DIY: MK5 steering wheel on MK4

Disclaimer: Any modifications are at your own risk. I am not liable for any damage or harm that may occur from following this DIY.
If anyone has comments on something incorrect or suggestions to make this better, PM me.
Tools Required:
wrench 10
Small screwdriver
12 point (also called triple square) socket M12
Socket wrench
Soldering iron
Side by side comparison

1. Unhook the car battery.

2. Turn the steering wheel 90 degrees to the side. On the back there is a slot.
Insert the small screwdriver and then press down to release that side of the airbag. Turn 90 degrees and release the other side.


3. Unplug the Steering wheel loom harness connector.

4. Unscrew the steering wheel bolt. and remove the MK4 steering wheel.

5. Pull up on the yellow part of the MK5 airbag plug. Then you can pull the airbag plug out.

6. Pry up with the screwdriver on the MK4 airbag plug.

7. Cut the 4 wires from the MK4 steering wheel loom connector, leave about 5cm of wire on the connector.
8. Cut 4 wires from the MK5 steering wheel loom connector, also leave about 5cm of wire on the connector.

9. Making the custom Loom:



The MK4 connector has 5 slots for wires, I have named them A,B,C,D,E from the left. There are only 4 wires in the connector, The wire that sits at the most outside edge is A. E is an empty slot without a wire.

The MK5 airbag plug has numbers 1 and 2 written on it.

Solder A to the wire coming out of the MK5 plug 2
Solder B to the wire coming out of the MK5 plug 1

The MK5 airbag has 2 black wires, one has 2 spots it is connected to the airbag, one has 1 spot.


Solder C to the wire with 2 connections.
Solder D to the wire with 1 connection.

Use heat shrink tubing to seal your connections.

10. Plug in the MK5 airbag plug into the MK5 airbag.

11. Put the MK5 steering wheel on the MK4 steering spline (due to the clockspring the car on, it will only fit one way) and screw the bolt tight. The MK4 steering wheel bolt has blue locktite on it from the factory, you can apply some also.

12. Connect the custom steering wheel loom you just made.

13. Push the airbag into place, it will just click and lock itself.

14. Reconnect the battery.

15. Start the car from the passenger's seat, just in case the airbag goes off.


16. Enjoy the new look and feel of your MK4.

I realize this thread is 6 years old but I'm going to revive it just because:

This looks to be a much easier way to install a steering wheel with controls then other DIY's I've read about replacing stocks and spacers and cutting steering columns....

I don't know much about the mkiv controls, but if those 8 buttons are just different resistances, and one of those airbag wires is a usable ground, then you just might be able to activate those controls on your after-market stereo. You could use that 5th unused pin (assuming the clockspring has a wire inside for it), and then translate the resistances on the wheel to something useable by the headunit as per the following link:

https://forum.arduino.cc/index.php?topic=230068.0

button functions could be easily reprogramable in software and you could get those 8 buttons to do whatever you wanted on the resitiometric function list.

Hi, can you help me please, my mk5 airbag is different, this have two airbag connectors green and orange, and this have four black wires, how can I connect this whit my mk4 harness? Thanks

Pay attention to the 1 and 2 wires on the Mk5 airbag plug. There is an inductor in series with one, and to match the inductor location on the mk4 circuit that bit it important( the No.1 pin goes to B, the No.2 pin goes to A). Or so I am going to assume it is important. I just did this to my '04 and my son's '00. Needs the single-stage/single plug airbag of course. took apart a Mk4 connector, and then a spare Mk5 and then checked the spare Mk4 harness to be sure where the Mk5 inductor pin went to.

These instructions match up, and keep the inductor in the same position in the circuit.
cheers,
Douglas