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Trust My Mechanic

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Check Engine Light Comes On Dim

Austin Davis, November 7, 2012April 5, 2013

Reader Question

I have a 2003 Ford Focus ZX5.I’m wondering what the following check engine light situation means. When I start the car the check engine light shines brightly to let me know it is working and then turns off like all the other warning lights.

Sometimes, but not always as I drive, this light will come on but very, very dimly. Occasionally the light will get brighter as I drive but it is still hardly noticeable and not even close to the normal brightness.

Even when I shut off the car, the light is extremely dim but eventually shuts off.

I can’t tell if I really have an engine problem because the light is so dim and not normal brightness.

Any suggestions on what this all means.

Thank you.
Brad

Hi there Brad,

Personally I have not had an experience like that before, but the first thing that came to mind when I read your email was a possible problem with the ignition switch or the ignition lock cylinder (the part you put the key in).

Next time the check engine light comes on dim again, try moving the ignition key just a little in either direction to see if the light brightness changes.

My thought is, the ignition key/switch is worn and the ignition key has backed up just slightly as you drive, so there is some power going to the dashboard lights just like it does when you put the key in the ON position, and all the lights light up.

I found lots of complaints about the ignition switch . So you might want to check that out. That s my best guess anyway.

Ford Focus Ignition Lock Cylinder Failures

Blessings,
Austin Davis

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