When I bought my truck last week, it already had an aftermarket tape deck that hadn't been installed properly so I had a bad starting point. Basically on "tape" mode only the front speakers worked, but on radio all of the speakers worked.
I installed a new Sony Xplod CD/MP3 player (150 bucks from supercheap and it came with a remote an' everything. Nice) thinking that I'd solve the problem but I had exactly the same thing.
After doing a bit of reading on here, I realised that the SSR-G comes with a factory amplifier that runs the rear speakers, as well as an electronic aerial that comes up when the radio's on. What it took me a while to figure out was that you have to connect the "Aerial remote" and the "Amplifier remote" from your new stereo together and then connect them both to the single remote lead from your car (usually blue) that operates both the aerial and the rear amplifier.
It took me a while to figure it out because the new stereo thinks of the aerial and the amplifier as two separate units whereas the hilux treats them as one. When I first wired it up, I hadn't connected the amp remote lead from the stereo to anything (thinking I didn't have an amp) so when I switched to radio, the head-unit would say "aerial on" which would then make the aerial go up AND turn the amp on. When I switched to CD, the head-unit would say "aerial off" which, with the amp lead disconnected, makes the aerial go down but also turns off the hilux's amp so I only had the front speakers when listening to a CD.
If I'm going through the bush/car-wash and want to listen to the cd player but have the aerial down to stop it getting damaged, I guess I'd have to use the stereo's settings to turn off the amp. This would turn off the amp and also drop the aerial when listening to a CD.
Hope this saves anyone else from hours of frustration!
P.s. I had to file down the plastic at the sides of the dashboard stereo mounting in order to get the stereo to fit in there in the first place. Fun.
