In previous works we have investigated the degradation in the ON-current due to self-heating effects in 10 nm channel length nanowire transistors. In this work we examine the simultaneous influence of self-heating and random trapping effects on the magnitude of the ON current. Both positively and negatively charged single traps are considered in the analysis. Our investigations suggest that self-heating effects affect the ON-current in two ways: (1) by lowering the barrier at the source end of the channel, thus allowing for more carriers to go through, and (2) via the screening effect of the Coulomb potential. Namely, presence of more carriers in the channel means more screening and more screening means less impact due to the potential barrier of the negatively charged trap at the source injection barrier, but this at the same time means more self-heating.