Dash dial lights will not turn on

Hi all,

My dash lights for the speedo, rev counter and clock will not turn on, my vdo's do though, which leads me to believe it is the dash unit itself
I have removed the fascia and changed the bulbs but to no avail.

Any ideas?

thanks

Make sure that your Brightness adjust is allowing the consoles to go dim to bright.

Then turn it full bright and measure the voltage on the grey/blue wire in to the cluster.  You should see a varying voltage as you turn the dial.  If not then it is a connection issue on the switch or a broken wire from the switch to the cluster.

If you have the proper voltage to the cluster then check the Voltages at the bulbs.  Those guys have been known to me not to fully seat in the holder and as you twist them there is a false lock, so they may not be making contact with the mylar.  Measure the bulbs for 12V and Ground, if you don't have it on the outside of the bulb then Check the input side of the connector, and possibly twist the bulb a wee bit more.  If they still don't work, then you can run a wire from the connection side, and flatten the wire and put it on the Positive side of the bulb.  Be very careful about finding the 12V side of the bulbs….. On early Dubs the cluster lights weren't fused to well an tended to Burn the wires.

One side of the bulb is ground or 0 resistance to the Brown wire.  The other side is 0 resistance to the Black.

I know that I had to twist my bulbs in a tad further, but I was using the newer style sockets, with removable bulbs that were 3 watt vs 1.

(Took the bulb holders out of a Isuzu, Toyota, Honda, or Saturn at the breakers, then sourced the "Warming Lamps" for the car I took them out of as they are Higher Wattage Bulbs.).

Briano1234 said

Make sure that your Brightness adjust is allowing the consoles to go dim to bright.

Then turn it full bright and measure the voltage on the grey/blue wire in to the cluster.  You should see a varying voltage as you turn the dial.  If not then it is a connection issue on the switch or a broken wire from the switch to the cluster.

If you have the proper voltage to the cluster then check the Voltages at the bulbs.  Those guys have been known to me not to fully seat in the holder and as you twist them there is a false lock, so they may not be making contact with the mylar.  Measure the bulbs for 12V and Ground, if you don't have it on the outside of the bulb then Check the input side of the connector, and possibly twist the bulb a wee bit more.  If they still don't work, then you can run a wire from the connection side, and flatten the wire and put it on the Positive side of the bulb.  Be very careful about finding the 12V side of the bulbs….. On early Dubs the cluster lights weren't fused to well an tended to Burn the wires.

One side of the bulb is ground or 0 resistance to the Brown wire.  The other side is 0 resistance to the Black.

I know that I had to twist my bulbs in a tad further, but I was using the newer style sockets, with removable bulbs that were 3 watt vs 1.

(Took the bulb holders out of a Isuzu, Toyota, Honda, or Saturn at the breakers, then sourced the "Warming Lamps" for the car I took them out of as they are Higher Wattage Bulbs.).

Cheers mate

Tested voltage at dial, is 1.8v at max, 1.4v at it's lowest, that means at the bulb I get 1.2-1.6v when I tested. I assume this is 10v too low, any ideas?

Thanks

I would check your Fuses.
Use a Meter.

Make sure that you have a good ground for measurements,  It could mean your Switch is in that CCDD state.  But no 12 in would be the issue.

CCDD  ca-ca-doo-doo  

Briano1234 said

I would check your Fuses.
Use a Meter.

Make sure that you have a good ground for measurements,  It could mean your Switch is in that CCDD state.  But no 12 in would be the issue.

thanks

any idea what fuse it is?
I dont have any other electrical problem that i know of.

cheers

I used this diagram today to find a fuse, I think it's fuse three you want.


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ryan-witch said

any idea what fuse it is?
I dont have any other electrical problem that i know of.

cheers

Year and model would be nice to know.

www.cabby-info.com she has all the Cabriolet Fuse panels listed

Wes_france said

I used this diagram today to find a fuse, I think it's fuse three you want.


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Where was this diagram from! Helpful that!

Thanks

Briano1234 said

ryan-witch said

any idea what fuse it is?
I dont have any other electrical problem that i know of.

cheers

Year and model would be nice to know.

www.cabby-info.com she has all the Cabriolet Fuse panels listed

Its a 1986 gti cabby

ryan-witch said

Wes_france said

I used this diagram today to find a fuse, I think it's fuse three you want.


Sent from my iPhone using Tapatalk

Where was this diagram from! Helpful that!

Thanks

I can't take any credit I just googled mk1 golf gti fuse box and looked at images


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if its an 86 it may not have a fuse, i think it was around 88 the switch and wiring looms were modified to be fused.

check the plug on the light switch, if its red you have a fuse, its the same one as the number plate lights. if black, you probably dont have a fuse, check the grey/blue wire on the switch for power, and chase it in the loom looking for meltyness

rubjonny said

if its an 86 it may not have a fuse, i think it was around 88 the switch and wiring looms were modified to be fused.

check the plug on the light switch, if its red you have a fuse, its the same one as the number plate lights. if black, you probably dont have a fuse, check the grey/blue wire on the switch for power, and chase it in the loom looking for meltyness

I believe it not to have a fuse
I think it may be the switch itself
It gets 12v in, and at the coil inside the switch it also has 12v, but i can just access the prong from the dimmer dial that plugs into the relay bit which in turn goes to the grey blue cable.
I get basically nothing, 2v with some wiggling
i did have the mfa light come on yesterday for 5 mins before i lost the magic switch position

sounds like the dimmer is at fault then, you could run a wire between the grey/green and grey/blue for now that will bring them on full with the plate lights

rubjonny said

sounds like the dimmer is at fault then, you could run a wire between the grey/green and grey/blue for now that will bring them on full with the plate lights

Is there any other way to test the dimmer with a multimeter?

i'll just buy a new switch if its at fault, only £10 on ebay

if you see 12v in, you should see 0-12v out as you play with the dial when testing with a multimeter. if you dont, then yep its faulty

if you open the switch you might find its an easy fix, there is a V shaped prong on the wheel which needs to touch the top and bottom of the dimmer mech, might just need a clean/bend.

at 'full' the prongs are just shorted between the input and output pins so you could solder in some wire or similar to do the same. the lower voltage settings are run up and down a coiled wire section, if theres a break in the coiled wire that would stop the dimmer section working

as it happens my mk2 has a 'sweet spot as well at full, need to fiddle then leave it be else the dash lights go out

rubjonny said

if you see 12v in, you should see 0-12v out as you play with the dial when testing with a multimeter. if you dont, then yep its faulty

if you open the switch you might find its an easy fix, there is a V shaped prong on the wheel which needs to touch the top and bottom of the dimmer mech, might just need a clean/bend.

at 'full' the prongs are just shorted between the input and output pins so you could solder in some wire or similar to do the same. the lower voltage settings are run up and down a coiled wire section, if theres a break in the coiled wire that would stop the dimmer section working

as it happens my mk2 has a 'sweet spot as well at full, need to fiddle then leave it be else the dash lights go out

I shall remove said devil switch and try the above (may need some assistance with pictures)

Many thanks for your help though!!!!

ryan-witch said

I shall remove said devil switch and try the above (may need some assistance with pictures)

Many thanks for your help though!!!!

Not a Devil Switch, not getting to the Ignition switch on my 90's is a Devil of a job for all that has to happen on a "Air-Bagged" Electric window car.

As Rub said, the dimmer part since it rotates, can be dirty, worn out, or bent.

The roller moves a wiper arm over a resistive wire.
As you are moving the roller from Dim to bright you are decreasing the resistance of the wire.  When the dimmer is full bright, there is 0 resistance between the wiper arm, and the 12V input.

You can use a Ohm Meter (Switch out of the car) and see if the resistance varies as you move the dial.

You can measure the input voltage 12, then measure the output as you roll the dial… it should go from 2V to 12.

If you measure the resistance between the low end and the high end, you will see it is about 20,000 ohms low and 0 high  if it is infinite, then you may have a open wire.

85-88 Cabbies the lamps were on pin 58-58b with 58b being the input or 12V side. So with the dimmer dial rolled to the input pin there is 0 resistance.

Update,

Removed the switch, took apart and pushed the prong down to rub against the coil. The dimmer dial now has friction.
Plugged in! Hey presto, let there be light!!!

However the lights don't stay on when I put the clocks back

PS: you're all legends :p

The lights in the "Clocks" or instrument pod?
Or
All the lights in the DASH as in heater and switches?

If it is just the "clocks/instrument" pod, then plump your connector using a piece of tape under the Mylar on the pin side of the plastic tongue, and tap an additional Ground to the pin side of the connector pin 2 brown to frame.