Head unit wiring hard to figure out

GORDYDJ

Active Member
Mar 9, 2024
79
8
I have a MK2 Leon with the 1 din Blaupunk CD/radio.
I have an Android HU. I bought a patch lead which was labelled as compatible with the MK2.
The picture below shows what I received.
IMG_20240515_184023~3.jpg

For a start these blocks are too big. Even the cables approved by Connects2 are the same. Meaning even if I spend the £40+ they charge I would have a big rewiring job to do.
Second, pin 14 has the yellow lead. Pin 16 has the black lead. But on my car pins 15 and 16 are the power pins and the earth on pin 12. With pins 9 and 10 being CAN+ & CAN-. Also included was a red & a brown lead not connected to anything.
Up until now I either bought a patch lead, connected one end to the HU and the other to the car and it just works. Or a HU with the correct wiring and fascia included.

On the loom included with the last HU I bought. I have the yellow and the black wires on the power side. But I also have a green and a white wire. All four go into the plug of the canbus adapter.
IMG_20240515_194059~2.jpg

The red wire in the pic only goes between the HU and the canbus adapter.
Can anyone offer any advice. I'm not buying another HU. I have 3 already 😐
 
Last edited:

R3k1355

Active Member
Oct 30, 2014
1,800
253
Yorkshire
I'm pretty sure you need a Quadlock to ISO connector for the power and speaker wires, and then a Fakra to DIN adapter to do the aerial antenna.
 

GORDYDJ

Active Member
Mar 9, 2024
79
8
Thanks for your reply. What I need I Can't seem to find.
I have bought from Connects 2 in the past. Had no problem with their leads. Apart from the fact that om my 3 previous cars I could never get the SWC's to work.
This is what Connects2 have for my car. And was confirmed by email when I queried it.
CTSST001.2.jpg

I just know that there's no way those power & speaker connectors are going to fit anywhere.
Surely Connects2 of all people should know this?

This s what i bought off Amazon. Also confirmed as compatible with the Leon 2.
41kgYdrGsuL._AC_SL1024_.jpg


As mentioned in the post above the speaker & power connectors do not fit the quadlock. I guess the red & the brown wires are for CAN+ & CAN-.
I think I'm going to need someone to advise me on which wire goes where. And just do it myself.
Just entered quadlock to iso connector for seat leon mk2 into google. And the results were just as above.
 
Last edited:

GORDYDJ

Active Member
Mar 9, 2024
79
8
Looking at the connects2 quadlock. It has pins in 9,10,12,13 & 15. Surely there should be a pin 16?
 

GORDYDJ

Active Member
Mar 9, 2024
79
8
So now I'm starting to get somewhere. I've bypassed the canbus adapter by removing the black, yellow and red leads and inserting them directly into the quadlock. Hopefully it doesn't turn out that I need the adapter
Is anyone able to advise what leads go from the ISO connector to CAN+ & CAN-?
The only drawback I've found is the HU doesn't turn off with the ignition. I reckon I can live with that.

Luckily I have plenty of those wee wire connectors I can scavenge from previous HU wiring looms.
 

GORDYDJ

Active Member
Mar 9, 2024
79
8
Yes that's probably correct. Unfortunately I blew the under bonnet fuse before I could try it and I don't have a spare. I'm pretty sure no one around here would have one. Especially on a Saturday. I don't remember seeing that type before.
 

tafakasam

Active Member
Aug 12, 2017
45
2
West Yorkshire
Switched and permanent live might need to be swapped, they always used to on older VAG stuff.
+1 its the case for older VAG cars.

but with newer VAG cars due to canbus, a direct feed is required for the switched live (i think) or perm live (cant remember) to the fuse box so when ignition is off the stereo turns off with it.

been a while since i last faffed around with headunit change in a canbus car, tend to leave factory unit even though i have had the itch to change to a carplay one for past 2 years but want to leave it all stock instead lol
 

GORDYDJ

Active Member
Mar 9, 2024
79
8
been a while since i last faffed around with headunit change in a canbus car, tend to leave factory unit even though i have had the itch to change to a carplay one for past 2 years but want to leave it all stock instead lol
That's what vehicle designers want you to do. Hence they make it difficult to fit aftermarket units. Though in many cases aftermarket looks much better than stock.
 
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