When I put the key in my 1995 Jeep Wrangler
and try to start it, the starter turns over but no lights come on. After a few tries, a clicking noise comes from the power distribution center in the engine compartment. It slows down after a minute or two, and as it slows down the service-engine light flashes. Then when the clicking stops, the light stays on and it will start. It gets no fire. The starter will crank but that’s all. The service-engine light and shift light don’t come on until the clicking stops. The only light that comes on is the seatbelt light. The clicking comes out of the starter and PCM relays under the hood. I know those aren’t the problem, because I’ve replaced them both. I also installed a new starter. Also the fuel pump will not come on until the service-engine light comes on.
Answer: This may end up requiring a technician with a wiring schematic, a digital multimeter, and a scan tool to check for trouble codes. However, try a few simple things first. You want to focus on the service engine light. If it does not light up with the ignition on (not cranking), that means the main computer (PCM) isn’t functioning correctly. First, turn the ignition on and jiggle the key and the lock cylinder, even bang on the steering column with your fist. If you see the service-engine light come on or even flicker, the problem is either the ignition switch or a nearby connection. Second, get someone to watch the instrument panel (with the ignition on) while you work your way around the vehicle. Go under the left side of the dash and find the PCM (fairly big silver or black box). Jiggle the wiring leading to it, and tap on the box with the blunt end of a screwdriver. Again, you’re looking for the service-engine light to come on and lead you to the problem. If jiggling the harness causes the light to come on, that indicates a bad connection. If tapping on the PCM triggers the light, the PCM needs to be replaced. Third, go under the hood and jiggle and tap (lightly) on connectors, relays, and ground connections that may be feeding power or ground to the PCM. Focus on the fuse/relay block, cables leading from the battery, and ground connections on the engine, particularly on the right side and the back of the alternator.
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