Tailgate not opening issue, do I need a new CCM?

**rickmcc** · 10-07-2020,08:18 AM

Looking a bit of help.
Recently acquired my R32, however I soon found out that the tailgate would only open when the ignition is switched on!

Turns out someone had previously wired the badge handle to the ignition as a fix because it wouldn't open!
I've reversed their work and re wired it as factory but on operation of the handle I'm getting nothing to the lock.

Done the following tests;
Tested lock, forced 12v at the lock (connector pin 3): lock opens.

Lock switching on boot light when opened.

11.5v present at handle switch (white wire): goes to 0v when handle operated.

Put 12v to the blue/red wire at the comfort control module: lock opens.

Used obdeleven to test if the CCM is recieving signal from badge handle switch: Appears to be receiving it ok.

So question is what's my next step?
I messed about a bit with the coding, switching rear lid functions off and back on but made no difference....
Am I looking at a new or possibly second hand CCM to fix the problem?
If I got a second hand CCM can it be coded with my existing long code to work with my car?

Sorry for the long post! Hope someone can help!

**VAG-Abound** · 10-07-2020,08:30 AM

Did the hacked wiring bypass the CCM to directly connect handle and lock?

When you rewired it did you have original wiring diagrams and did everything match ip?

**rickmcc** · 10-07-2020,08:35 AM

Yeah, he basically cut the live feed to the handle switch then spliced the live to the switch into an ignition 12v wire at the rubber boot. Then took the switched live to pin 3 at the lock.
Was easy enough to re-wire, as I could see where he'd cut the wires etc...

**VAG-Abound** · 10-07-2020,09:11 AM

I guess you found the module to play with its wiring, but when looking for a new one if needed its known as the BCM, body control module.

Do you have the boot release button on remotes? That will trst BCM without relying on boot switch wiring.

Did ypu mention the boot light as a confirmstion that car knows boot is clised or open, and when to sennf oprn signal? It doesnt show as "not clised" on dash for example?

**rickmcc** · 10-07-2020,09:17 AM

Thanks, yes I have the 3 button remotes. There's no unlocking at the boot lock when the remote button is pressed.
When unlocked, the boot light illuminates and the dash shows the tailgate open notification...

**VAG-Abound** · 10-07-2020,03:41 PM

I think you're exhausting my attempts to show it isn't the BCM.

When testing the blue/red wire, was that pin 8 after unplugging it from the 8-pin BCM connector? Can you pop out, cut (you'd have to rejoin it afterwards of course), or tap into that wire and see any activity on it?

Might also be worth having a look at brown+blue on pin 8 of the 18 pin connector which I think should signal boot open / closed as a separate contact (but interlocked to light switch). I think it'll be OK if you get the boot warning on dash only at the right times.

**rickmcc** · 10-07-2020,04:04 PM

Thanks for the input, I used this thread as reference: Golf mk5 boot release fuse?
So just to clarify, I hold down the middle button on the key and I get a flash of the turn signals, but that's all. The badge handle still doesn't open the lock.
If I force 12v to the blue/red wire it opens the lock.
I'll have a look at those wires as you suggest, but surely if the convenience control module is recognising the badge handle switch is operating then it must be failing to send the required pulse to the lock?
Thanks.

**rickmcc** · 10-07-2020,04:15 PM

https://photos.app.goo.gl/9FmQs8bPtnMtoKy6A

**VAG-Abound** · 10-07-2020,05:00 PM

Originally Posted by rickmcc

...but surely if the convenience control module is recognising the badge handle switch is operating then it must be failing to send the required pulse to the lock?
Thanks.

I tend to agree. The light flash is pretty convincing that the car knows what it is trying to do. Just trying to rule anything else before you go to the trouble of buying and fitting a replacement part that doesn't fix it. On a completely different piece of kit (laser printer) I thought I'd worked out what was wrong and fitted a replacement part this week, but still have the same not-working symptoms.

I'd want to check whether the internal parts are trying to send the 12V to pin 8. Cover off, check with multimeter if the 12V appears, but a cracked track or pin is stopping it getting to the outside world. The red/blue wire is connected to that pin? Not been shifted around by someone?

**rickmcc** · 10-07-2020,05:06 PM

Originally Posted by VAG-Abound

I tend to agree. The light flash is pretty convincing that the car knows what it is trying to do. Just trying to rule anything else before you go to the trouble of buying and fitting a replacement part that doesn't fix it. On a completely different piece of kit (laser printer) I thought I'd worked out what was wrong and fitted a replacement part this week, but still have the same not-working symptoms.

I'd want to check whether the internal parts are trying to send the 12V to pin 8. Cover off, check with multimeter if the 12V appears, but a cracked track or pin is stopping it getting to the outside world. The red/blue wire is connected to that pin? Not been shifted around by someone?

Good advice, thanks. Gonna try and get another look at it when I get home.