This is gonna be a long shot, but here goes.

As some people know I've been doing LEDs for members here and have been taking apart nav units. A lot of nav units. I came across this problem recently.

The radio buttons do not work except volume **** and the seek ****. The radio will not turn off with the volume ****. The radio is funtioning. We know this because we used the steering wheel controls.

I tested the circuit board that I did the LED swap for on my own car and it works, but it will not work on the other unit. This rules out the circuit board being a problem. We also swapped out the units from both cars to rule out that the wires are tampered. It's for sure the radio portion that is busted. Somewhere is blocking the signal from the circuit board to the radio unit.

Several questions I have that might be the problem.
1.If you use a electric drill with a magnet bit, will it cause any problems if you touch the wrong thing ie, resistor or part of the circuit?
2.Using a circuit board from another nav unit to replace the original. Ie- my old car was a 2007 is350 which I took the radio portion circuit board and put it in place of a 2011 is350 radio. Will that cause the radio to malfuntion?

Senario- I used a 2007 is250 radio circuit board and put it into a 2006 is350 radio. Now the buttons on the radio do not work on the radio unit except from the steering wheel. The thing is I've swapped my own is-f with a circuit board from a is350 and it works perfect.

If anyone can shed some knowledge, thanks!