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Q: Installed a new ignition harness after the old one required repeated key giggling to start the car, now won't start

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First I installed a PCM ignition relay board successfully and then found out it was the ignition switch harness that needed replacement. I installed an Autozone harness and now the car won't start. It turns over fine and the dash lights work put won't start. I suspect something to do with the immobilizer because the door alarm no longer activates or sounds off. Not sure why when I did not replace the actual mechanical key switch tumbler and I never removed the immobilizer and I'm using the original key. I re-installed the old harness that did work with a giggle or two first and now it no longer works...the car still won't start. My issue is the car has a aftermarket stereo and I'm unable to locate the security code/reprogram number that was in the glove box. Please help. Mel

My car has 130000 miles.
My car has a manual transmission.

When you replaced the harness you made the immobilizer lose its memory. The car is not starting because it needs to re learn the key values. I recommend having the vehicle checked by a certified mechanic to verify the cause of the starting issue. A technician from YourMechanic can do a thorough diagnosis and help you successfully relearn the immobilizer if you need assistance.

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