How to test DWA and seat control module?

[540i94]

My 540i 94 keyless entry remote didn't work and the front seats, side mirrors moved to opposite direction. The dealer told me I have to order a new key to correct the remote key problem and I did. But, the new key still didn't work. I left my car to the dealer for 2 weeks. When smoke comes up on my head, the manager said I have to replace DWA module (keyless remote receiver), which cost $600+ and the seat control module $600+.
Can anyone help? How to test the DWA and seat control modules, before I put myself on the butcher's table, again?
I need a detail instructions, where the modules and how to remove/install them. Thanksss...ssss!

[SharkmanBMW]

My seat memory buttons got sticky and the seat would not respond or would do weird things... dealer wanted big$$$
I cleaned the memory buttons and got them unstuck and now all is good...
could be irrelevant to your situation... dunno