I just recently installed a MTX 6500D and 2 10W3 and tonight I dediced I would go into test mode and check my voltage. To my suprise with the volume 3/4 to full it was around 18 volts. This doesn't seem normal to me, and I'm wondering if it could be a bad ground connection. The other thing I noticed is my headlights dimm like crazy! Is that normal for a mid-sized class D amp to do that on a larger electrical system?
Thanks for you help!

 

If your headlamps dim, then you are experiencing a voltage drop. 18 volts would give you very bright lights.