ground wire

Installing a digital outside thermometer. The sensor in the bumper requires both a ground and a power source Same with the display. Could I connect all the grounds together and connect them close to the fuse panel? In other words a 3 wire terminal? (G G leg) More importantly, is there a problem with it not grounding close to the accessory (sensor) and having a long ground wire?   I know it would be easy to ground by the bumper, I just don't the ground close to salt and the elements in the engine compartment. Thanks for your help in advance.

Provided there is no significant voltage drop due to the long wire, no - a remote ground should not be a problem. If it were a signal ground it would be an advantage to ground remotely, ie, close to the reader. Usually a single (common point) GND is best - especially for signals. Power GNDs usually aren't so fussy except where ground loops are an issue.