Reset pin (15) behaviour of 4026 counter
I see one of two possibilities.

1) The ground pin of the chip is not connected to ground.  Check that pin carefully to make sure that it actually goes to your power supply (-) terminal.

2) The chip is faulty.  The reset pin might have seen an over-voltage excursion which destroyed the internal protection diode between the pin &amp; Vdd.  Your only option in that case is to replace the chip.