Reading lights and sunroof not working

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Hi, I noted that my sunroof and the reading lights only (courtesy are fine) for the front cabin only are not working. The bulbs, fuses, relays, are OK. The buttons for sunroof, front reading lights, and all courtesy lights (center button) are not doing anything when I press them.

The dealer told me that the computer says something about ¨low power (voltage)¨. The only ¨upgrade¨ I did to the XC90 is that I installed standard HID lights for fog, low and high beam, and also I installed it 1 pair of HELLA halogens with HID lights too; so, all was very well, but since a couple of weeks I have the problem.

The battery that my XC90 is using is almost new, and I have no error codes shown in the cluster.

I appreciate your help! Regards.