Avic D1 source Problem in Ford F-350

I have had an Avic D1 installed in my 05 Ford F-350 since last August. A local installer put the unit in. We also did the bypass on this unit with the extra ground wire in the harness. Every thing has been working fine. Althought we do have one problem that happens sporadically. The source will change involunatrily . Usally when I hit the horn a few times it will change, or step on the brake changes it , also when I have a trailer hooked up to the vehicle and the plug from the trailer is connected, it always changes to another source when the brakes are applied. About a month ago on a long trip out west it started to automatically switch sources with out doing any thing, matter of fact it would constantly scroll through all sources until I lowered the screen and then it would stop. It did this for a few days then stopped. Any suggestions on how to trouble shoot this problem, would be greatly appreciated. Maybe a better ground ?

do u have any steering wheel remote adaptor hooked up?

Yes, they installed some PAC unit, that interfaces with the factory steering wheel radio controls.

which model steering wheel interface are you using model number # ?Luis

Sound Waves

Is up to the installer to test all wires with a DMM whenever possible.

It is the               PAC SWI-PS Pioneer Sony Steering Wheel Interface

i dont like using the pac units ...they usually have a horrible delay also. unfortunately most shops only carry it or the peripheral (which is the same units). If u have no luck w/ it...try the one through soundgate.

Thanks, for the info, I will try and have this unit reprogrammed or look into the other unit. I think first I will disconnect the controller and see if I can recreate the problem.