The surface of the heater pad during installation
WARNING: This page is about a different car, the 2004 Volvo S40, 2003 Volvo S40, 2002 Volvo S40, 2001 Volvo S40, and 2000 Volvo S40. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
There must not be any bubbles or kinks when the heater pad is bonded to the foam filling. Bubbles and kinks increase the risk of damage to the pad during use. This applies to the entire surface, but to the heating wires in particular.