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Old 07-24-2010, 08:41 PM   #100
Registered User
Join Date: Aug 2008
Location: Brampton, Ontario, Canada
Posts: 765
My Ride: 2003 325i
Originally Posted by mohan12 View Post
From initial research, it appears that the radio shutdown issue is likely (hopefully) attributed to a blown or improperly placed fuse (if it was blown or improperly placed, wouldn't the radio not turn on??). They both look fine to me, but I think I should take a closer look and perhaps swap one out with another (associated with rarely used functionality) one and see if that resolves the issue? It seems that the headunit doesn't realize that the car is on and acts as if the car is off (and thus, auto-shuts down after xx minutes.) This makes sense- I hope this is the cause.
Ahha! I think you have just debugged your problem!!! Well, narrowed it down to the 5A fuse or the connection to pin#5 (12V Acc) to the HU.

The HU will operate with the key in the off position or no key in the ignition at all BUT you will NOT get text from the PA12 when you do this.

I apologize - I should have though of this earlier.

I don't know why exactly, but the HU must ignore anything on the ibus when this happens, but it can still send commands to the PA12. btw Ė the Dice behaves the same way, so itís a car thing & not a feature of the PA12.

So, the 5A fuse could look fine but still be broken OR the fuse element may be making intermittent connections. Regardless, change it.

If that doesnít fix things then itís time to pull the HU and make sure power is getting to pin#5. If it is, check for a bent pin.

There is also a fuse on the back of the HU. I do not know what this is for or what it would do if pulled.

I believe you simply have a bad 5A fuse.

Yes, you will get a little bit of a spark when you plug the 30A fuse in. This is the constant 12V to the HU and the spark is due to the inrush current of power supply.
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