dash illumination out after nav?

Installed an eclipse 5435 nav unit in my 08 Toyota Tundra. Everything went good... everything works well. Except for my dash button illumination.

The wiring diagram I used noted 2 illumination wires (orange and sky blue) at the factory nav harness. I tested the orange... it worked on my head unit.... also tried the blue, worked as well. So... figuring they're both +12 (as the diagram stated), I tied them together and spliced both to nav illum wire. Illum on unit works as it should.

The next night is when I realized that when I turn the parking light circuit on.... the clock/outside temp display goes out... the climate control digital display goes out... and none of the dash control switches illuminate (although they all still function properly).

After much searching I found some different wiring diagrams that identify the orange as illum -

Question is: Could splicing these together have somehow backfed voltage through all my switches illumination circuits and fried them!?

If yes... then why did the orange wire power up the nav illum when I tested it?

All fuses are good. I have tested all the individual illumination wires going to the switches and they have +12v. Ground wires have continuity as well. I have yet to get any continuity through any of the switches illumination/ground pins.

Thinking more and more about the above facts... and I do believe I just fried about a thousand dollars worth of gear in a brand new truck. Anyone have any other ideas? Thanks.

I have tried just the orange... worked fine (dash illum still out) and I have tried just the blue... same result.

Right now I am using just the blue as that is the wire that my current diagrams id as + illum.

The only time the dash buttons are supposed to illuminate is when you turn on the parking/head lamp switch.... so the problem is all the time.

In other words.... the won't illuminate at all. What is a little strange is the clock and outside temp work when light switch is off... but once you turn the lights on it goes out.

I thought(and i could be wrong) the truck has two parking light wires. One is positive when the switch is on and the other negative thru the potentiometer and varies ground when you adjust the dash lights. If the dash lights are turned low it could show positive. This could be bad if this is so as you applying power to it from the other wire could have done damage to the truck. I recently had an installer fry something called an interior light module on a new Yaris when he miss-connected a parking light wire to this second parking light wire and the final cost to repair the car was over 600 bucks...

I'm assuming when you say "parking light wire" you are referring to the illumination wires correct?

The initial wire diagram just showed both as "+11-14v w/ ignition switch on".

The second diagram showed the sky blue going into each switch and exiting out the orange wire. The rheostat was on a different page, and didn't look as though it also was fed by sky blue, exiting to orange.

If I did fry all the led's inside each switch... I'm looking at about $2000. The climate control unit goes for $1000 by itself. What stinks is that all the switches still function.... they just won't light up at night.

You would think that they would have a diode on this wire to prevent something like this.