i need to buy a tbs the dodge dealer sells for a 109.00 and autozone sells for 33.00 which is best quality

should i buy parts from autozone..

 

The Dealership will always be one of the highest prices. Most chain auto parts stores sell BWD( Borg Warner) sensors. Exception being NAPA who use Beldin/Delphi. I personally used NAPA, but to each their own. OEM parts can/will fail just like cheaper Aftermarket ones will.

 

what does the tbs do ?

 

It's TPS, not TBS. Throttle Position Sensor. And it tells the PCM what position the throttle is in.