Safely drilling holes in floor of vehicle

[Svenn]

I thought drilling 3" vent holes in the floor of my new Toyota SUV would be straightforward, like in the bed of the truck I had before, but on inspection there is a LOT of stuff both above and below the floorboard, not to mention I can't really tell if the floorboard is double-plated... so even if it looks like a clear place to drill, I'm scared I'll hit some wire or something sandwiched between. 

Does anyone have any tips for this?  Should I go to a Toyota shop and just ask the mechanic if he knows a safe place to drill without hitting anything?

 

[highdesertranger]

what SUV is it and what year? highdesertranger

 

[TrainChaser]

Just my opinion: Body shops probably know as much as a dealership, and ask a lower price.

 

[Optimistic Paranoid]

Crawl under the vehicle and drill up?  Be sure to wear safety glasses while doing it . . .

 

[GotSmart]

In my experience holes in the bottom of a van tend to cause problems with exhaust getting in.  

Make sure you can seal them up while driving.

 

[Svenn]

what SUV is it and what year?  highdesertranger

Highlander hybrid; basically a big Prius- LOTS of stuff above and below... most of it the giant battery bank.

 

[Svenn]

Crawl under the vehicle and drill up?  Be sure to wear safety glasses while doing it . . .

I thought of that- I could just drill with a small bit first and see if it's double plated or not; if it is I could epoxy the hole closed, if not I could then try to drill the 3" hole.

 

[tx2sturgis]

Have a fire extinguisher ready!