GPS and Outside Ambient Air Temp
This is the add on module you need for both RTX and HDX series gauge clusters to have your speedometer controlled by GPS data. Some transmissions do not have a cable driven speed output. It also may be that if you are running a modern drive train that the speed cannot be pulled from the ECU or that data is not recoreded to the ECU you are using. If any of that is the case this is the expansion you need. Not only will you get a nice accurate speedo, but it also has the outside ambient air temp incorpertated into this expansion module which will also display on the Dakota Digital dash. It comes with with everything you need to connect to your Dakota Digital or ATP custom gauge cluster.