89 computer wireing
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Joined: Oct 2002
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From: del city,oklahoma
89 computer wireing
hi all i have a 79 f250 that has a 89 efi 460 swapped into it. everything works as should only one problem. i cant figure out which wire coming from the computer is the one i need for a check engine light. i jsut planned on putting a led light in the dash cluster assembly but dunno what wire to hook it to. if i understand right all i need to do is find that wire and hook it to a led. when there is a problem with the engine the computer grounds that circuit and in return the check engine light comes on. correct? so any info on what wire i need would be helpfull.
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Joined: Dec 2002
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From: Princeton, MN
89 computer wireing
Haynes Manual, 1987 through 1989 F-Series/Bronco wiring diagram page 12-39.
Looks like check engine light is fed from "PNK - LT GRN" wire from "EEC SELF TEST CONN"(ection). Current then goes out the voltmeter along with the Brake warning light, Engine warning indicator, Oil pressure guage, and Coolant temperature guage to ground.
Looks like check engine light is fed from "PNK - LT GRN" wire from "EEC SELF TEST CONN"(ection). Current then goes out the voltmeter along with the Brake warning light, Engine warning indicator, Oil pressure guage, and Coolant temperature guage to ground.
Posting Guru
Joined: Dec 2002
Posts: 1,246
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From: Princeton, MN
89 computer wireing
Sorry, been busy the last couple days. I don't know what you have for an instrument cluster or how the 79 is wired at all but I would think if you run the Pink - lt green wire to the light and then to ground it should work fine. The way to tell would be to hook it up and then start the engine. If the light comes on for a couple of seconds and then goes out like they do at normal startup then it is correct. If you have an 89 instrument cluster, the light may already be hooked up on the ground side through the voltmeter then to ground. If you don't have that cluster, I would just run to ground after the light.
