Does anyone have a photo of the inside of a 251941531L headlamp switch (nine terminals on the back). Mine had jammed onto sidelights, it turned out something had melted a bit, I've managed to clean it up and file most of it back into shape. But I can't quite work out what it should look like!
N.B. Please don't take a working one to bits for this - they are incredibly fiddly to get back together again!
Failing that does anyone know where I can get a new one - the JK one only has eight terminals on the back, and it is obselete at VW. Failing that does anyone know if a 251941531M (non dim-dip) will fit without blowing anything up at the headlights?
The wiki article about fitting the headlamp relay upgrade mentions the dim dip & to disconnect the rsistor if you have it fitted. This implies to me that the extra connector on your switch is the power to that circuitry, so if you disconnect the dim dip resistor and don't use it you should be ok with an 8 teminal switch. I could be completely wrong of course, but you've got me intersted now
naughty word comes to mind as I recently re-assembled one but the sliding contacts have a particular shape that only fits one way in the recesses with the dimples facing upwards. If you look at the top half of the switch you will suss how they slide across to make contact with the terminals. As long as you haven't lost the tiny ball bearing that sits on top of the spring (which provides the rocker mechanism) you should be ok. Re-assemble the switch with the rocker in the mid position and don't foreget to fit the springs behind the contacts.....use the best end of the springs behind the contacts and stretch them a tad if they have shortened with age. A lot of folks on here have disconnected the dim dip resistor and done away with it altogether (me too!) so you may find that a standard one will work but no dim dip function. I have no schematic for your particular switch/lighting circuit so can't say whether an alternative unit will work.
Thanks for the replies - I managed to get it back together and sitting in the three positions nicely, but there was a once-molten blob of plastic on the contacts plate. I think this used to be a certain shape to push the single-spring loaded contact up in the air, away from contacts in one position or something? But I can't be sure - anyway upon reassembly so far I have got 'off' and 'sidelights' but no headlights!
The switch contacts usually slide along the horozontal plane and rely on spring pressure from the rear to make good contact with the various terminals. Did you clean the switch contacts/terminals before re-assembly? Also, if it overheated then the top half of the assembly may have 'bellied' outwards but you would normally see that. What year/model is your van?
Yes - cleaned things up, it looks as if there was some kind of bit of plastic that was sticking up and helping to guide the 'sliding contact holder' along. It is this that I'm not sure of the shape of as it was melted, due to dirty contacts getting hot I think. Van was registered 90/91, so probably made 89/90 which is in the dim-dip timeframe I think.
I have only seen the 8 and 7 terminal switches and the 8 terminal type is fitted to dim dip models so a bit mystified why the change to a 9 terminal as I cannot see what the extra lead could be used for. You need to identify the colour codes and the terminal numbers on the back of your switch and cross reference to schematics of vans built between '87 ( 8 terminals) and '90 ( 9 terminals). I would adapt/modify the wiring at the switch to work with the more easily available 8 terminal switch. A lot of the terminals are in parallel to reduce the current flowing though the contacts but you need the schematic for your model before you can attempt any changes.
Just an update - I've got it fixed now, took it to bits again and filed the bit of plastic on the contact plate off completely, doesn't need a slide-guide as there is not much room for it to move anyway. Filed everything, cleaned and it works again.
I reckon anyone could mend their switch with a bit of patience, and some small files! For the record these are the terminals and connections for switch positions (1/2/3 - 1 off, 2 sidlights, 3 headlights)
X - ignition
56 - headlights (connects to X for position 3)
56D - dimmed headlights (connects to X for position 2)
30 - battery
30 - battery
(all below connect to 30 for positions 2 and 3)
58 - numberplate light /fog light feed
58R - right side and tail lights
58L - left side and tail lights
58b - dash lights feed
