that a 24v truck or 36v truck?
the part number you give is for the 36v truck, there is a service gram out on this part also defining which one goes with which serial number range and according to that the A265 series trucks came with a 24v or 36v IFB.
According to serial number this truck should have come with this part number for this IFB, 2089014 and flight systems/TVH reman number should have been 1706682 (OEM) or 1706682R (reman).
The number you gave does show up but is not the one highlighted per serial number range.

and have you thought about trying an OEM hyster part instead of those TVH/flight systems reman parts?

plus i notice this board has fuses for accessories like lights etc, what do you have connected to this truck? are there any addon lights not part of the hyster design? aftermarket lights?

and lastly have you checked for voltage to the frame?
you might have a shorted circuit elsewhere causing this, you have have to back probe the circuit to find it.