Sub fitting
Posted: Fri Oct 09, 2026 7:59 pm
Hi all,anyone trying or thinking of fitting a sub to a late 24 on Polo GTI, here is my experience. Firstly I already had a good Kenwood under seat sub from my previous fitting in a 2014 Scirocco using a T junction quadlock connector, so I was able to remove & put wiring back as standard for selling with no issues on installation or removal ( this will be relevant later) Having been lucky enough to purchase a brand new Polo GTI in June this year, I set about researching & collecting parts to install Sub ! I looked on this forum as was able to find out about getting power lead through bulkhead & removal of glovebox to access rear of MIB unit to fit later 52pin T harness £40 to keep all factory wiring intact etc ( this had LOC to go sub & had ignition feed to trigger sun also. This lead also had 60ohm built in resistors to avoid any warning lights or insulation issues etc. Right now for the fit. Disconnect battery (in boot) left it for 1/2 hr or so before unbolting passenger seat ( to make access so much easier for sub & wiring fitting. Remover panel down side of centre console & glove box to access MIB ( you need radio keys to pull this forward & out for “T” harness etc. I had run power lead down N/S sill under panel ok & RCA lead & trigger wire along centre console. Earth was made/drilled near N/S front seat mount. All went together well & sub worked ok. I did not have to re set much,clock & tyre monitor only.BUT “SOS” restricted warning on dash & red light next to overhead console button. Had this scanned & said there was an open circuit. Got some suggestions from a few companies that retrofit etc. Some sugesed bent pins/ poor fitting or locking of quadlock. Finally got a sensible possible solution. On the quadlock going into rear of MIB unit remove 2 x lower green & blue micro blocks & replace with 2 removed from car original, bypassing “T” harness cable. This cured it & didn’t need codes or fault erasing!! I have rung harness supplier to get them to update notes for this. Turns out VW measures resistance in leads & thru up warning. Sorry this is so long, but hopefully this is helpful & may well apply to other model with sos system etc.