Having a tach cluster with a clock is a fantastic thing to have if you have one already. For some of us, this is a sought after modification. Some users have found that the clusters only came on Automatics. Some have also found that once they add it to their trucks, the clock either works or it doesn’t.
It seems that the trucks came wired through all years to have the tach work as soon as the cluster is plugged in. The clock however is hit or miss and this is the reason why. On the 86-89 models they were wired different. The 90-93 models the clock worked instantly.
When installing a cluster with tach, please move the speedometer cable to the far left. You may have to use a coat hanger to fish it through that hole. If you leave it in the middle, it will be at such a sharp angle that it will break.
To get the clock to work for those that are unfortunate, you have to add power, a constant power so it holds the time, unless you want it to start from 1:00 every time you turn the key back on.
The red circle represents the 2 contacts that are added. The pink circle is the one that needs to be hooked to constant power. (you could stop there if you want, your clock will work fine).
The other contact in the red circle is what dims the clock at night when you turn on the headlights. I just soldered it to a connection on the circuit board, there was already something soldered to that spot, so I just added this wire to it.
The white circle represents the spot it was soldered to. this way there is only 1 wire that is routed off the cluster, the one that goes to the constant power.
Other than the clock, and moving the speedometer cable over to the left everything was plug and play.
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