Convertiblau! My 1996 BMW 328iC

[Jake]

Mileage: 108,700

I'm taking Blau to the Outer Banks on Thursday morning, so I wanted to make sure she was ready for some highway driving. My trip to JMU and back didn't prove any issues aside from the tonneau cover flying up repeatedly on the way home.

So, I fixed that. The top computer is most likely dead - or one of the 8 microswitches is busted. I have very little interest right now in troubleshooting given the top can be operated manually with very little fuss, but I needed a way to lock the tonneau cover down. The good news is, this electric roof is very simple in operation and only uses two motors - one for the top movement and one for the tonneau. No hydraulics involved (the E46 does have hydraulic assist and is allegedly more of a pain to diagnose).

I bought a double-pole, double-throw switch from Amazon - at "rest" the switch is centered and you can momentarily (hold it down) engage it in two directions. Went in the trunk and peeled back the carpeting on the driver's side, which revealed both motors. I had disengaged them by pulling the strap under the back seat, so I re-engaged just the motor for the tonneau - a quick push and it slots back onto the gears.

Next, I snipped the wires off of the tonneau motor's connector. There are five wires - two are a thicker gauge and colored red/black, three are thinner and various colors. The thicker two are the +12V and Ground for the motor power, and my guess is the other three are for the top computer to talk to the motor.

I got +12V from the battery, conveniently located in the trunk. Ran an inline fuse (15 Amp) and routed that wire through the trunk into the cabin on the driver's side. Ground was sourced from the airbag computer that sits under the back seat. The switch basically routes power to the motor, but is set up to reverse the polarity based on which way you press the switch - thus running the motor in "forward" or "reverse."

And hooray, it worked!

Also did an oil change (Rotella 15W-40, Bosch filter) and topped up the coolant as it was down a teeny bit from the "Cold" line. PO replaced the cooling system and mentioned how much of a pain it was to bleed. I ran the heat on the way to work yesterday and my guess is that it had a little air bubble that worked its way out. No big.