Two thoughts.....
If you have a foot operated parking brake there should be a switch on the bracket that is pressed by the pedal arm when it is NOT depressed. There should be TWO wires attached to this switch, the one that attaches directly is the jacks the other one is the Engine control computer and dash display.
Thought 1: Make sure they are connected
Though 2: I often have to try 2 or 3 times to get that Q@#4q switch to close.