Improving your Cluster Connections and ground.

briano1234 · Jun 17, 2011

How to improve your Speedometer connections:

Remove your Instrument cluster:
http://cabby-info.com/Files/DashRemoval.pdf

On the back of your cluster, remove the Shroud off the main connector
by pressing in the finger tabs, and carefully pry off.

Carefully lift the Mylar connector off the tongue.

Place one strip of electrical tape on the pad side of the plastic tongue.

Replace the shroud.

You should also remove the nuts off the back of the cluster and sand them to clean them.
Sand the lock washers too.

Brush the mylar with steel wool I usually twirl it around the stud sticking out, and that cleans the mylar too.

Replace the nuts and tighten them.

Now you are going to add an additional ground wire to the main cluster connection.

From the Large Connector, go back about 4 inches and use a wire splice to join
a 12 inch piece of wire to the number 2 pin, brown wire.

Between the "X" drill a small pilot hole, and sand around it to get it to bare metal.
Add a terminal connector to the bitter end of the new spliced wire.

Use a sheet metal screw to screw the connector to the frame. You now have a good cluster ground.

blackcoal · Mar 7, 2012

just wondering what does this help improve?

briano1234 · Mar 7, 2012

intermittent gauges.

tpndance · Jun 10, 2012

Would this help fix the issue with my RPM gauge going out with I turn on the head lights?

briano1234 · Jun 10, 2012

Possibly, as it only improves the gauges.

rrpwiii · Jul 10, 2012

I finally got irritated enough at having a sleepy instrument cluster to try this. Every thing in the cluster other than the high beam indicator and the speedo had been intermittent for about about a year and getting worse. So far so good, I had forgotten how much I like having a tach. Thank you for the instructions briano1234.

jesuswasabeatle · Jul 12, 2012

Followed the guide, and I did it. Very well written guide, almost German in it's precision.

Twocams · Sep 7, 2012

Well its possible to get the little shroud up side down....and harness plugged in. I dont know, not paying attention. Now the idiot lights dont work. Do I need a new stabilizer or circuit board?......or.

Rich

briano1234 · Sep 7, 2012

Yes. The pins on the connector have to go on top.

Twocams · Sep 7, 2012

Thanks briano,
It wasnt broke after all....didnt have the plug in all the way on one end. Fixed

Rich

DazedMikey · Sep 6, 2016

briano1234 said:
How to improve your Speedometer connections:

"From the Large Connector, go back about 4 inches and use a wire splice to join
a 12 inch piece of wire to the number 2 pin, brown wire."

By join do you mean to replace where the brown wire goes or add a second path for the brown wire?

briano1234 · Sep 7, 2016

Join, means splice, or add to. You splice in to the main ground for the cluster, and take that to frame ground behind the cluster.
I used a Scotch lock wire splice connector here.

Amsterdcub · Nov 21, 2020

I can't even tell you how excited I got when I found this post. The stupid tach and lights dying when I turned on my headlights have been driving me bananas for a year now. I tried the tape trick first with no result. When I get another free dry day I'm going to splice and add the new ground behind the instrument cluster. I already asked my garage to test my battery/ transmission/ engine grounds and all were solid. Thanks so much briano for taking the time to post these clear tips and instructions.

briano1234 · Nov 21, 2020

Lights as in cluster lamps, as that sounds like a bad ground to the cluster or mylar run, and or a 14V issue....
as pin1 should be for the lamp circuit...pin2 brown ground, and pin 14 is usually 12V in black.

It could be a flaky connection or mylar run, so test the voltage on the cluster at the 10V stabilizer. middle pin is ground, one pin is 10V the other battery.

Amsterdcub · Nov 21, 2020

Lights as in cluster lamps - having the exact same situation as described above in #6 - blue high beam indicator comes on, dash lamps off, tach off, but speedo working - all when I turn on the headlights. My reverse light also stopped working at the same time as all this but I haven't checked the bulb on that either. I'll check the connection as you stated and test the voltage before I splice and add the ground (maybe I don't need to!) Thanks!

briano1234 · Nov 22, 2020

Tach off electrical/connections. Speedo is Mechanical so nothing there. Reverse could be the lamps or the Switch on the tranny, Dash lamps could be burned out. so you may just need to re-tweek the connections and change the bulbs, that is if you have 0-10V on the Dash Bulbs when you twist the headlight switch. knowing the year helps as well as model number, as I have a Bentley on rabbit/golfs prior to USA making Westy's and there are separate Westy rabbit pages, as well as a haynes.

Amsterdcub · Nov 22, 2020

Thanks for this and for taking the time. My car is a German Cabriolet GLi from 1987. I've searched high and low for Haynes books for both this and my T3 camper but they are very difficult to find (in English in Europe).

briano1234 · Nov 22, 2020

1987 Cabriolets were all euro built, and the Bentley is a good guide as the Wiring Schematic are all in there.
The grounds for a 87 is different than my guide, which is for a 1990 ish digifant.

For an 87 look here:

Electrical System

Volkswagen Cabriolet & Rabbit Convertible Technical Information

www.cabby-info.com

Amsterdcub · Nov 25, 2020

I took the cluster out again, retaped under the mylar and added the ground. I replaced the dash bulbs as well and now everything is working again inside. I bought a new reverse switch after checking the reverse bulbs were still good. I'll install that next time. Thanks again. Your photo guide for the print circuit and ground wire was super easy to follow.

Improving your Cluster Connections and ground.

Electrical System

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