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Discussion Starter · #1 ·
I will install (hard-wire) a Tomtom GPS this weekend.

The spot left next to the A-pillar looks perfect and I expect that flow from the air outlet will hardly be affected.

The plan is to have the wire go straight down to that it will not be visible at all, and connect it to the car's power. This should satisfy my wife's demand that it all look neat :eek: and hopefully discourage thieves.

Any suggestions and pointers will be gratefully accepted, in particular as to :
  • where to take power (I would like to make this a fairly professional installation -i.e. if not to complicated I want to take power from the fuse-box - otherwise I may have to revert to stealing power from the back of the lighter-) and
  • How best to open the dashboard - that is the part directly under the windshield
 

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For the top of the dashboard where the speaker grills are, that just pries off. There is also a closeout panel on the side of the dash, hidden when the door is closed, that you can also remove using a knife. Then it may be easier to snake wires.

Depending on what power you need, that may be more difficult. The radio and many other things like the accessory outlets are run with constant power. The radio turns off after the ignition under control of a serial data bus message from the body control module (BCM) under the rear seat.

This design makes sure that the ignition switch isn't used to run ALL the possible loads through it when it's turned on. The switch is unreliable enough the way they designed it, and excess load would only make it worse.

But a GPS load isn't that much, so you might just tap into the brown wire under the steering column coming out of the ignition switch contact assembly. That's hot during ACCY and RUN modes. You can tap into that circuit also in the rear fuse block fuses 29 (Rain Sensor), 33 (Front Wipers), or 31 (TBC ACC). A circuit hot during ACCY, RUN, and START is on the white wire on the ignition switch harness, or rear fuses 47 (IGN 0), or 50 (TBC IG).
 

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Discussion Starter · #3 ·
...You can tap into that circuit also in the rear fuse block fuses 29 (Rain Sensor), 33 (Front Wipers), or 31 (TBC ACC). A circuit hot during ACCY, RUN, and START is on the white wire on the ignition switch harness, or rear fuses 47 (IGN 0), or 50 (TBC IG).
Thanks for all that information.

Is there any way I can tap from the front (i.e. engine compartment) fuse block ? That would seem to be only inches away from where I need power.
 

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Annoyingly enough, NO circuits under the hood are active in ACCY modes. Assume you want the GPS to work in ACCY mode and not just RUN mode.

But if you want RUN mode, then go under the hood and tap into fuses 22 (IGN E), 16 (TBC IGN 1), 27 (BACKUP), 28 (PCM 1), 54 (AIR SOL), 53 (O2 A), 54 (O2 B), or 26 (ENG 1)
 
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