Cadillac 2006 XLR Owner's Manual page 137

Cleaning the System
The radar can become blocked by snow, ice or dirt.
If so, you may need to turn off the engine and clean
the lens.
The lens is located on the driver's side of the front fascia.
Clean the surface with a 50/50 mixture of isopropyl
alcohol and water on a dampened cloth. After cleaning
the fascia lens, try to engage Adaptive Cruise Control.
If this does not fix the problem, you may have to remove
the fascia lens and clean the inside of the fascia lens
and radar lens.
To clean the inside of the fascia lens and radar lens,
insert a screwdriver or similar object into one of the small
slots on the inboard side of the lens and pop the lens out.
Clean the surface with a 50/50 mixture of isopropyl
alcohol and water on a dampened cloth. After cleaning
the lens, set the lens back in place and press until it
snaps in.
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