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Volkswagen Jetta, Golf, GTI: 1993-1999, Cabrio 1995-2002 (A3) vr6 golf gen3 speedometer and tachometer not working


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Last Post: Nov 24, 2016 1:23 PM Last Post By: JBGLX
BobD

Posts: 1,844
Registered: 11/29/04
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Dec 29, 2006 2:38 PM   in response to: bguser in response to: bguser
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Right at the sensor you'll find the 3 wires.
The outer two are power, +12v & GND.

The center pin is the pulsing signal.
I believe you can do the following.

A. Unscrew the sensor from the tranny, leave the harness connected.
B. Connect the multimeter to the battery ground, and the center wire at the sensor.
C. Turn the key to ON
D. Spin the shaft/dial you see in the bottom of the sensor.

You should see the mutli-meter jump around as you turn the sensor.
Now there is one reason why this may not work.
If there is something wrong in the cluster, then the signal may get pulled low.

So the best way to test the sensor is to remove it from the car and test it with an isolated 12V supply.

BobD
kiloman

Posts: 6
Registered: 08/27/06
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Dec 30, 2006 1:12 PM   in response to: flex in response to: flex
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Hello from Dublin,Ireland.

I have a 2000 Golf Cabriolet with strange speedometer problems.

The first is that no matter how full or empty the fuel tank is the gauage always reads half. It does not move, only from resting to half on start-up.

The second issue is that my MFA reads constant 99.9mpg(great except I do have to fill the tanks more often than that!!!)

Are these problems consistent with a bad earth or bad cluster?

Thanks in advance for any help.
BobD

Posts: 1,844
Registered: 11/29/04
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Dec 30, 2006 1:32 PM   in response to: kiloman in response to: kiloman
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The 99.9mpg is a dream.....
But the 99.9 is related to the fuel gauge always reading Mid.

My guess, your float in the gas tank is stuck.

If you unplug the connector that goes to the tank, and turn the key ON, you should see the fuel needle drop. If you don't, then the issue could be in the cluster.

I would measure the resistance from the float (@ connector) to vehicle ground. Then measure it when different amounts of fuel are in the tank, for example right after a fill up.

With a POT you could adjust the fuel signal to the cluster and watch the needle move around.
I believe the fuel resistance range is from 10ohm to about 55ohm. I can check and repost later if you wish?

BobD
kiloman

Posts: 6
Registered: 08/27/06
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Dec 30, 2006 1:45 PM   in response to: BobD in response to: BobD
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Hi,
Thanks for the prompt reply.

I disconnected the connector yesterday and the needle dropped. I got a mechanic chap to "jump" the gauge to read full but it still read only half.

The range would be great as I can then give them to the mechanic and see if he can force correct values into the unit.

Previously another mechanic removed the float and the guage read only 2/3 full when it was in the full position.
BobD

Posts: 1,844
Registered: 11/29/04
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Dec 30, 2006 5:16 PM   in response to: kiloman in response to: kiloman
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Kiloman,
What do you mean " "jump" the gauge to read full".

The feedback wire to the cluster is not a voltage. The float is a resistive load, so current must flow from the cluster to the float.
The maximum induced voltage at the float is just under 2.0V.

Also, the signal is proportionally inverted.
Fuel level goes up.....resistance goes down.

Here are some numbers I have:
1/4 Tank 150 ohm.
1/2 Tank 95 ohm.
3/4 Tank 68 ohm.
Full Tank 45 ohm.

With the connector open, measure the resistance to ground.
I would guess you should be measuring something in the 95 ohms.

Good luck,

Post back what you find!!

BobD
kiloman

Posts: 6
Registered: 08/27/06
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Dec 30, 2006 5:57 PM   in response to: BobD in response to: BobD
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Hi BobD,
I will check this out and also find out how he jumped the unit. I think he connected two pins together, dunno.

But when a mechanic removed the float unit he move the float throught the full range of its movement, the max it got to was 2/3. Anyway I really appreciate the help as my local garage just wanted to junk the cluster and charge me a lot of money to sort it out.

Thanks again.
bguser

Posts: 2
Registered: 12/29/06
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Dec 30, 2006 7:06 PM   in response to: BobD in response to: BobD
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Bob: Thank you for the great idea.
You are a big help!
kiloman

Posts: 6
Registered: 08/27/06
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Jan 9, 2007 5:10 PM   in response to: flex in response to: flex
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Hi BobD,
I got the sender looked at and am no further along than previously.
I earthed the sender unit and got 80ohms.

A full tank of petrol(gas) reads just at the first marker after half.Even with the float out of the tank and in the full position the gauage reads the this level.

So is it the instrument cluster?

Thanks for your help
BobD

Posts: 1,844
Registered: 11/29/04
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Jan 9, 2007 11:01 PM   in response to: kiloman in response to: kiloman
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Kiloman,
I believe it could still be the float.
If you look at the resistance values I have listed above you will see that the 80 ohms you were reading falls just above a 1/2 reading.

Inside the float there is a variable resistor that changes as the mechanical arms moves.
Were you able to measure the resistance of the float while moving the arm around?
The float is across pins 2 & 3 of the connector.

If you want to try one last thing.....you can try this.
1. Buy some resistors.....close to the values listed above.
2. Turn the key "ON", and place the different value resistors across pins 2&3 inside the harness side at the fuel tank.

If you have any questions at all, let me know.

And, if you weren't so far away I would send you some resistors.

BobD

kiloman

Posts: 6
Registered: 08/27/06
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Jan 10, 2007 7:30 AM   in response to: BobD in response to: BobD
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Hi BobD,
Thanks again for the response.

Description was never one of my strenghts.

Last night my mechanic removed the float unit and tested the resistance at different tank levels. We also inputted different resistance values into the plug running back to the dash.

The highest tank level(full tank) read about was 20 (can`t remember fully) and the lowest was about 360 again recollection is bad.

We were about to stimulate the movement of the gauge but not above this first mark after half way.

As there is a sizable span of readings the float I can assume is ok.

The float has free movement in the tank and is orientated correctly.

I filled the tank and disconnected the battery to see it that would "reset" the gauge.

Therefore can I assume that the problem lies between the tank and the dash or the dash itself. If it was in the dash what would need to be done to rectify this?

Thanks
BobD

Posts: 1,844
Registered: 11/29/04
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Jan 10, 2007 8:27 AM   in response to: kiloman in response to: kiloman
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Attachment fuel-gauge.JPG (40.5 KB)
Kiloman,
So you did get to measure resistance while moving the float around. Good.
I miss understood what you said about the 80-ohms....

Well, I guess it sounds like the issue may be in the cluster. The circuitry inside the cluster for the fuel gauge is so simple. I've never had a repair that was only fuel guage related.

I would probably open up the cluster and have a look around.
I would want to make sure the fuel needle has full swing.
One thing not to do would be soldering. Unless you see something specific, I would not touch up solder joints with an iron. This can prove to cause problems down the road.

Are you able to get your hands on another cluster?

If you have a couple of spare hours on a Saturday, I could give you a new stepper for the fuel gauge. I have plenty of them....becuase the've never failed for me.
There is no soldering required for the fuel gauge motor.
Unlike the speedo & tach, the fuel gauge just pops in place.
Should take less than an hour to switch out....

BobD
kiloman

Posts: 6
Registered: 08/27/06
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Jan 10, 2007 9:32 AM   in response to: BobD in response to: BobD
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Hi BobD,
I am looking for another cluster to see if it is just my gauge.

Funny that you mention that it is rare that just the fuel gauge to go on its own. Apart from the MFA being a not displaying the correct MPG(99.9) the car does not redline. It reaches 5200rpm and the limiter kicks in. The cluster redline is at 6200rpm I think.

I may take you up on the offer of a fuel stepper if it is that easy an install. I will mail you offline to organise payment and delivery. If you could supply the installation instructions that would be great.

Again thanks for your help.
BobD

Posts: 1,844
Registered: 11/29/04
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Jan 10, 2007 11:51 AM   in response to: kiloman in response to: kiloman
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kiloman,
You can email me at a3clusters(a)hotmail.com

When I get home, I will have to go through my notes on MFA clusters. The thing that bugs me is this, if the stepper has something wrong with it, then yes the needle may display wrong.

But why is the MFA still displaying 99.9mpg.
It depends on how the circuit is layed out.

I wish you weren't so far away.....I could send you a loaner cluster....
Your issue is a doozy!

BobD
Mike B.

Posts: 1
Registered: 02/07/07
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Feb 7, 2007 1:11 PM   in response to: BobD in response to: BobD
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I have this exact same problem w/ my '95 jetta GL III 4 cyl. Do you know approximately how much it costs to fix/replace the cluster at a shop?
BobD

Posts: 1,844
Registered: 11/29/04
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Feb 7, 2007 5:59 PM   in response to: Mike B. in response to: Mike B.
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Mike B.
You can send me an email at a3cluster(a)hotmail.com
fb

Posts: 1
Registered: 06/13/07
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Jun 13, 2007 9:34 AM   in response to: BobD in response to: BobD
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How do I contact BobD about repairing a cabrio cluster with a bad speedometer stepper motor
Dan Reed

Posts: 1,462
Registered: 05/19/04
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Jun 13, 2007 10:15 AM   in response to: fb in response to: fb
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have not seen him here in a while. Hope he's ok.

a3clusters (at )hotmail.com
BobD

Posts: 1,844
Registered: 11/29/04
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Jun 14, 2007 12:23 AM   in response to: Dan Reed in response to: Dan Reed
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Hey...I was sleeping. JK..
Sorry, it's summer time.....so I spend more time outside.
poppinfresh

Posts: 1
Registered: 06/22/07
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Jun 22, 2007 1:54 PM   in response to: flex in response to: flex
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I have a 97 jetta gls with 88000 miles that im thinking of purchasing. I drove it two times. the first time the gauges all worked fine. but then a few days later the speedo and tach were not functioning. I asked the guy if he could get it fixed. He ended up fixing the cluster by replacing it with a used one. I didnt however notice if the odometer was working with the broken speedo and tach. It seems like everyone here has a problem like this on and off. i was just wondering if the odometer normally doesnt work when this occurs, or if the speedo and tach are related to how the odometer works. i just dont want the milage to be off.
thanks!
BobD

Posts: 1,844
Registered: 11/29/04
Re: vr6 golf gen3 speedometer and tachometer not working
Posted: Jun 25, 2007 6:11 PM   in response to: poppinfresh in response to: poppinfresh
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With this type of cluster fault, the odometer should be adding up. :)

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