Your choose: HiFi (676)/HK (674) add-a-sub harness/LOC

HiFi (676)/HK (674) add-a-sub harness/LOC

(5 customer reviews)


HiFi(676)/HK(674) harness/LOC is used to add a trunk sub/amp to the OEM amp. Remote signal included.

Harness plugs in between the OEM amp and LOC converts the high-level OEM amp woofer signal outputs into low-level aftermarket amp signal inputs for a subwoofer.

Kit includes:

  • HiFi(676)/HK(674) OEM amp add-a-sub harness

Standard LOC75i:

  • 75W max input PnP LOC with signal sensing remote turn on 12V signal output

Premium LOC100i

  • 100W max input PnP LOC with adjustable gain control and signal sensing remote turn on 12V signal output
  • 24″ RCA cables

All OEM speakers remain powered by OEM amp after HiFi(676)/HK(674) add-a-sub harness is connected.

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Installation: unplug OEM amp, plug harness in between, plug LOC to harness.

Please note that this harness is not compatible with Top HiFi 677 and 688 Digital/MOST Top HiFi/HK/Logic7 OEM systems. This harness does not replace the HiFi(676)/HK (674) OEM amp.

Additional information

Weight .5 lbs

5 reviews for HiFi (676)/HK (674) add-a-sub harness/LOC

  1. Damion Morrison (verified owner)

    This harness looks just like the picture above and works as plug and play like described. There are tons of forums out there that have positive reviews for this product and it’s amazing. Coming from someone that never does reviews I’m extremely satisfied with this product and his communication. The item took about 4 days to arrive once shipped and the packaging was well secured.

    • technic-pnp

      Thanks for your order. Much appreciated!

  2. Alex M (verified owner)

    This Harness/LOC was one of the easiest installs I have done to my 2012 BMW 328i. It was as simple plug and play. The only hard part was accessing the stock amplifier. This harness was a much cheaper alternative to paying a shop to install my sub and amp. Overall, I’m very satisfied with the product and the shipping was very quick.

    • technic-pnp

      Thanks for your order… much appreciated.

  3. jamionl20 (verified owner)

    Fast shipping, product arrived and looked just like the picture. Everything was plug and play. Extremely satisfied and will definitely recommend. Again, extremely satisfied customer here, 5 stars all day long. My only suggestion would be to make some shirts available, hats, decals or something. Thanks!!!!

    • technic-pnp

      Thanks for your order… much appreciated! Good suggestions!

  4. gungun2452

    This was by far the easiest sub install I’ve ever done myself. Got 2 Rockford Fosgate P2s w/ 1200 watt amp. It took me about 30 mins to hook everything up once I bought this harness. Highly recommend!

    • technic-pnp

      Thanks for your order, much appreciated.

  5. cassatajimmy (verified owner)

    Should have bought the harness years ago! Install was quick and easy. Highly recommend.

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