BMW Repair: BMW, 1988 bmw 735i, bmw 735i

Question
Ok so my 1988 BMW 735i is giving me major problems. When I leave the battery connected over night it dies, also it will not start on occasion it does turn over but will not start. Only on cold days though if its 70 and sun shining she fires right up. But let it be 5 in the the morning and a good 35 she wont. The windshield wipers have also stopped working. Do you have any idea whats going on?

Answer
I think you need to have the battery checked first to make sure it is ready for the changing season.Checking all your wire connections to the battery/starter,the battery ground to make sure it is clean and not green.The relay for fuel pump/DME may need changing as well.If there are any metal relays  they should be replaced as the tend to corrode inside with the electrical arcing of the contacts.The wiper issue maybe cleaning the pivots or seeing if there is power to the motor when turned on.