Connect the lead from the HU that you would normally attach to the e-brake lead to a ground point (negative) IE. Negative battery terminal, any exposed part of the frame, etc.
hid lights hid kits
Hot: 2001 Estoril M Roadster
ZCP 19's, ZHP knob, JL 8W3
Cold: 2002 TiAg M3 6mt
ZCP 19's, ZHP knob, GROM, OEM 18's,