fng from az with a electrical problem

Hey I'm new to this forum so I'm saying what's up! I have a 98 tacoma 4x4 5 speed reg cab.

My electrical problem is that when I first got my truck I tried to put 4 off road lights on the front bumper. Well once I got them all hooked up and working I noticed that when I turn them on my fuel gauge drops to empty and when I turn the lights off it comes back up to full again. I'm guessing that I just don't have enough power and the fuel gauge is the first thing that gives up power so the system can power the engine. So I thought adding another battery would solve the problem. This weekend I got another battery , put them together and I still have the same problem. So I was wondering if anyone has had this problem and if anyone has some advice it would be greatly appricated.

 

You probably tapped into the wrong circuit. Recheck your connections.
make sure you uses relay to power your lights.