. I got mine from Rocket Ron from this forum ( VW Endangered Species ).
Bear in mind any extra cables you might want to add. Always a good thing to send him
your original loom as a pattern because the looms vary over the years.
I threaded a single strand of domestic 2.5 cable through the 2 parts of the chassis that you need to get through and
taped the new loom to them in turn and pulled / threaded ( very gently !! ) the new loom through.
I started with the rear of the loom , pulling from middle of bus towards the back of the bus.
Then I pulled the front of the loom from the middle of the bus towards the front.
The headlight loom is separate so make life a bit easier at the front.
Take the time to tape the loom to the cable properly and securely without increasing the thickness too much .
I had a nightmare when the cable I attached to the loom came off in the chassis.
Took me ages to 'fish' it out.
The hardest part of the chassis to get the loom through was the by the front beam which is where I lost the pull cable.
I'm not saying I did it the best way but it worked ( eventually )
One thing I can say is to borrow an extra pair of hands and don't try to rush it , take it all slow and easy, which I'm sure
you will once you've shelled out the cash for the loom you won't want to damage it !!
Good luck