Alteration of a lithium screwdriver device

Good afternoon. There is a charger from a mac allister screwdriver on nickel-cadmium batteries. Currently, the internal battery is replaced by lithium. The temperature sensor of them was soldered on the connector in the charger itself, added an adjustable lithium board, but in this form the charger turns on only for a couple of seconds and then thinks for 5 seconds, and the cycle repeats again. The question is how to make changes to the board so that the charger constantly gives out current without paying attention to the temperature sensor (i.e. remove it from the circuit). Thanks in advance!