Lost parking sensors after installing aftermarket head unit

Hello:
The other day I had installed an aftermarket head unit to replace the Top HiFi OEM Alpine radio on my 2008 328i (E90).
After reading several posts, I had the OEM head unit relocated to the trunk, and I had several wires run to it, including the High and Low CAN bus.
I then had an additional speaker installed in the empty center channel to take care of the chimes warning for opening the door while ignition key is in, parking brakes and seat belts.
My car is also equipped with rear parking sensors, that I thought go through a different loop. However, I have now realized that I lost the parking sensor beep.
Maybe is something as simple as having to reprogram the car, but I am afraid to have lost them for good.
Does anybody on this clever forum has any info, feedback, suggestion? Thank you.

It turns out that the problem was that I did not connect the rear signals from the OEM radio to the central speaker. Now I get the beep but it is way too weak. I will have to find the way of in-line amplifying it.

Originally Posted by Antidogma

Hello:
The other day I had installed an aftermarket head unit to replace the Top HiFi OEM Alpine radio on my 2008 328i (E90).
After reading several posts, I had the OEM head unit relocated to the trunk, and I had several wires run to it, including the High and Low CAN bus.
I then had an additional speaker installed in the empty center channel to take care of the chimes warning for opening the door while ignition key is in, parking brakes and seat belts.
My car is also equipped with rear parking sensors, that I thought go through a different loop. However, I have now realized that I lost the parking sensor beep.
Maybe is something as simple as having to reprogram the car, but I am afraid to have lost them for good.
Does anybody on this clever forum has any info, feedback, suggestion? Thank you.

Top HiFi = Logic7
Logic7 = center speaker

If your OEM system is in fact Logic7 then how are you getting rear analog outputs off the OEM Professional radio when the outputs are MOST digital? How that OEM center speaker is not there?

Your system is HiFi, and the rear outputs of the Professional HU are analog, low level, balanced. That's the reason of the low volume... those are not speaker level signals.

Sorry about the confusion. My system is HiFi. And you're right, the signals from the OEM radio are now not amplified, but I can still hear the chime. However, even after connecting the rear speakers to the same dedicated central channel for the chimes, the beep from the parking sensor is still very weak.
I am considering the purchase of a small motorcycle amp to boost up the chime/beep signals.

Originally Posted by Antidogma

Sorry about the confusion. My system is HiFi. And you're right, the signals from the OEM radio are now not amplified, but I can still hear the chime. However, even after connecting the rear speakers to the same dedicated central channel for the chimes, the beep from the parking sensor is still very weak.
I am considering the purchase of a small motorcycle amp to boost up the chime/beep signals.

As stated before: the aftermarket amp has to accept balanced inputs.

I am not running the aftermarket amp for the chimes. The aftermarket amp is connected to the aftermarket head unit.
The OEM radio was relocated to the trunk and I installed an additional speaker in the empty center channel that is dedicated to the CAN BUS coded signals.
But, as you stated, the signal from the OEM radio are low level, balanced signals. I am considering boosting them up with a small dedicated motorcycle amp.