z4 3.0 2003 electrical problems

[oliviasz]

Electronic all out of whack. Started with dash lights and radio.battery drain to where new one is dead in 2 months (garage stored. I know, not wise to not disconnect. Should have learned after 1st batt replacement) Now problems wiith radio, airbag light, remote everything, check engine light, top u/d, airbag light-FIRST to come on. Researched. Airbag control unit or short or something else? Nothing all at once slow then rapid decline.

 

[Ewazix]

Welcome to the forum, sorry to hear about problems. As you say leaving it for 2 months can kill most batteries, better to fit a battery conditioner like
the CTek.
I'd start with basics like checking the battery IS good and fully charged. A Voltmeter on the terminals without the engine running looking for about 12.4 ish Volts. and with the engine running to test the alternator where a healthy alternator should be giving around 13.7v at idle and not much over about 14.5v preferably. Then check what current is drawing after shut-down, if it's excessive remove fuses one by one to isolate the offending circuit.

Anyway common drains on the E85/6 seem to be caused by audio kit/connections for iPod etc which prevent the systems from shutting down, defective audio head units remaining live (warm amp), heating fan final stage resistors (the 'hedghog') failing, trunk (boot) light or other interior lights staying on.

If all else fails it's a trip to the auto electrician :|