I have done this now on a handful of Toyotas and finally got around to doing my Taco. This guide should get you hardwired for any GPS that has a cigarette lighter plug.
I am using the Garmin 205W, but most other brands can be done like this as well. It took about 1 hour for me to do, and you can expect it to take no more than 2 hours if you have not done this before.
Checkenmunga put together a more time consuming How To: Hardwire your GPS for those that want it installed in the center of the dash.
I take no responsibility for anything that is damaged during your install. Breaking off clips and other things are not common for the 05-09 Taco but I am NOT responsible if you take this on by yourself.
This is truly not rocket science. Should not be difficult for those that have a background in electronics and somewhat more difficult for those brand new to wiring.
This can be reversed with about 20 minutes to put everything out. Should be back to stock in no time.
GPS Power Cord (not pictured)
12V Power Outlet (Available at auto stores like Checker, AutoZone, etc. I used the Victor 05349-8 from Checker)
Mini Add-A-Circuit (Part # FHM200BP from Checker)
Shrink Wrap (not needed but makes for more secure connections)
Electrical Tape (if you don’t use shrink wrap)
Electrical Spades (3 flat/blue and 1 open/blue. Blue is for 14 gage wire. I’m not sure the name of the flat ones)
14 gage wire (any color)
1. For this step you will need the 12V Power Outlet, the Add-A-Circuit with the 7.5 & 3 amp mini fuses, some of the 14 gage wire, shrink wrap or electrical tape, and 2 electrical spades that are flat.
Take about 12 inches of 14 gage wire and splice it between the 12V Power Plug and the Add-A-Circuit to the red or “hot” side of the Power Plug using flat electrical spades. Add the electrical tape or shrink wrap, seal the connections (Pictured below on the left of the 12V Power Outlet). Add the 7.5 amp mini fuse to the bottom plug (looking at it with the prongs down) and the 3 amp above that. Make sure that these are not broken before you add them as they are difficult to remove once in.
2. Next you will need the 12V Power Outlet with the Add-A-Circuit attached, 3 feet of 14 gage wire and 1 open ended electrical spade.
Splice the 3 feet of wire to the 12V Power Outlet on the white or “neutral” side of the Power Outlet. Attach the open ended spade to the other end of the 3 foot of wire (Pictured below on the right of the Power Outlet). This will be used for our ground and attached to the frame of the truck.
3. Next, remove the O-S&!t handle by popping of the two covers and removing the bolts with a 10mm ratchet. Once the 2 bolts have been removed from the handle, the side panel should easily slide out. Go ahead and remove this now. Being careful here is VERY important if you have the side impact air bag as this may deploy if hit hard enough.
4. Now you can pull the coin tray on the left of the steering wheel out by slightly opening the door then lifting up. Once removed you should see the fuse panel with some open slots waiting on us to install our GPS.
5. Insert the GPS power cable (the end that plugs into the GPS) along with the open ended spade ground wire up through the far left of the dash so you can reach it were the O-S&!t handle is supposed to be.
6. Attach the ground wire to the bolt holding on the side curtain airbag. If this is not an option, you will need to find another location for grounding the white wire to the chassis.
7. Place a few zip ties along other wires to hold the ground wire into place. Near the bottom of the opening, secure both the ground wire and add the GPS power cable with enough slack to be run at the base of the windshield and up to your GPS (See picture for more detail).
8. Plug the Add-A-Circuit into the open fuse location shown below. The one selected was chosen because it turns on only when the key is turned to the ON position. Using the multimeter I was able to determine this. You can choose another open one if it works for your liking. I believe there was one on my panel that was on all the time.
9. Plug the GPS power plug into the newly installed 12V Power Outlet and test it to ensure it turns on when the truck is on, and off when the truck if off.
10. If everything works like you want it to, you can start to coil the excess wire together and find somewhere to stuff it all. I was able to stuff it on the right of the fuse panel and zip tied it to another bundle of cable to keep it in place. I think there might be enough space on the left of the panel as well but I did not see anything to secure easily to.
11. Put everything back together and install the GPS unit to the power cord.