I was told, and have read before that all 68-72 Cutlass's are prewired for certain accessories regardless of whether the car was ordered with them or not.

For example, the clock. I went to put a standard clock in the car this morning, and I can't find the wires tucked back in the dash anywhere.

Car is a 1972 Cutlass S, factory bucket/console car.

 

ALL cars made come with the connectors pre-installed in the harness for options. Your clock feed is there. Keep looking. There should be an orange wire with a single connector that's on the same circuit as the cigarette lighter.

 

They were prewired for only some minor options; your clock is one of them. You should also find a gray wire for the clock light back there somewhere...
Major options like cruise, power windows, seats, trunk, got their own wiring harnesses.

 

What about the tach for '68?

 

The Tic Toc Tac uses the same orange and gray wires as the clock, but has a separate harness (just a single wire with a fuse if I remember correctly) that connects to the negative side of the coil.

 

The power wire for the trunk light is there also. It is located just to the left of the left side trunk hinge. I believe the power wire is there also for a power driver seat. It is a large orange wire located in the plastic loom under the seat in case any one wanted to know.

 

No electric seat pre-wiring in my 72. That might be true if the car came with power windows or such...