Looses power driving down road - 2005 Chevrolet TrailBlazer

Define loosing power ? Battery dies overnight ,driving down the road ?

vacuum ? or vent line either will let you drive till see mechanic

Could be the dimmer switch. Are you loosing both high and low beam when it happens ?

With the engine running wiggle every wire connection you can find and you should find the loose connection/broken wiring.

look for a loose wire or a spliced wire that has a short

Is the check engine light on, if so I would have the codes pulled to find out whats wrong.

Have you changed the fuel filter?

alternator belt snapped ?

check for loose electrical connections at battery,etc.

Sounds like an electrical issue maybe the plug from firewall to cab is loose or on computer is loose, sometimes those coonections or pins get loose,i had a new car with 200 miles on it and it went dead in heavy traffic,had to get towed to dealer they found loose connection!!!!With audible noise when happens tells me its wiring,check all connections and wires to connections make sure there not loose!!!Best of Luck to you!!!!!