Club 80-90 Forums

Having done it, I would say you're looking at an extra hour (at most) to do the lot. Its a simpler solution but the plastic used for the membrane has a finite life and all original ones are by now brittle - this is why the connection end breaks up. Bulb connectors eventually fail to make contact, and you get dry joints on resistors. If it works for you (and not knockling the thinking behind it) then great but from experience, the membrane can start to fail in more than one spot so you may well find you have to visit the job again.

My point is that whilst the full re-wiring of the dash is probably the best way to go, I've shown that there's an alternative method which is much less complicated and can work just as well.
There are probably many out there who don't want to do a complete re-wire, or can't because of limited technical expertise, and whilst I agree that my method may not be as permanent as a complete re-wire, it solves the problem of the worn out copper connections at the main block which is undoubtably the cause of the vast majority of issues.

I did get that and I had considered going that route with mine. I just chose to do the lot, fit a bigger connector and be done with it.

Heres a a way to fix broken bits of the dash pod. Wouldn't want the guy anywhere near me though.

https://www.youtube.com/watch?v=Hk1cojemglE" onclick="window.open(this.href);return false;

Shhh, don't mention your exhaust is hanging off or he'll be out with his glue.

Going to attempt to rewire my dash pod... just off to Maplin to get some veroboard...

How did you attach wires to the illumination bulbs? The old plastic membrane provides the connection for them, so when you took away the membrane, how is the electrical connection made?

LEDs, hotglue

https://club8090.co.uk/wiki/VW ... _connector" onclick="window.open(this.href);return false;

I rewired mine last weekend. Did the main board then made a small Pcb board that fitted into the plug end. For the dash lights I used 3 small 50mm section of led tape that I fed into the existing slots, worked a treat.

Great thread and pretty easy to follow.

So what kind of leds should I use for the three illumination ones?
12v leds? Would they still be dimmable?

Yes they do dim yes, although not in a linear fashion but doubt you'll notice. 12v LED yes, although they're just ordinary LEDs with a resistor. You can use any LED pretty much providing you use the correct value resistor but prob easiest to buy one thats set up for 12v. Maplins do them. As does ebay ofcourse.

Just attempting to recreate this but I think I've managed to blow up the leds by accidentally applying a full 12 volts directly to the led legs! Off to Maplin now to see if they have any in stock.

I'm very confused as to the layout for the battery/alternator light. Can anyone describe it to me?
As far as I can see, when you turn the ignition on, it provides +12 volts which goes through the 470ohm resistor, then the led and then back through the 150ohm resistor to the same positive +12 volt ingition. Surely it has to go to ground somewhere or the led wouldn't light? Thoroughly confused! Also not sure which way round the leds should be positionned (i.e. positive and negative legs)

MidLifeCrisis wrote:

Think voltage difference rather than positive and earth. Say plus 10v one side and plus 8v the other, voltage difference is 2v and hey presto led lights. Does that make it any clearer?

The way I see that diagram, boatbuilder is right, there is no voltage across the "Bat" led

Also, is there a 22 Ohm resistor from the 10 Volt reg to earth on the original? There may be, but it's not usual practice with a simple 3 leg V reg.

The longer leg on an LED is +ve. Some LEDs have a flat bit on the edge of the plastic, which indicates the leg on that side is -ve

Oh, and what is "SP1" ?

The 12v from IGN goes through the 150ohm resistor to the diode then on to the ALT connection; Then in addition to that 12v from IGN goes through the 470ohm resistor, through the LED then to the diode and then on to the ALT connection.

I was told this was so that if the LED failed the alternator would still get a 12v signal through the 150ohm resistor (and perhaps also to limit the current running through that LED).

The pic may also be confusing you - the LEDs are connected to the two PCBS tracks they pass over not the two either side of the resistor (the LED symbol in that pic is a little confusing in this respect)

Hope that helps?

SP1 is spare (or glow plug light on diesels)

Makes a bit more sense now. So when the ignition is switched on current flows through the 470ohm, then led, then diode to alt. Alt acts as a ground I presume in that case.

Then when the engine is running and the alternator is generating power, it pushes back current in the opposite direction which is stopped by the diode and hence the led goes out.
I've read somewhere that alternators sometimes have an exciter connection so maybe the alternator needs a voltage applied in order to start it up. If it just relied on the voltage after the led, the 2v might not be enough to excite the alternator so that could be another reason for the 150 ohm bypass...It would provide a higher voltage to the alt.
Not saying I'm right about all of that, just thinking out loud!

Anyone know where to get those 2.54mm pitch terminal blocks? Don't fancy waiting a month for them to come from China!