Did you test across the GPR with a test light or a meter? If it was with a meter, what Voltage did you get on the "NO/normally open" side? I have heard there should be no more than a 0.3V drop across these contacts. If more than that, they may be slightly corroded and not as conductive as they once were. From what I understand, GP's need a good solid 12V or more to light properly.