Went down to auto barn the other day and bought a cat 10 for ($200) went home and connected it up as per instructions ect and it wouldn't work

then about 5mins up the road it works fine! now this morning does not work again and wouldnt work after 5mins ect so i pulled out everything again

checked all connections and everything was good but still no go, got out my multi and cheked the internal power supply/Earth of the unit and all was good but i could not test the output (the part that connects to the head unit) so i assumed the item was faulty, and took it back down to autobarn, Now when i got down there they told me that CATS are not compatible with VR/VS calais?statesmans due to the BCM but on the back of the cat it says VR/VS models, it only mentions that its not compatible with kenwood and jvc or something) but my clarion unit is fine! So now my car is in bits and with no sign of being able to use the steering controls anymore

: Does this sound right? or does it sound like autobarn is feeding me garbage? cheers!!