MKIV Jetta - HID Retrofit - TDIClub Forums Apr 23, 2018MKIV Jetta - HID Retrofit Upgrades (non TDI Engine related) www.tdiclub. Economy - Longevity - - Motocontrol 9004/9007 wiring harness Auto to 5/6 spd manual swap with wiring instructions for MKIV. Click here. VWVortex - MK4 Jetta OEM HID (pre-03) Rheostat Wiring Jun 06, 2012From the few posts I have found it appears Pre-03 Jetta HID's with the externally mounted ballasts are easier to wire the rheostat. Unfortunately I cannot find a clear answer as to how to wire or which pins to use. I have searched and found several people that reference the install, but have yet to find definite answer. There are plenty of posts referencing the 03+ internal wiring change.