Two 12 pin connector housings from stock 914 D-Jet ignition harnesses are shown below. The left-side housing is from a 1970-71 914, the right side from a 1973-76 ignition harness. There are three differences between these visble in the photo. Who will be the first to identify all three differences? No prize other than bragging rights. Consider this practice for the next WCC tech quiz.

The heater blower wiring is in the early harness, because the heater blower is mounted on the center of the engine 70-72. Can't remember what the other difference is. I bought a decent early harness & got it to work on my 73 by pulling some of the wires out of it. Seems like there was a jumper across the 73 connector that I had to use on the early connector.

Color striped wiring, seat belt linking terminal and different connector housing lock.
All 3 are purely guesses. I normally sell my 914 when I have electrical or mechanical problems. 32 and counting.........

Reverse switch wires are in different positions. I think.

You were asking the difference, I will take that literal.

1) Red and white wire are on different pins

2) One on left has 4 pins on top bank of pins one on right has 5.

3) One on left has 8 wires, one on right has 9.

Isn't the starter relay wire a thicker gauge in the later harness?

Some of you are on the right path...'theres 1 more pin on the 73-76 harness'...but we need more detail...

McMark nailed the first of three answers. The yellow wire is the starter wire and it is a larger gage in the 73-76 ignition harness.

Took some research and some creative thinking/reading.

On the early harness, pin 11 goes to the heater blower. On the later harness, pin 11 loops back to pin 10 which connects to the heater blower through the body harness, not the engine harness.

Whew!

Finally, and not very confidently, it appears the that bakelite casing is slightly different where the wire bundle enters/exits.