This story started about a year ago.
Customers newly aquired E46 BMW quite a nice example but it had been through a few changes of owners.
Customer complaint Water Leak and sunroof won't open.
Water leak was an easy fix two of the four sunroof rain water drains weren't connected --- fixed bone dry ever since.
Tried the sunroof not even clunk when the switch is operated.
Checked fuse -- okay
Examined the sunroof
glass sealed to the body with sealer.
Before attempting to unstick the decided to check the motor and switch.
Looked at circuit diagram motor has a built in control module connected to the BMW 2nd K line but my scantool hasn't coverage of the sunroof.
Diagram showed the controls for the sunroof motor work in a similar to those used on some steering wheel audio controls, ie pushing different buttons signals the module by providing different resistance values.
Checked powers and grounds on motor and switch both okay, but no changes on the signal wires with the scope
At this point I informed the customer but with a now leak free car he decided not to spend more so simply pulled the fuse
A year later I have been tasked with getting it to work. Stripped out the switch to get at the motor and noticed the switch rattled ! I opened up the switch to find the circuit board missing !
Okay but before ordering a new one decided to test motor. With no working switch to check the motor as an assembly I found the control module can be dismounted to give direct access to the DC motor . Testing the motor by connection to 12v revealed it was burned out -- no surprise !
Currently awaiting (used) parts --- All caused by a bodged solution to two rubber drain tubes that were disconnected.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
Last edit: 5 years 11 months ago by Andy.MacFadyen.
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