Check engine light

HeberYJ

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Joined
Jul 14, 2020
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8
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Heber Arizona
My 1994 YJ, just bought it. The check engine light at night is faint red, not off but not full lit light when you put the key in. During the day with sun I didn’t notice it. Temp is 200- oil pressure is 40 running. Is this how the light always appears on these keeps?
 
I'd still check for engine codes but don't expect to see any because when lights do funny things like that it's usually a bad or weak ground and the current is finding other ways back around through different lights.

At that age there's bound to corrosion on every connector and you may want to pull out the cluster/ gauge panel and clean the connections or at least the connector plugs and pins with a spray contact cleaner.

That's my best guess
 
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Well AllRightyThen I drove my YJ tonight with the new LED's in the engine cluster and found my Check Engine Light is dimly lit too. Doing a little research I found the light actually always has power to it but the EMC controls the flow of electricity and with a normal light bulb it * should * go out but with the LED it's enough to stay dimly lit. A samll few ohm resistor will cure the light problem.

I'm still not totally ruling out a ground in my case because the wiring under the dash it a rats nest from different radios and lights being added over the years.
 
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Well AllRightyThen I drove my YJ tonight with the new LED's in the engine cluster and found my Check Engine Light is dimly lit too. Doing a little research I found the light actually always has power to it but the EMC controls the flow of electricity and with a normal light bulb it * should * go out but with the LED it's enough to stay dimly lit. A samll few ohm resistor will cure the light problem.

I'm still not totally ruling out a ground in my case because the wiring under the dash it a rats nest from different radios and lights being added over the years.
Mine did the same thing and I have no ground issues, my wiring is all factory and in good shape. The issue is the LED for sure. I decided LED on my CEL wasn't important enough to me and swapped it back to halogen. The rest of my LED idiot lights work well though so I left them. I only see the dim CEL at startup so it's no big deal overall.
 
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