2.8 CD V6 Auto won't start, reversing lights on in Park/Neutral

[bluebus]

I am unable to get the engine to start in either Park or Neutral. It would appear the gear shift interlock has been disabled due to the reversing/parking lights being engaged. I am suspecting the transmission range sensor has developed a fault presuming it also acts as a reversing switch? Can't seem to find much information online and the Haynes manual has limited information. Has anyone come across this problem before?

[SilverBeast]

Look at post 6 on this thread and see if that helps.

http://www.fordgalaxy.org.uk/ford/index.php?/topic/24421-immobiliser-issues-with-galaxy-19-tdi-automatic/?hl=%2Bauto+%2Breverse+%2Bswitch#entry173239

[bluebus]

Look at post 6 on this thread and see if that helps.

http://www.fordgalaxy.org.uk/ford/index.php?/topic/24421-immobiliser-issues-with-galaxy-19-tdi-automatic/?hl=%2Bauto+%2Breverse+%2Bswitch#entry173239

Thanks for the link but I had done this a few days ago after having intermittent starting problems thinking that this may be the cause. However the difference here is that the reversing lights are on when either in Park or Neutral and the moment they extinguish she starts up.  I had some success by dropping out the 15amp fuse from the central box but now even this fails to work. One other point of note is that at times recently when the engine was idling say when coming to a stop and in drive the reversing lights would come on activating the parking sensor display. My theory is if the TRS acts also as the reversing switch that by being energised when in either P or N it inhibits start up as if it was physically in gear.

[insanitybeard]

In all seriousness, if you've got an intermittent electrical short e.g in the tailgate wiring loom where it passes from the body into the tailgate, it could be causing the reverse lights to come on and as a consequence disable starting, I'm not entirely sure how the reverse lights are switched on the auto boxes but it may be worth checking this before going too deep, wiring breaks and shorts within the wiring looms where they pass from the body into the doors and tailgate are common due to the flexing of the cables which weakens and breaks down the insulation over time.

[bluebus]

Thanks for that insanitybeard. I shall double check this just to cross this one off the list but somehow I doubt that this is the problem in this case as the lights go out from N to D then back on when thrown back into N. I had the TRS out last weekend and fiddled around by disconnecting and reconnecting and the lights went on and off so definitley connected to throwing on the reversing lights. It's a sealed unit with 7 wires and 2 sprung loaded prongs with electro plates on the end so I presume the prongs connect to positional points within the sensor as they are forced in and out by a block within the box (as seen through the sensors port) when moving the gear selector through it's range. I am looking out for a spare at the moment which is proving to be difficult.

[bluebus]

Still no luck I'm afraid in sourcing a replacement and my local Ford and VW outlets are not able to get a new unit in until the New Year and at a hefty cost. Is there some way I can bypass the switch without cutting any wires or is the ECU geared up to know if something is amiss?
I have checked for any intermittent electrical fault where the looms pass through to the tailgate and unable to get the lights to either switch off or flicker so I am now convinced either the TRS is faulty or perhaps the ECU has developed a fault. I have just bought a VAGCom but have yet to use it. Could someone give me a head start on the procedures in using this and point me in the right direction to source any malfunctions or codes for the autobox etc?
Thanks.

[SilverBeast]

VAG-COM/VCDS-Lite help is in the FAQ's/Reference Library section of the Forum.

I usually stick the fault codes into google and pick a result that is on the Ross-Tech site (they wrote the software). There is a Ross-Tech wiki that you can use but I usually find google easier.

I expect there is a connector for the loom into the hatch from the main loom in the right rear cubbyhole in the load area.  I would disconnect that connection, if there is just to eliminate the possibility of it still being the tailgate wiring.  Ideally find which wire is for the reversing lights and see if the +12V that turns them on goes away (on the loom side not the hatch side) when you disconnect the connection. That would indicate it is probably being driven by a short in the tailgate loom.  If that is the case you may be able to start the car with it disconnected.

[bluebus]

Finally got to the bottom of the problem and yes the TRS was faulty. Managed to source a replacement on ebay for a tenner inc postage, swapped over and bingo, no reversing lights on in either Park or Neutral and she fired up first time. Happy days