MK5 GTI Steering Wheel Controls or Horn Not Working

[Omerta11]

I’m happy to report it’s Finally Solved!!!

As I suspected, the wiring for the horn switch was wrong. As to why, I can only put it down to the guys that I got to install the Steering Control Module - they clearly had no clue what they were doing.

I analysed the wiring harness for the horn switch & airbag. Without a wiring diagram, it was hard to work out what was right and wrong. I looked online for a wiring diagram and couldn't find an exact match, but found some similar ones.

One wire looked to be plugged in the wrong connector lug based on its plug size and configuration, and another connector lug was bent out of shape. I fixed the bent lug, and looked closely at another lug on the opposite side of the unit where I suspected the misplaced wire should go - it was scored, so I made an educated determination that the wire in question had been plugged there previously. Plus, it looked like where the earth/ground circuit should be connected based on the similar wiring diagrams I was able to reference.
I took the plunge and wired it the way I thought it should be. Put it back in the car... and it all works!!!!

Car is back to normal - very happy, and satisfied I was able to work it out.

Totally furious at the guys that (incorrectly) installed the Steering Control Module...

Lucky for me, I had the time and (limited) expertise to work through the issues. Goes to show that when you want something done properly, you do it yourself - and with the help of this community!

[Transporter]

I see that you don’t need me anymore to come tomorrow.
But hey! Not that I’d want to blow my own trumpet here, but wasn’t it me, who told you that the mechanic who dismantled and installed the module most likely didn’t push the connectors back in properly?

I just didn’t want anyone to think, that it could be or was me who stuffed up!

[Omerta11]

I see that you don’t need me anymore to come tomorrow.
But hey! Not that I’d want to blow my own trumpet here, but wasn’t it me, who told you that the mechanic who dismantled and installed the module most likely didn’t push the connectors back in properly?

I just didn’t want anyone to think, that it could be or was me who stuffed up!

Definitely wasn’t you who stuffed up! And yes, you did say it was likely the SCM wasn’t installed properly. You helped me out heaps during this process - much appreciated.

Still want you to come out tmw - I still want to swap over the cluster as we discussed (if possible).

[Omerta11]

Just thought I'd do an update, purely for those of you out there who may have experienced similar issues...

A few days after I posted that the issue had been resolved, the problem came back - I lost the steering wheel buttons and horn functionality while doing a short drive across town. It stayed that way until about a week later, then they started working again for no reason. A quick switch-off and switch back on and it was all gone again. Frustrating...

Long story short for all of you, the one item that was never considered was the Steering Wheel Button Control Module that sits in the steering wheel itself. If you remove the airbag on your steering wheel, you will see ribbon cables coming from the left and right steering wheel buttons connecting to a small box at the base of the steering wheel.

I found a second-hand one from a wrecker and installed it - everything is working again.

Now, I'm not holding my breath just yet... when the issue was (supposedly) resolved a few weeks back, the issue returned after a few days - so here's hoping it will stay fixed.

Thanks to kamold for helping me out and suggesting that I look at the module.