2002 astra bertone 1.8 16 V coupe?

Hi all my astra coupe is fitted with abs, but when replacing the front struts i noticed the left front wheel hub has no abs connector or wiring harness unlike the rest of the hubs on the car.

My question is this people.Has the previous owner fitted a none abs five stud hub and pulled the wiring harness from the connector which is clearly visible under the wheel arch ,and is this the cause of my randomly flashing traction control light under normal driving conditions.

Or is this correct on this model of astra g.

Only asking for advice because I'm no mechanic but shouldn't all four wheels have sensors for abs to work correctly?.Also no abs warning on dash either.

Thanks to all that take the time to answer .