NO SIGNAL all of a sudden. Gone. Lost.

I WOULD GUESS A NEW UNIT .SORRY

check fuses to radio.
check connector at radio.
if all that is good, radio is bad.

does it hold any memory, ( i.e BASS / TREBLE settings etc...?)
if not, pull the head unit out & swop the RED & YELLOW wires over, either by cutting them and re joining them red to yellow & yellow to red, or by pulling them out of the ISO block & switching them over..

do u have the navi adapter or is it built in

I have a 3 year old Sportster 2 replay unit that worked perfect until 1 month ago. I posted my problem on this website a day before you did with this same problem. I googled to no end and even spoke to Sirius who wasn't willing to replace my unit at no charge since it was out of warranty. I found an unusual solution on the internet that worked for me. I place my receiver in the freezer for at least 20 minutes (this was recommended by a guy somewhere on the internet with the same problem). I have actually left it in freezer overnight too. This has solved my problem. It is the craziest thing but I thought I would try it before I resorted to replacing all my accessories and receiver since Sirius was less than cooperative with the issue. Anyway, hope this helps.

It's a Bad SIRIUS Tuner. there have been lots. If it's in warranty, have it replaced. if not, you can still find that unit for around $50 from Crutchfield etc. Hope this helps.

The nav feature is purchased separatly with the deck, the previous owner did not purchase it because at the time alpine was charging an extra $1000 on top of the price of the deck to add nav. This is due to the fact that alpine decided to use there own reasearch and development team to design a nav system where as kenwood baught the rights to use garmin's technology and put there name on it which they only charge $400 on top of the price of head unit to add nav.

http://search.sirius.com/search?q=Alpine+099+series+software&site=default_collection&client=default_frontend&output=xml_no_dtd&proxystylesheet=default_frontend&entqr=0&ud=1&sort=date%3AD%3AL%3Ad1&oe=UTF-8&ie=UTF-8

I also had this problem. I had to go through the menu into the setup and then into tuner settings. There should be an option called tuner area. If you set it to area 1 it should start working. For some reason the sirius only works on area one. Hope that solces your problem

the only thing left is the head unit but that is not very likely. Go back to where you bought it from and have them give you new tuner box and anttenna. Sorry man But i put these in all day and its almost impossible for the head unit to be the prob