need to add a engine light
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Fleet Mechanic
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From: va
need to add a engine light
I have an 87 f150 4.9 with no engine light. On the wiring diagram there's a Pink-Lt Green wire thats for a check engine light on the self test connector. I think you guys with 88 and 89 must have a light? How can I jerry rig something that i can mount under the dash?
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Joined: Sep 2004
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From: SC lowcountry
Assume you are talking about Check Engine light- there is one in Dash should come on briefly with switch in "on" position - if it doesn't bulb is burnt out or removed from dash to get rid of the nuisance. Check owner's manual should be at lower right of instrument panel if I remember correctly. Pink light green lead feeds Check engine light.
Lead Driver
Joined: Nov 2002
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From: Concord, NC
I had the same problem with my '87, and here's what I did. There is a check engine light in the dash, just no wire running to it, nor is there a bulb. I removed the pin from the dash harness for the EMISS light (which I unplugged and is useless anyway) and inserted it at the location to operate the check engine light. I spliced a wire on to the pigtail from the pin and ran it to the big junction block of wires going through the firewall - I had to open up a hole in the plastic backing plate to allow a wire through. I had some pins that fit that connector from a mustang harness used in my mass air conversion, so I inserted a pin on both sides of this junction block, the one on the inside of the cab going to the pin that I moved at the instrument cluster, and the under hood side going to the STO wire coiming from the computer. So now the check engine light in the dash works on my truck. If you don't want to do all that, just wire a small light, maybe an LED or something in under the dash. You will need a switched power source for the light (+12V) and then run a line to the STO wire from the computer as the ground for the light.
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Fleet Mechanic
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From: va
No check engine light
Originally Posted by 95X15
Assume you are talking about Check Engine light- there is one in Dash should come on briefly with switch in "on" position - if it doesn't bulb is burnt out or removed from dash to get rid of the nuisance. Check owner's manual should be at lower right of instrument panel if I remember correctly. Pink light green lead feeds Check engine light.
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Fleet Mechanic
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From: va
wiring a check engine light
Originally Posted by EPNCSU2006
I had the same problem with my '87, and here's what I did. There is a check engine light in the dash, just no wire running to it, nor is there a bulb. I removed the pin from the dash harness for the EMISS light (which I unplugged and is useless anyway) and inserted it at the location to operate the check engine light. I spliced a wire on to the pigtail from the pin and ran it to the big junction block of wires going through the firewall - I had to open up a hole in the plastic backing plate to allow a wire through. I had some pins that fit that connector from a mustang harness used in my mass air conversion, so I inserted a pin on both sides of this junction block, the one on the inside of the cab going to the pin that I moved at the instrument cluster, and the under hood side going to the STO wire coiming from the computer. So now the check engine light in the dash works on my truck. If you don't want to do all that, just wire a small light, maybe an LED or something in under the dash. You will need a switched power source for the light (+12V) and then run a line to the STO wire from the computer as the ground for the light.
Lead Driver
Joined: Nov 2002
Posts: 9,557
Likes: 44
From: Concord, NC
I just used the pin on the cluster harness from the EMISS light - I moved the pin and about a 4" lead of the wire to the pin location that corresponds with the Check Engine light location. I also unplugged the EMISS timer module under the dash. I also moved the bulb and bulb socket down to where the Check Engine light is.
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Joined: Jun 2003
Posts: 352
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From: Tillamook, Ore
Originally Posted by EPNCSU2006
I had the same problem with my '87, and here's what I did. There is a check engine light in the dash, just no wire running to it, nor is there a bulb. I removed the pin from the dash harness for the EMISS light (which I unplugged and is useless anyway) and inserted it at the location to operate the check engine light. I spliced a wire on to the pigtail from the pin and ran it to the big junction block of wires going through the firewall - I had to open up a hole in the plastic backing plate to allow a wire through. I had some pins that fit that connector from a mustang harness used in my mass air conversion, so I inserted a pin on both sides of this junction block, the one on the inside of the cab going to the pin that I moved at the instrument cluster, and the under hood side going to the STO wire coiming from the computer. So now the check engine light in the dash works on my truck. If you don't want to do all that, just wire a small light, maybe an LED or something in under the dash. You will need a switched power source for the light (+12V) and then run a line to the STO wire from the computer as the ground for the light.
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Lead Driver
Joined: Nov 2002
Posts: 9,557
Likes: 44
From: Concord, NC
Well I re-wired the engine harness for mass air, so I figured might as well do this while I was wiring. It's not unnecessary b.s. to me. I can now see when the check engine light comes on, so I know when there is a problem. It is much easier and I can check the codes anywhere I am now, without having to have my clunker of an analog volt meter. Plus I liked the challenge of figuring out how to wire it - I'm studying to be an engineer, these things I like to do. Unnecessary? maybe. B.S.? I think not. 
Last edited by EPNCSU2006; Nov 6, 2004 at 08:15 AM.
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Fleet Mechanic
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From: va
getting trouble codes with engine light
Originally Posted by Egor
Or you could just check your codes once in a while if you feel you have a problem. This sounds like a bunch of unnecessary BS to me.