Secrets of the C4 Rear Hatch Wiring

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • UrS4boy
    S2Forum Obsessed
    • Feb 2006
    • 11859
    • Country: Canada

    #1

    Secrets of the C4 Rear Hatch Wiring

    Scenario: Your rear wiper or your rear hatch defroster or your back-up lights no longer work on your C4 Avant/estate/wagon. You start trying to figure it all out. One thing that you will have to do is to pull the rubber grommets at the upper left side of the C4 hatch. You will be looking for broken wires to fix (solder and heat shrink or crimped butt connectors, etc.)

    As I investigated the cause of the failure of the rear wiper motor on my 98 C4 A6q avant, I took some photos of the wiring, in case I wanted to do a write-up. So here it is:

    This is what I found when I pulled the rubber boot out the hatch: 12 wires:

    Focus on the first six on the left side of this photo:



    Focus on the second six (right side of the first photo):



    I made notes as to where I thought the wires went in the hatch but a few disappeared. So I dug out the Bentley and found the appropriate section X 1032 to X 1035 and traced the wires by colour to their devices. This table summarizes that info:



    Here are the devices on the left side of a LHD hatch, i.e. the fog light (the white bulb holder) and the left side back-up light (the black bulb holder). "TheCrisplyNoodle" from the UK with an UrS6 tells me that the RHD version is very similar, with the exception that the fog light harness extends over to the right side of the hatch.



    Here is the rear wiper motor harness connection (blue/yellow, brown and red/yellow):



    Here are the devices and the sub-harnesses on the right side of a LHD hatch (the lock position switch sub-harness is under the brown zip tie at the top left of the photo; the luggage compartment load area light switch sub-harness is the black one on the right side of the photo, the right side back-up light is the black bulb holder). A RHD hatch would have the empty socket in this photo filled with the fog light lamp holder that the LHD cars have on the left side of the hatch:



    Here is a closer shot of the hatch lock transition harness:



    Here is a closer shot of the luggage compartment switch sub-harness where the brown/white wire becomes a green wire:



    Wiper motor wiring is shown on pg. 53/53 of this pdf:

    Last edited by UrS4boy; 19 October 2013, 16:52.
    RS2'd 93 UrS4 5 spd sedan
    94 UrS4 V8 6 spd manual avant
  • macspring
    S2Forum Zealot
    • Mar 2005
    • 6371
    • Home: Ireland Current: Wallis & Futuna

    #2
    Very nice write up.

    Mods - Sticky ???

    Comment

    • UrS4boy
      S2Forum Obsessed
      • Feb 2006
      • 11859
      • Country: Canada

      #3
      Just added this:

      Here is a closer shot of the hatch lock transition harness:

      RS2'd 93 UrS4 5 spd sedan
      94 UrS4 V8 6 spd manual avant

      Comment

      • UrS4boy
        S2Forum Obsessed
        • Feb 2006
        • 11859
        • Country: Canada

        #4
        C4 Rear Trunk/Boot Light wiring

        I *was* guessing that the wiring would be the same or similar for the sedans but someone just made me confirm it via the Bentley:

        Rear Fog = L20 = Grey/white, pg. X94, Track 571

        Back-up Lights = M16 (left) = Blue/red, pg. X70, Track 253
        Back-up Lights = M17 (right) = Blue/red, pg. X70, Track 254

        Rear Trunk lock Alarm swith = F124 = Brown/Grey enters trunk, goes to White/yellow before switch = pg. X83, Track 415
        Rear Trunk lock Alarm swith = F124 = Brown/Green enters trunk, goes to White/black before switch = pg. X83, Track 417

        Hope that helps.
        RS2'd 93 UrS4 5 spd sedan
        94 UrS4 V8 6 spd manual avant

        Comment

        • K7ERG
          S2Forum Extremist
          • Mar 2004
          • 1711
          • Country: Scotland

          #5
          I had the rear wiper fail on mine. Swapped the motor no difference. Checked wiring behind rubber and found a broken wire. A fairly common thing I think on these old avant c4s

          There had also been a repair on the same wire once I got it out from a previous owner/ garage.

          Good write up and helpfully once again.
          Audi A6 AEL 5cyl Quattro breaking.
          Audi A5 3.0tdi Quattro Stage 2
          07947385043

          Comment

          • caterpillar
            S2Forum Fiend
            • Jun 2004
            • 2480

            #6
            thanks for sharing pics and info....!! i do like this forum...!

            Comment

            Working...