about 4 years. I have been having this issue with my truck since I bought it. When I first start my truck up in the morning, the read out on the dash for the volts reads 13.9 to 14.1. However, once I start turning on headlights and a/c both cab and sleeper, it will drop to 12.2 and sometimes even lower. I have 4 brand new batteries (950) and a brand new heavy duty alternator that I purchased directly from Volvo and I am still having the same issue. When it gets down into the 12.2 range I hear a faint beeping sound and the light that indicates that the bunk a/c is on, starts blinking. If I just turn the a/c in the bunk off and leave the lights on and the front a/c, it will read from 12.5 to 12.7. I am going nuts trying to figure this out. Anyone ever have anything similar to this? Would greatly appreciate any information that can be passed along. BE SAFE EVERYONE!!!

 

Thanks I will give it a shot. I will let you know what I find.

 

I asked a buddy of mine and he told me the same thing. He said to try bypassing it and if that was the problem, replace the switch. I appreciate the info, I will let you know what I find, thanks.

 

Thanks for the reply, that’s what I was thinking. I will attempt to search for it and I will let you know what I find.