stereo problems
 

I have an aftermarket stereo in my 98 Jetta TDI, a Pioneer DEH-P350. The other day it just up and died on me. I took it out and all the wiring is fine, so then I had Car Toys test it, and they said the unit works, which means something is wrong in the car. The Car Toys folks told me that sometimes a stereo will go into "safety mode" if something is wrong with the wiring anywhere else in the car. I checked all the fuses, and I'd rather avoid tearing out all the wiring in my car if possible. Has anyone had a similar problem that they fixed, or have suggestions?
Thanks much