This past week I installed an aftermarket tachometer with the help of an online Toyota “expert”. I followed all his instructions and when all was said and done the truck would not crank to start. I can push start it and it runs fine. I went back to same expert and he said all the work looked good my ignition switch was bad. Today I installed a new ignition switch and it made no difference. I was told by someone else to check the fusible links , could one of these be causing my problem? If so where do I locate them? What else could cause my problem?