On modern vehicles the instrument dials are operated by the use of stepper motors.
These motors can arrive at a determined point depending on the power signal sent
to them. One of our dials were beginning to act very strangely (the oil pressure
dial was fully deflected out of bounds, and the speedometer needle would rest at
45 MPH and sometimes wouldn’t move at all). Fortunately all of the motors (6 total
for our 2005 Trail Blazer) are exactly the same and more fortunate is that replacement
motors can easily be purchased on eBay for about $35.00 (even came with LED bulbs
for the dash if needed).
First step to replace the motors is to remove the instrument cluster from the
vehicle. This will take a little bit of time if it’s your first time at doing so.
Just got slow and careful.
Once the cluster is free from the dash you can begin to take it apart. Often it
is only held together with slide in tabs and is relatively easy enough to disassemble.
An important step is to take some tape and use it to mark where the needles rest
at their left most state. This allows you to accurately set the needles back in place
and keep things calibrated.
Now, you need to get down to the back of the printed circuit board in order to
use a soldering iron to remove the old motors. Installation of the new motors is
relatively easy as the backs of the motors are fitted with keyed tab protrusions
that only allow you to install it one way (dummy proof). Resolder the 4 terminal
posts to the circuit board and refit the faceplate back in. Next comes time to install
the needles and this is where you will use your previously drawn marks. Start with
the needles at the 12 o’clock position when you place it on the stem. Then turn it
left until it is on the mark.
Reassemble the entire cluster back together again and reinstall into the vehicle.
You should be all set.