We present a systematic investigation on the effects of interlayer coupling on the magnetoresistance (MR) behavior of Ni80Fe20/Ru(\( t_{Ru}\)/Ni80Fe20 trilayer nanostripes (NSs) as a function of temperature T . By changing \( t_{Ru}\) from 0.8 nm to 1.7 nm, either a ferromagnetic or an antiferromagnetic (AFM) type of interlayer coupling was achieved, leading to a markedly different MR behavior. We observed that the MR response is a superimposition of AMR and GMR effects, and it is significantly dependent on temperature. For AFM coupled NSs, there is a transition from a pure AFM state to a reversed spin-flop phase due to enhanced ferromagnetic pin-hole coupling at low T. Our experimental results are in good agreement with micromagnetic simulations.