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Lighting gremlins - assistance required!!

Discussion in 'Boxers/TR/M' started by wintech, Dec 15, 2019.

  1. wintech

    wintech Karting

    Jun 1, 2011
    206
    Perth WA
    Full Name:
    Pete K
    Hi All!
    recently began having issues with the rear lights, which led onto other discoveries. I have the '88 US version wiring diagrams which I have been poring over of late.
    For no particular reason the rear lights( tail, lisc.plate, reverse) stopped working..checked fuses. all good; however the yellow wires showed no active voltage. .32V! started looking wider and the Fuse#2 15a seems to have a short on the circuit, traced the RN1.5 to the overhead switches and seem to have a crossover affect with the RN leads at the rear connector for the tail lights...no voltage at all.
    Took all the footwell plates out to check the C4-C8 connectors as the P.side belt was cycling to and fro ( pass good, swapped ecu's over and no change)

    I now have no power to the front park lites .32v there too.

    My query is the significance of the RN1.5 wire in all of this, seem to come across it in the rear lite connectors, C8,C7,C6,C5 connectors. I have a feeling I may be on the right track, however some suggestions would be much appreciated. I cannot get power to the K12 RN1.5 due to the short (ran out of 15amp fuses)

    Cheers
    Pete K.
     
  2. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,639
    Texas
    Full Name:
    Steve Magnusson
    Can't see any (stock) relationship between fuse #2 with the RN wire and the operation of the yellow wires for the external running lights -- so will break it into 2 issues:

    Fuse #2 blowing and the RN wire -- Unfortunately, since this RN wire is always +12V, it is a likely candidate to be used for added electronics. My first suggestion would be to unplug the k connector, replace the 15A fuse, and then confirm that you do get +12V on the corresponding RN wire male pin on the fuse-relay panel that mates to the k connector without the fuse blowing (if the fuse does still blow = bad sign for the fuse-relay panel itself). If you do get a good result, unplug the C1, C8, and C9 connectors and the cigarette lighter, then reconnect the k connector and note whether the fuse blows or not. If not, reconnect the C1, C8, C9 connectors and the cigarette lighter one at a time until the fuse blows = that will help narrow down where the trouble is.

    No external running lights (no +12V on yellow wire with stalk knob rotated "on") -- Do the lights in the gauges still work even thought the external running lights don't work?
     
  3. wintech

    wintech Karting

    Jun 1, 2011
    206
    Perth WA
    Full Name:
    Pete K
    Thanks Steve,
    will check that shortly on fuse#2
    Correct on the stalk to park light position; headlights work as normal when on! will check the gauges same time as #2
     
  4. wintech

    wintech Karting

    Jun 1, 2011
    206
    Perth WA
    Full Name:
    Pete K
    Hi Steve,
    disconnected C4,C5,C6,C7 Noticed C8 had the Pink/Blk terminals very over heated so I moved them to a a spare slot on the plug.....my overhead, map and door lites now work!!
    I put a fuse into #2 and checked the male pin on K was 12v
    C4 12V on Voiletwhite,Red/green > replugged and fuse ok
    C5 12V on Red/black > replugged and fuse blew
    C6 12v on Red(1.5) > replugged and fuse ok
    C7 12v on nil. > replugged and no change

    As regards the lights being on 'park' and the dash lights on...nup! It is dead, however; introducing a 12v into the 'yellow' curcuit on the fuse board, yes the dash and all the park lights are on.
    Finding this a tad frustrating at this time.

    BTW, I removed the Red/blck wire from the K connector and no fuse shorting out. I could not access the lighter to remove the wires... quite a challenge gaining access!

    cheers
    Pete K.
     
  5. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,639
    Texas
    Full Name:
    Steve Magnusson
    Not the connectors that I had suggested investigating, but still very good information ;) If fuse #2 blows only when C5 is plugged back in = strong sign that the trouble is at the cigarette lighter. You may eventually need to get to the wiring of the cigarette lighter socket, but the easy first thing to try is just removing the removable cigarette lighter heating element from the cigarette lighter socket and see if fuse #2 still blows when reconnecting C5. Again, the wiring at the cigarette lighter socket is a common place where electrical modifications are added/made, and/or it's possible something in the central tunnel is shorting the terminals together. (PS Your door and map lights working with C5 unplugged is a good sign for those areas so you won't need to do anything there)

    If fuses 13, 14, and 15 are all intact, my suspicion would fall on the operation of relay O (it's the oddball ...006 relay with the "K" on the outer case). You'll need an assistant, but when you rotate the stalk knob to "on" = you should feel this relay "click" on by touching the outer case. If it doesn't "click", as a test, you can substitute one of the ...113 relays for relay O and see if it clicks on or not when when you rotate the stalk knob:

    A. If the parking and dash lights work when using a ...113 relay in the relay O position = buy a new ...006 relay for relay O use.

    B. If the ...113 relay also doesn't click when rotating the stalk knob to "on" = bad sign for the stalk knob switch itself.

    Try some of that and report back, and we'll go from there (e.g., if B, doing some tests to determine if it's a bad stalk knob switch or some other connection issue).
     
  6. wintech

    wintech Karting

    Jun 1, 2011
    206
    Perth WA
    Full Name:
    Pete K
    Thanks Steve,
    will get right onto it when I get back from work in a few days. I have already tried a different relay in the socket..but not the 'click' test! All fuses are good apart from #2. Could not remove the lighter socket from the top of the console so I may have to remove the console itself to see what may be happening under there.
    The electric system has performed without issue since I have had the car (other than the fuel pump issues; being the footwell earth cluster loose) The stalk knob is an outside possibility, however cannot be factored out. I am more biased toward it finally being a a DOH!!! moment of the Homer Simpson kind.
    Appreciate yr help as always Steve; kinds regards

    Pete K.
     
  7. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,639
    Texas
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    Steve Magnusson
    Yes, getting to the wiring of the cigarette lighter socket takes some work/disassembly, but, first, try just removing the cigarette lighter heating element for the cigarette lighter socket - that's easy to do ;)
     
  8. wintech

    wintech Karting

    Jun 1, 2011
    206
    Perth WA
    Full Name:
    Pete K
    Hi Steve,
    finally got back onto it! Relay 'O' ticks without any problems. The cigarette heating element was always out of the socket. Unplugged the rear defroster, and still blowing fuses. but it is definitely located in C5! ( I reversed up and disconnected the C1, C8 and C9 connectors, fuse good)

    On the running lights issue, the dash is not lit when no lights on. I noticed the tail, number plate and side markers lit up while to and fro-ing and thought I may have put a power wire into the curcuit and not removed it....but dash was lit. Binnacle was on park, turned it off, back on..nothing. Gently persevered on and off and it intermittently switches( dash and lights both) so am looking at taking the wheel off to allow the shroud to come off. This has never done this anytime in the 8yrs I have had the car, maybe a simple issue maybe not; we shall see.

    As per the C5 connector; are there any further tests or suggestions you feel are worthwhile to get Fuse #2 back in service?

    Cheers,
    a much more encouraged Pete K.
     
  9. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,639
    Texas
    Full Name:
    Steve Magnusson
    If you mean the cigarette heat element is always missing -- which allows junk to fall in the socket = not so good. If so, have a look inside the socket for something foreign shorting the terminals together

    With regard to C5, if you don't mind the cigarette lighter not working (and anything else added there that might be wired off it in the central tunnel), you can always remove the RN wire from C5 and plug the rest of it back together (and tape up the removed RN wire end). In the stock form, that RN wire in C5 only goes to the cigarette lighter.

    That sure seems like an intermittent stalk knob switch causing the trouble. If you touch a jumper wire from ground (or the neg battery terminal) to the V (green) wire terminal in the x connector and the running and dash lights always come "on" with the jumper in place, but are intermittent when using the stalk knob = bad sign for the stalk knob.
    Removing the steering wheel and shroud really won't show you anything - the switch assembly is under the hub, but even removing that (which ain't easy) probably won't help. There are many threads on how to disassemble the stalk knob to look at the switch components -- the biggest hint being to put a baggie around it when disassembling to catch the ball and spring if/when they pop out.
     
  10. wintech

    wintech Karting

    Jun 1, 2011
    206
    Perth WA
    Full Name:
    Pete K
    Hi Steve,
    good input re the RN wire in K block! The lighter element has always been in situ, but never used so no sad loss. I will isolate that socket connection.
    I will do a search on the stalk knob thread('s'... (considering the plural description; that is ominous in itself)
     
  11. wintech

    wintech Karting

    Jun 1, 2011
    206
    Perth WA
    Full Name:
    Pete K
    Final result!
    removed the steering wheel and hub covers. Took the retaining screws off the light binnacle, turned it to 'park' and the lights came on. I then spent a couple of hrs(with breaks) operating the stalk, while static and while manipulating the wire loom. on/off 100+ times and never missed a beat.
    An upshot of this exercise was that the P. side belt began working (although that was short lived) reverted back to cycling when all buttoned back up.
    The RN wire in the K plug was put back in position, but I placed a piece of shrink tube over the peg for no contact.
    All of the running lights now operate without fault, I feel that the loom from the binnacle was a bit tight and possibly the contact was lost through the connector.
    This has been an interesting exercise; yet I will be monitoring it for any recurrence.
    Cheers
    Pete K.
     
  12. turbo-joe

    turbo-joe F1 Veteran
    Silver Subscribed

    Apr 6, 2008
    5,660
    southwest germany
    Full Name:
    romano schwabel
    nice christmas gift you made yourself - all works again :)
     

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