Need help troubleshooting - front speaker problem

[NorthWestv2]

Evening all,

Hoping someone with more knowledge than I have on car audio/electricals can tell me how they would troubleshoot my issue, but some backstory first:

Like many, I needed more from the stock car audio so followed Dellmassives stage 2 upgrade:

Audio Upgrade Stage-2 - Vibe Micro Amplifier Plug & Play - How I Done It -

Audio Upgrade Stage-2 - Vibe Micro Amplifier Plug & Play - How I Done It - ************** . Audio Upgrade Stage-1 . . . . Blam Relax 200rs Speakers From Skipton. . Audio Upgrade Stage-2 - Vibe Micro Amplifier Plug & Play - How I Done It - . Audio Upgrade Stage-3 - Vibe Micro Sub Amp + Jbl Sub -...

www.t6forum.com

Everything ICE related in my T6.1 startline was stock at this point, wasn’t concerned about blowing stock speakers if it happened.

Stock head unit with Nav just like this one but without USB connection on the face:

6.5" Original Head Unit With CarPlay Android Auto Radio For VW Golf Mk7.5 Transporter T6.1

Audio Tech Direct - UK Specialists in In-Car Entertainment. We offer a huge range of car stereo’s from single DIN units, double DIN and car specific units plus a huge range of stereo accessories!

audiotechdirect.com

Fitted the Vibe micro amp 65.4 with the plug and play wiring harness I bought separately, bizarrely had no issues with room for the amp and harness behind the unit which seemed a common issue.

Much more power and better quality from the speakers with HPF turned to low/off on the amp.
Then I noticed a few days later the passenger front speaker was quiet, shifted the fader on the head unit to full passenger side and volume up it’s barely audible.

Thought maybe I’d blown the speaker so ordered some Vibe speakers which was the plan all along and today I swapped the stock speaker I thought was blown for one of the new Vibe speakers..

New speaker is also very quiet so clearly old speaker wasn’t blown but thinking bad wiring harness, bad amp or blown fuse.

So my questions are how can I find out (without buying a second amp or a second wiring harness) if my issue is with either of those?

Also on the fuse side, I’ll look to replace them tomorrow too just in case, does anyone know where and which fuses to change?

Thanks in advance!

 

[The Flying Scotsman]

I’d try swapping the speaker wires on the amp.
This would tell you if the speakers were knackered or the output from that channel on the amp has little or no output.
Even connect wires an old speaker and try it in each speaker’s output of the amp.

 

[Howzat]

Unplug the quadlock from the amp and plug back into headunit. If you get even volume in both speakers from the headunit then it's the amp.
It wont be a fuse issue.

 

[NorthWestv2]

Thanks guys will try both suggestions tomorrow, just thinking, if I take the amp out of the picture, use original wiring/quad lock into head unit and both speakers work it could still be the wiring harness (damaged wire or poor connection) and I’d need to know or find out which wires within the harness are for left/right speakers.

 

[Howzat]

https://vibeaudio.co.uk/wp-content/uploads/2019/08/Powerbox-65.4-amp-manual-050418.pdf

 

[NorthWestv2]

I’d try swapping the speaker wires on the amp.
This would tell you if the speakers were knackered or the output from that channel on the amp has little or no output.
Even connect wires an old speaker and try it in each speaker’s output of the amp.

Would a multimeter tell me if the amp has gone if I find and unplug the left and right speakers at the amps power/speaker terminal block (8 or so wires that connect directly to the amp) but keep the power etc cables connected?

The actual left/right speaker connectors are about 30cm further down the wiring harness so I’m trying to rule out dodgy connections or wires by testing as close to the amp as possible.

 

[Howzat]

Speaker connections? Did you not buy the VW Plug and Play amplifier Kit that comes with a specific VW harness?

 

[NorthWestv2]

Yeah, the T harness is what I have, but bought it second hand so trying to rule out that being the issue or the amp being the issue.

Essentially there are three harnesses: stock harness from ecu with quad lock (male), T connector with quad lock (female), amp harness.

 

[Howzat]

I really doubt it's an issue with the harness then, especially as it was working fine for a few days. Much more likely the plug on the amp itself. I've had the same amp fail on me there but was totally losing audio when mine went. Wiggling the plug in the back of the amp would get audio back only for it to cut out again. New unit fixed that issue.