I have a 2000 E4 I bought used in 2012 that I’ve put a new charger, controller, motor, batteries, and tires on over the last year. Really having fun! From time to time over the last year, I would hear a click and the car would stop, trying to start/stop the ignition and putting the emergency brake on/off would somehow enable it to start again and all would be well. Was out for a fairly long ride the other day (charge was at 68 after starting at 100) and heard a click, things completely shut off and the display read -0015 (which I understand means a battery issue). I played around with the ignition key and it started back, however the horn sound you hear when you leave the emergency brake on was present the whole time. I had to repeat this about 5 times to go 2 miles home. During this time the display is flashing from showing the speed to off, but never shows the charge. I could fiddle around with the emergency brake and sometimes get the horn sound to stop, but it was present most of the time. Also noticed a burning smell that smelled like brakes or I guess it could be the horn as it was on for a while. I got a battery tester and checked all the batteries which all tested fine. The clicking sound is positively coming from the contactor, I think its called, its a large relay piece on the driver side under the dash.
Any thoughts would be greatly appreciated!