Only ones I have seen are in Fords. The switch is located behind trim panels in trunks or behind the glove box in trucks..
An inertia switch in any vehicle will be related to the air bag module.
If inertia deploys the airbags, you have more problems besides resetting a switch.
These are also tied to the roll over status right? I've only heard of one non subaru vehicle owner who some how tripped the roll over sensor and had all sorts of issues can't recall what the end result was but I do recall him narrowing it down to the roll over sensor either going bad or some how getting tripped up.