How difficult is it to use a factory check engine light (89 Chevy truck)?
11-11-2013, 04:04 PM
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How difficult is it to use a factory check engine light (89 Chevy truck)? I just picked up a 1989 Chevy C1500 with a swapped in 4.8.
The check engine light is on, presumably because the factory ECU is gone.
The painless harness has leads for a CEL. Can I simply tap them into the dash harness?
Does a CEL come on because of a signal, or lack of one?
I'm hoping someone who has a GMT400 swap going can answer specifically.
Thanks in advance!
The check engine light is on, presumably because the factory ECU is gone.
The painless harness has leads for a CEL. Can I simply tap them into the dash harness?
Does a CEL come on because of a signal, or lack of one?
I'm hoping someone who has a GMT400 swap going can answer specifically.
Thanks in advance!
11-11-2013, 10:02 PM
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The LS CEL is wired with 12v constant on one side. The PCM grounds the other wire to turn the light on.
If your harness has wires for the CEL you can just run them to the existing light, polarity won't matter since its just a light bulb.
If your harness has wires for the CEL you can just run them to the existing light, polarity won't matter since its just a light bulb.
11-12-2013, 01:21 AM
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Thanks!
The confusing thing is that if the stock ECM is gone... what is grounding the stock CEL? Thats what had me wondering if a lack of signal put it on.
Looks like the next step is a wiring diagram.
The confusing thing is that if the stock ECM is gone... what is grounding the stock CEL? Thats what had me wondering if a lack of signal put it on.
Looks like the next step is a wiring diagram.
11-12-2013, 11:50 PM
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Upon further reflection, though, the factory ECU my still be in place. I had it in my head it would be under-hood. However, this is old enough to have the computer still buried in the dash. When I get the truck back, I'll look into that. It is getting some small paint repairs.