Odd FM Reception Problem after sub install

[momalle1]

I installed the subwoofer kit from OEMAudio+ in my 2017 GT Premium last weekend. It's a nice setup, it sounds good and the only permanent mod to the vehicle is a cut in the firewall plug. That said, I know have serious FM reception problems. Stations that are normally strong are now very weak, they are mostly fuzz, some are in and out but none are clear. If I remove the power fiuse for the subwoofer amp, everything is normal. I figured the amp's power wire might be routed too close to something so I started looking around and in the process open the trunk. The reception went back to normal. I've rechecked the ground wire, tried grounding it to another location with no change. I then completely removed the wiring harness from the trunk lid and laid that in the trunk (I have not performed the recall) with no change. If I start to lower the trunk lid, the reception goes out again so basically, leaving the trunk lid in the fully open position is the only way to get full FM radio reception with the subwoofer amp powered up. I did call OEMAudio+ and the support guy referred the case to an engineer but I'm hoping somoene here might have an idea about this.

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[StangTime]

That's odd. The FM radio antenna is located in upper rear glass area. The first two copper lines (like the defroster lines). The antenna wire connects to the glass near the roof on the drivers side. Is it possible you may have accidentally disconnected the antenna lead that goes to the head unit? Check where it goes. Does it pass the trunk lid support arms anywhere? Maybe it's being pinched or pulled when closed? Does the trunk lid need to be open all the way for reception to return?
The other thing it could be is radio interference from the new amp. It's likely a class D amp with a switch mode power supply. If these are not filtered correctly they can basically jam radio signals. So it could also be a faulty amplifier as well.

 

[momalle1]

That's odd. The FM radio antenna is located in upper rear glass area. The first two copper lines (like the defroster lines). The antenna wire connects to the glass near the roof on the drivers side. Is it possible you may have accidentally disconnected the antenna lead that goes to the head unit? Check where it goes. Does it pass the trunk lid support arms anywhere? Maybe it's being pinched or pulled when closed? Does the trunk lid need to be open all the way for reception to return?
The other thing it could be is radio interference from the new amp. It's likely a class D amp with a switch mode power supply. If these are not filtered correctly they can basically jam radio signals. So it could also be a faulty amplifier as well.

Thanks, I doubt anything got disconnected as it works normally when I remove power from the amp, or have the trunk open all the way. I'm thinking the new amp may have something wrong with it. I did lift the rear seat and decklid trim to access the speaker connectors to tap a speaker level signal.

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