After replacing the alternator and the battery on our '99 Deville, we are not getting any power through to the ignition system. I have checked for loose connections, ground is good, alternator tested good and battery is new. What should I check for now? Before replacing these items, testing showed a bad alternator and a very old battery. Thanks!
My car has 110000 miles.
My car has an automatic transmission.
First, you should check for injector pulse and fuel pressure. If either of these are not working, then there are some specific diagnostic paths to follow. If it is only spark you are missing, check all the fuses.
Make sure to check them all as we never know if one fuse supplies power to another. If all the fuses are good, check for power and ground at the ignition module. If you don't have power or ground at the module, you will need to trace the wires back until you find the bad connection. Check harness connectors and fuse blocks before you start tearing into a harness.
I mentioned the injector pulse first. This is best tested with a noid light. If you don't have injector pulse, the most common cause is a bad crank sensor. This can be checked with a scanner. If you don't have a crank signal on the scanner, hopefully there is a code to guide the diagnosis.
If you require more assistance with this diagnosis, I recommend the following inspection to help you out. A certified professional from YourMechanic can come to your car's location to inspect the vehicle's loss of power so that this can be corrected.
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