Car sat for a couple months. Charged up battery. Cranks but won't start. No codes. Initial diagnosis led me to finding the green wire to the coils does not have 12 volts on it when key is on.

Checked the associated relay, and it has 12 volts at pins 1 and 5 as it should. Swapped relays, and no change. Jumped relay pins 1 and 2, and the car fired up.

Pulled the JBE to check for water damage even though the floor has never been wet. A couple pins had very minor white corrosion, but nothing major. Pulled the JBE apart and there is no corrosion, burnt pins, or dry solder joints, but of course with the double board you can't see all of it. Cleaned up the minor corrosion and reinstalled it. JBE main power input has 12.5 volts.

Still no joy. The front wipers also don't work, but the rear one does. The windows work. HVAC works.

Anyone have any thoughts on were to go next? Clearly the JBE is not activating the relay to the coils, and the wipers don't work so that seems like the JBE is where the problem should be.

 

Assuming a standard Cube Relay with standard pinout (30, 87, 85, 86 nomenclature)...

I would meter the JBE socket, including the ground pin. I once correctly diagnosed a bad Jeep fuel pump because the ground pin (85) was NOT grounded. The fact that you have other peripherals not working leads me to believe that there is an issue with either the ground pins or the constant power (line) pins. I imagine both are connected and fed through some kind of bus. Dollars to doughnuts something is going on with either the Constant Power bus or the Ground bus (which may be either internal or external to the JBE). This is an educated guess not derived from real-world Mini Cooper experience. So forgive the generality of my comment.

Good luck!

D