Originally Posted by johnyoung39
I've tried to jump the 12V but I am not getting any dash lights to come on at all. Could there be a fuse that is preventing the power from reaching the control systems?
I had to look up what a "Halo" is. Its claimed "57,720 mWH" (i.e. thousanth-of-a-watt-hour) of power is in more plain language, 57 watt-hour or a minuscule 4 1/2 amp hour at 12.5 volts. That can't begin to charge a completely dead car battery which can be 50 to 100 amp-hr.
Sure, it might have the current capacity to provide the 150 amps for a few seconds to turn a car starter, but that does not mean it has the energy storage to charge a totally discharged car battery to any degree.
Buy or borrow a voltmeter/multimeter and check the battery voltage. 13.5 or so is fully charged, but anything over 12 volts should be enough.
If voltage is low, try jumping it using ordinary jumper cables from another car. Watch the polarity! Leave them connected and the other car engine running for 10 minutes.
Alternatively, buy or borrow a 12 volt battery charger (a little few-amp one will do) and leave the charger connected until the battery is charged.
If the battery is dead and the car has been in below freezing temperatures then the electrolyte probably froze (it is plain water when 100% discharged.) and the battery is ruined.
I think I recall that the battery positive terminal has fuses? I doubt any fuse blew, and if it did, it indicates a bigger problem.
If the battery is good, then it could be a wiring harness fault. Smart ED's have a history of wire chafing and breakage problems in the right rear quarter panel area - behind the interior trim in front of the right tail lights - but we are nowhere near checking those more serious differential diagnoses yet.