Pete, I had the same problem, first when I put my 2 10'* in the trunk and then again when I put my pioneer 6x9'* in. Both times I re-calibrated it according to the manual and it'* worked fine since. I actually went out a couple of times before doing any speaker upgrades. I think as soon as the compass loses it'* bearings it shuts itself down. Just love the looks I get driving around in circles when I recalibrate.

My compas didn't shut down... it is just way off. Like when I drive towards the lake it says I'm going SW....

That'* nothin - once my compass started turning backwards!

Well I was going to calibrate it today, but noticed it started working again by itself! Well, I looked closer and noticed it wasn't just right. It was completely opposite. I was going North and it said I was going South.

Oh well, for now I'll deal with it. Not like I need it now. Plus it'* too darn cold to be outside laying in my trunk to relocate the sensor.

it'* not like it'* a very "nice" compass just the main cardinal directions.... Do ya really use it?