Rear speakers and Sub not working. A4 B6

[starnon]

Hi, I've posted a similar thread in the B6 section, but was suggested I post here too.

The rear door speakers and sub are not working in my 2003 A4 Avant, they have never worked since I bought the car and was looking into wether I can test the amplifier to see if it's busted.

I was testing it today, the power from the battery is getting to the amp. Strange thing is that I reckoned I could bridge the connector to the amp (after disconnecting it) and let the head unit power the rear speakers without the amp (just for testing sake) but I couldnt get any of the rears or sub to work. I was using the following diagram and bridging the rears, ie 1 to 20 and 2 to 21, but no sound.
Any suggestions? Also, any ideas on how to test the amp if it's working? Seems odd to me that the input doesnt seem to work (unless i'm doing it wrong..)

BTW, it's all standard RNS D/symphony (not bose) setup.

 

[AndyMac]

You can't test the speakers by connecting the inputs to the outputs, and you might have actually damaged the HU by doing so. The line inputs are low level unamplified signals (pre-outs) which need an amp in order to drive the speakers.
You can test the speakers by disconnecting the multiplug and connecting an AA battery across the +ve and -ve terminals of each speaker, you should hear an audible pop. Or better still connect a multimeter across them and check the impedance - it should be 4 ohms.
If you get no reading then the speakers are open circuit and this is the problem. If the speakers are OK then it has to be the amp. There's no real way to test the amp on its own unless you have a test rig. I've got a spare working amp from my B6 non Bose you can have for £25. Let me know
Cheers, Andy