LagondaNet

[peacorp]

My side lights stopped working on my S2 and of course all the other lights with them. So in time honored fashion I put on my fault finding hat and did the following.

1: Tested the side light latching relay [27a] by removing the coil wires and applying 12v directly to the coil, the relay switched the side lights on. So the relay is ok.
2: Removed the panel under steering wheel to give access to the wiring for the binical.
3: Tested the operation of the side light switch, which is attached to the smaller ribbon cable.
Note: do this with the power off and with a multi meter set to Ohms. Trial and error will lead you to the correct switch. I have recently replaced both sets of touch button pads so I already know which wire is which but the test is simple as there is a common and a wire to each button for the lights and 2 separate wires for each of the other buttons. However the button tested ok.
4: The problem must be in the white plastic box that the ribbon cables go into, the binical interface box which is not shown on any of my drawings.
5: Phone around for a price of a replacement box before I open it and expose the contents to air for the first time in thirty years and was quoted from £150 to £900.
What's in the box I hear you ask?, a miniaturised super computer with gold plated connections insulated with Muir....... So I drill out the small rivets and open the box................inside are none of the afore mentioned wizardry, but disappointingly 1 small circuit board with 11 resistors 11 zena diodes and 11 transistors connected to 3 ribbon cables total cost less than £15 on the plus side its easy to repair.
6: I tested the zena diodes and found one to be closed circuit which is not correct, so I assume the corresponding transistor is damaged as these are slightly more difficult to test and in this case simple to replace.
7: Visit Maplins or Radio Shack, as the 2N1711 transistor is discontinued get a 2N3053 £0.98 and a BZV85C Zena Diode £0.34.
8: Disconnect the board from its wiring, although you don't have to but its easier to solder on a bench.
9: Remove both the zena diode and transistor and install the new ones checking to ensure they are fitted the correct way round on the board.
10: Refit unit and test. All my lights now work fine (I like to think they are better).

Final Note: this box is a basic interface between the touch buttons and the latching relays as the touch buttons would not last long switching the current required by the latching relays. There are only 11 transistors because there are only 11 relays to switch the other touch buttons operate dash items which are low current e.g. the clock.

I hope you find this useful.

[Vrije]

Yes simple as that.
My lights on 13059 died this winter so I brought the white box to my
local electronics shop (former Tandy) got it back with all new fittings in it.
Total cost icl. labour 30 euro.

Box of 13007 was also done before as a test case wich set me back 20 euro.

Harry

[Vrije]

P S,
don't just get an other interface box if you don't like this fiddling around.
Box of 13007 is different to 13057 wich in term is different to 13059

One has 10 circuits one has 11 (yep) , all use different cabling / connectors.

Yes sir, these machines are called Lagondas.

Harry

[Lagondanet]

All very interesting. Thanks for sharing your knowledge on the subject.

[peacorp]

[Tim_C]

I've lost mt interior lights/cigar lighter curcuit and also, after transportation, the left turm indicatoor. Right is fime as are the hazzards
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