1998 Subaru Legacy No Idle, Battery Power Drain

I have hooked up a faulty tacho gauge to my main dashboard and it has seemed to have broken my dash, dashboard lights don't work, revs or speedo don't respond. Main problem that i'm having is that I can't seem to maintain an idle after it fires, eventually the engine just dies and it seems that the battery is not getting charged and is losing power. Could tampering with the dashboard create this sort of problem? Any help would be appreciated! Thanks