How do I wire the check engine light?

[1moretoy]

Hey guys got the truck fired last night and it sounds awesome. I have auto meter gauges with a billet bezel. I purchased some led lights from brothers to use as the blinkers and the engine light. Each light has a black and white wire. The blinker lights work fine. I have a wire from the harness for the engine light hooked to the black wire and the white wire is hooked to the lighting wire. Did have a couple codes but the light did not come on. Should the white wire be hooked to a power source instead. Pleases advise thank you

[ls1nova71]

Ignition power on the white wire. The PCM sends a ground to light the SES light.

[Andy4639]

I have the same question. The check engine light should be hooked to a switch on hot wire then go to computer and it will send it to ground if there is a reason for it. Correct?
If so I have mine hooked up backwards also.

[1moretoy]

Originally Posted by ls1nova71

Ignition power on the white wire. The PCM sends a ground to light the SES light.

So I was wrong I have the white wire going to the engine light wire and black to lighting. I just connected the black wire to the ignition source and left the white wire hooked to the pcm wire. The light is not coming on when I turn the key to the on position. If the light only has two wires does it matter what color I use? Should the light come on in the on position?

[ls1nova71]

Originally Posted by 1moretoy

So I was wrong I have the white wire going to the engine light wire and black to lighting. I just connected the black wire to the ignition source and left the white wire hooked to the pcm wire. The light is not coming on when I turn the key to the on position. If the light only has two wires does it matter what color I use? Should the light come on in the on position?

It doesn't matter on a light bulb which is power and which is ground, but on an LED it does. The power has to be on the white and ground on black. Hook the black wire to the PCM and the white wire to ignition power. Light should come on whe n the ignition is on and engine not running.

[dman1982]

Originally Posted by 1moretoy

Hey guys got the truck fired last night and it sounds awesome. I have auto meter gauges with a billet bezel. I purchased some led lights from brothers to use as the blinkers and the engine light. Each light has a black and white wire. The blinker lights work fine. I have a wire from the harness for the engine light hooked to the black wire and the white wire is hooked to the lighting wire. Did have a couple codes but the light did not come on. Should the white wire be hooked to a power source instead. Pleases advise thank you

that looks freaking awesome!!!!....but no clock? lol

[1moretoy]

Originally Posted by ls1nova71

Ignition power on the white wire. The PCM sends a ground to light the SES light.

Originally Posted by dman1982

that looks freaking awesome!!!!....but no clock? lol

Thank you ls1nova I will try and switch the wires tomorrow. Thanks dman this is what I have been working on. Cant wait to drive it. What is a easy way to post a video?

[dman1982]

Originally Posted by 1moretoy

Thank you ls1nova I will try and switch the wires tomorrow. Thanks dman this is what I have been working on. Cant wait to drive it. What is a easy way to post a video?

Also badazz...YouTube is about the easiest from my experience, I just hooked up my CEL, it was pretty easy...it's on my build...well the location anyways

[71chevystep4x4]

Ok, so I'm the 3rd guy that has it hooked up wrong. Mines just a two prong light from the parts store, has the white wire from PCM on one, and I grounded the other. So I just need to remove the ground, and run ignition source to it? Luckily I have never brought up any codes, but always wandered if the light was hooked up right.

[ls1nova71]

Originally Posted by 71chevystep4x4

Ok, so I'm the 3rd guy that has it hooked up wrong. Mines just a two prong light from the parts store, has the white wire from PCM on one, and I grounded the other. So I just need to remove the ground, and run ignition source to it? Luckily I have never brought up any codes, but always wandered if the light was hooked up right.

If your light is a light bulb, then yes, just remove your ground and hook it to a key on ignition source. If its an LED, then the black (ground lead) needs to go to the PCM since they won't work when wired backwards. The check engine light should come on whenever the key is on and the engine isn't running. If it doesn't, either your light is bad or its wired wrong.

[1moretoy]

Originally Posted by ls1nova71

If your light is a light bulb, then yes, just remove your ground and hook it to a key on ignition source. If its an LED, then the black (ground lead) needs to go to the PCM since they won't work when wired backwards. The check engine light should come on whenever the key is on and the engine isn't running. If it doesn't, either your light is bad or its wired wrong.

Thank you. I re-wired it and now the engine light works and I have no codes.

[Andy4639]

1moretoy,
glad you got it figured out.

I went outside tonight and rewired mine. It's also working but I have one more question for everyone.
Mine is a LED light and it lights up fine as you can see in the picture.



The only thing is after I crank the truck up it flickers not very bright like the picture but really dim. What do you think it could be.
Oh the computer isn't hard mounted so it's not grounded through the frame are cab back to the battery. I don't know if that would make a differance are not.

[ls1nova71]

LEDs will glow slightly when ever the key is on, that's normal. It has something to do with the circuitry in the PCM and the fact that LEDs take very little voltage to light up. If you switch to a regular light bulb it won't do that.

[dman1982]

Did you get it from orileys? If it's the same one I got the white wire is negative and the black is ground

[71chevystep4x4]

Got it at Baxters, and it doesn't have wires, just male ended prongs. But she works now for the first time in a year. Thanks Ls1nova71

[dman1982]

Oh gotcha, I'm used to black being ground, mine was opposite, but it came on today for the 02, holy crap it's bright