My Corolla came with a standard radio and I wanted to upgrade to factory navigation so I bought a used factory nav unit from a reseller. The basic installation went according to plan (I had to wire in my own GPS antenna) but was hoping that the head unit itself would be plug-and-play using the connectors behind the dash. I learned that Toyota used different wiring harnesses depending upon what came original equipment and because my car was a base unit it was missing a harness required to make the GPS work, called the "K3" connector on the back of the nav. I had to purchase a K3 harness separately and wire in a signal from the handbrake and a signal for vehicle speed. The speed signal proved most difficult to locate, but I finally found a good source under the hood, tapping the wire bundle running to the engine management controller near the battery.
Once all that was in place, everything worked as it should - including turn-by-turn voice commands from the navigation lady - and it looks 100% correct with a fascia/filler panel I picked up from the local Toyota dealer.
Once all that was in place, everything worked as it should - including turn-by-turn voice commands from the navigation lady - and it looks 100% correct with a fascia/filler panel I picked up from the local Toyota dealer.