Before attempting to separate the assembly I will try the solvent coated pad and magnet technique. Accessibility is the only constraint when using this technique.
This has been done many ties, Accessibility is not a problem, I highly advise doing this with the unit removed from the car.
By "solvent" , I hope you are referring to ethanol or 95% iso.
DO NOT, I repeat
DO NOT use acetone unless you desire a nice warm glow from your headlights.