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Instrument cluster removal, high beam indicator dimmer, adjusting the speedometer
Instrument cluster removal and high beam indicator dimmer (and adjusting the speedometer needle)
This article shows how to DIY remove the instrument cluster on a Volkswagen Jetta TDI or dim the high beam indicator. Also shown is how to adjust the speedometer needle.
The procedure is the same on VW Golf TDI and similar on the New Beetle. If you want to change the gauge faces or needles then the cluster needs to come out. I also dimmed the high beam headlight indicator on the cluster because the instrument panel dimmer doesn't dim it. The bright blue LED degrades night vision and I find it extremely annoying. I used only a sharpie marker to dim it because it's not safe to completely block the LED - it reminds you when the high beams are on.
While the cluster was out, I also polished the clear plastic cover because it was scratched from cleaning with paper towels. As good practice, always use water and plush microfiber towels to clean the soft plastic and prevent scratches. While your lens is just plastic, some fancier cars use anti reflective coatings which makes it very difficult to polish.
Long story short, German cars allow the speedometer to read fast by a tenth of true speed plus 4 kph but never slow.
From car and driver :"US manufacturers voluntarily follow the standard set by the Society of Automotive Engineers, J1226...manufacturers are afforded the latitude to aim for within plus-or-minus two percent of absolute accuracy or to introduce bias to read high on a sliding scale of from minus-one to plus-three percent at low speeds to zero to plus-four percent above 55 mph. And those percentages are not of actual speed but rather a percentage of the total speed range indicated on the dial. So the four-percent allowable range on an 85-mph speedometer is 3.4 mph, and the acceptable range on a 150-mph speedometer is 6.0 mph...The European regulation, ECE-R 39, is more concise, stating essentially that the speed indicated must never be lower than the true speed or higher by more than one-tenth of true speed plus four kilometers per hour (79.5 mph at a true 70). Never low. Not even if somebody swaps a big set of 285/35R-18s for stock 255/45R-16s."
The speedometer is read from a speedometer sensor on the transmission. The sensor is on the differential, sticking straight up. The easiest way to adjust a fast speedometer is to first remove the instrument cluster and then pop the needle off. Then just put it back on a little bit counterclockwise. In other words, place it so that when the car is stopped, it reads -3 mph. See the TOS Agreement for the full legal disclaimer before doing any work on your car.
Also see speedometer adjustment using VCDS for some more tips to adjust the speedometer.
Variance in wheel sizes, tire inflation, wear, and sizes can also change the speedometer and odometer reading by changing the rolling diameter. Take this into account when considering the speedometer and/or odometer error. See 1000q: wheel/tire calculator to see some examples.
Disconnect the battery negative cable.
instrument cluster removal
Position the steering wheel all the way down and forward. Remove the upper half of the steering column plastic cover (2x phillips screws).
The lower plastic gauge surround is held in by 2 clips (arrow in pic below). Gently pull it out to avoid breaking the clips. Here is a picture of the 2 clips after removal.
If the clips don't want to release you can still access the 2 torx screws holding the instrument cluster by lifting the steering wheel column cover up.
Pull the instrument cluster forward and remove the 2 blue and green plastic plugs to release the cluster. Pivot the locking lever out and up to release each plug.
*NOTE - you can remove and install the same instrument cluster without a problem. However, if you are installing a new or used instrument cluster you must know the SKC and use a VCDS cable from ross tech to sync the cluster. This is because of the immobilizer. For more on the immobilizer system, see 1000q: immobilizer FAQ.
Cluster disassembly and high beam dimmer mod
To remove the clear plastic cover, flip the cluster over. Remove the 2 torx screws and pry the clips slightly out. It's difficult to get fine scratches to show up in a picture so here's the "after" polishing picture of the cover. Remember, do not use paper towels on soft plastic or paint. A microfiber towel + plastic specific polish like mother's plastix+ elbow grease works best because the plastic is fairly soft. Use another microfiber towel to buff away the polish.
To remove the gauge faces, insert a pry underneath the plastic gauge faces (to avoid scratching the gauge face) and evenly pry the needle up.
If you want to dim the high beam indicator, just remove the coolant temp needle. Remove as few needles as possible to pull up the gauge face. Then use a sharpie marker to fill in the back of the high beam indicator spot. A few coats of marker reduced the brightness just to the same level as the other gauges. I would not use paint since this would block the indicator.
Here is a simulated after and before picture. It was impossible to get an exact comparison because of picture exposure. The first picture shows the "after" with the indicator about the same brightness as the rest of the cluster. The second picture shows how bright the indicator normally is compared to the other gauges.
When replacing the needles, just set them to their normal "0" position when fully counter clockwise. Rotate the needles to the left and right stops to confirm their position.
Fixing a fast speedometer
In the picture above, the speedometer needle appears to be slightly slower than 0. This is partly because of the camera angle and partly because during installation, I put it back to read a little below 0 mph when stopped. While speedometer error is often a percentage error instead of a straight mph error, this will help correct it across the most common driving speeds.
You could also use taller tires which would also raise the car a little and may give slightly taller effective gearing but this would also throw off the odometer. To see the effect of taller tires on gearing, see the wheel and tire gearing calculator linked above.