Rain is killing me

[E-series ftw]

I had similar issues with my 4.8i E70 when I bought it. It did not run, but it was trying to start. At the end of the day, the completely sealed DME box was half full of water and the VVT module was completely full of rusty water. The DME is not a sealed unit so water didn't stay in the module. I had to replace the VVT module and soaked all the DME and VVT connectors in pb blaster for about 4 days, as they were all green. I had to poke a hole in the bottom of the DME box to drain it out and I'd guess about a gallon of water came out. ISTA showed a DME box fan activation error (obviously). 4 days afterwards, I blew the connectors clean and they were all back to a shining copper colour. Reinstalled a dry DME and an eBay VVT module and it started right up!!
I am however still chasing a strange interior lighting issue, where all the overhead console switch lights and the 2 ambiance spot lights are on permanently. BMWteka doesn't show the wiring diagrams to the overhead console (says it's under revision), but I didn't find any evidence of water ingress in either the FRM or the JBE modules. I'm suspecting I may have to to a reprogram on the FRM to see if that solves it. The previous owner complained of a battery drain consistently having to boost it, so that may have caused some issues with the FRM.

But anyway, you should definitely check the DME box for signs of water.