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samjc

Mk2 Polo Instrument Cluster Fault

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samjc

Hey there,

I'm hoping some of you may be able to help with the instrument cluster issue I've got or possibly point me in the direction of a similar thread that might answer my question.

I've got a fault with the instrument cluster on my VW Polo Mk2. The Speedometer works and the clock works (no rev counter). The temp gauge, Fuel gauge, indicator LED, Battery LED, Oil LED & handbrake LED do not work, however the full beam LED does work. I've tested the sockets that plug into the cluster at the bottom and am receiving 12V DC from the appropriate controls (i.e. handbrake on 12V handbrake off 0V) which I think means the fault is the instrument cluster. Not sure wether the LEDs are gone, but then I don't understand why the Temp Gauge and Fuel Gauge wouldn't be working.

The arrangement of the cluster is Speedo on the left. Temp Gauge top middle, LED cluster centre, Fuel Gauge bottom middle and clock on the right.

Many thanks in advance

post-921402-0-13973900-1439324271_thumb.

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nige8021

First Welcome to the forum.

The fuel & temp gauge not working could be the voltage stabiliser unit in the speedo unit failed, have you got 12v on pin 14 of the speedo connector with the ignition ON?

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samjc

Morning Nige8021, thank you very much for your response. I believe I did have 12V at pin 14 with the ignition on, from the scheme I believe pin 14 is my common so I left one test probe in pin 14 while I tried the other appropriate pins with controls.

The voltage stabiliser, I'm thinking its possibly a part I can take off an old (working instrument cluster) and get the soldering iron out?

Many thanks again for your input it's greatly appreciated.

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samjc

Looking more into it today, I found a link to these two voltage stabiliser. When I removed the instrument cluster yesterday evening I remember seeing this kind of 3pin chip mounted on the rear above the speedo

http://uk.mouser.com/Search/ProductDetail.aspx?R=LM7810ACTvirtualkey51210000virtualkey512-LM7810ACT

http://uk.mouser.com/Search/ProductDetail.aspx?R=LM7810CTvirtualkey51210000virtualkey512-LM7810CT

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nige8021

Here's the VW part number 171919803 voltage regulator

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samjc

Thank you for the part number. Do you think this could possibly solve the LED issue too?

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nige8021

In the diagrams I have, the regulator is only there for the water & fuel gauges, the warning lights are in a module? so you might have an internal connections problem?

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samjc

Ok yeh so possibly faulty LEDs, looking at the back of it last night the legs look like they go straight onto the blue flexible plastic sort of PCB board, or at least the legs from the black plastic chassis which holds the LEDs, I'm hoping they are mounted in a way much like the voltage regulator which pulls out (after undoing the screw).

Many thanks for you help again, I've put a voltage regulator on order last night so I will keep you posted with how I get on.

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RobertTaylor

Hi, I'm having a similar problem. When I turn on my lights with the ignition on the high beam selection has reversed. The lights behind the clocks turn off and the dimmer function only dims the leds for the high beam/handbrake?

Any solutions or ideas would be welcome.

Mk2 1988 polo

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Maurice
On 11/08/2015 at 21:18, samjc said:

Hey there,

I'm hoping some of you may be able to help with the instrument cluster issue I've got or possibly point me in the direction of a similar thread that might answer my question.

I've got a fault with the instrument cluster on my VW Polo Mk2. The Speedometer works and the clock works (no rev counter). The temp gauge, Fuel gauge, indicator LED, Battery LED, Oil LED & handbrake LED do not work, however the full beam LED does work. I've tested the sockets that plug into the cluster at the bottom and am receiving 12V DC from the appropriate controls (i.e. handbrake on 12V handbrake off 0V) which I think means the fault is the instrument cluster. Not sure wether the LEDs are gone, but then I don't understand why the Temp Gauge and Fuel Gauge wouldn't be working.

The arrangement of the cluster is Speedo on the left. Temp Gauge top middle, LED cluster centre, Fuel Gauge bottom middle and clock on the right.

Many thanks in advance

post-921402-0-13973900-1439324271_thumb.

 

Hi All,

I have just fixed the exact same problem on a 1986 Formel E Polo. 

I did have 12v at pin 14 on the main cluster plug. (See 2nd or 3rd posts) If you follow the printed circuit track from that pin you will find it goes directly to the inside pin of the voltage regulator. There should be 12v at that pin. I had 0v. Examination showed a break in the pcb track which wasn't repairable so I soldered a bridgeing wire from the black wire that goes to terminal 14 to the leg of the voltage regulator. This has been a success!

I also put a bullet connector in the middle of the wire so that the instrument cluster isn't permanently soldered to it's connecting plug!

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Iain MacKay

Hi Maurice

 

I just had the same fault on my 1986 Formel E Polo, its been like that for 3-4 months. I followed your instructions and its now all working perfect.

I also read that if the dash has a fault and isn't sending a signal back to the alternator it won't charge the battery. Not sure if this is true but I kept mine topped up.

Thanks 👍

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nige8021
1 hour ago, Iain MacKay said:

Hi Maurice

 

I just had the same fault on my 1986 Formel E Polo, its been like that for 3-4 months. I followed your instructions and its now all working perfect.

I also read that if the dash has a fault and isn't sending a signal back to the alternator it won't charge the battery. Not sure if this is true but I kept mine topped up.

Thanks 👍

 

First Welcome to the forum.

 

If the Alternator warning light has blown there will be no "excitation" voltage going to the alternator so it won't produce an output. An easy way to test the warning light is to remove the thin wire (normally blue) from the alternator and short it to ground/chassis then with the ignition on the warning light should be ON, if it is ? that has proved the warning light and the wiring to to alternator, so if it doesn't come ON when the wire is re-connected the problem is in the alternator

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