Hi, I’ve moved away from the very loud music but some sometimes it get turned up but then I’ve only 3 cartridges so total collection of 18 CDs anthems, techno, summer in Ibiza... even trance.
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If the original sub amp and it’s speakers have had it, then there are s/h units on eBay some times.
But it’s easy to pick up the existing wiring that’s in the tailgate for a replacement amp, what ever the size, you will find at the rear of the tailgate two of the amp services that are required, one is the audio pair and the other is 12v amp switched supply, both of these can be extended to the location of your amp, (both of these feeds can be found at the rear of the head unit where they originated) if required.
Then all that required (depending the amp size) is the 8mm/10mm 12v+ fused supply directly from the battery to the amp location.
Then it’s just the subwoofer speaker box plus it’s pair of wires to the amp to be connected. Job done.
With the option to retain a functional tailgate amp just T into the audio and with the amp switch-on supply introduce a two-way switch into its feed, so either the tailgate is switched on, or the replacement amp is switched on.
Some thing I did around 13 years ago with the disco, and still working