Tuner was working one day perfectly. Next day I went to 'source' and all I see listed is 'player' and 'aux'. Its quite an effort to rip the dash apart so is there anything I can check before doing that? Maybe software?

Mine has done that once or twice for no real apparent reason. Did you try a power cycle?

I don't think the tuner is listed in the boot log from memory. Not that that's easy to get of course since you'd have to get to the DB9 on the sled.

Mine does that occasionally, apparently when there's not enough voltage during boot. Try turning your key to the accessory position without turning over the engine and see if it shows up.

Tried power cycles and random removal from the sled - didn't try it in accessory position though so will try that later.

I seem to recall that it was possible for a certain component on the empeg itself to fail that would cause the tuner to stop working. You might be able to check that in a boot log, I don't remember. Somehow I doubt you're set up to get a boot log from within the car, though.

The other possibility is loose docking sled wires. So you might have to resign yourself to pulling apart the dash.

I've got a stupid question...will the tuner still show up if the antenna wire is disconnected from the antennea? I presume it would. I used to get perfect reception, now It is mostly static. Guess I am pulling mine apart!

Absolutely.

Well I'd tried all combinations of starting the car but it was still dead. Then yesterday I was at the traffic lights and tried it and it works again. I'm confused.

Bad connection somewhere which happened to get jiggled enough at the traffic lights to work again