1984 C207 decode
#1
1984 C207 decode
I appreciate the help I've received on engine wiring. My latest question is on the C207.
What connections do I need for my LS swap?
Which connection goes to the check engine light?
And, there are 2 wires for a backup switch / reverse lights, and there are 2 wires for P/N park neutral. Do I connect those to the T56 transmission?
L4 is for the 4 cylinder engine, so I know that doesn't apply (I have the 8 cylinder trans am). TCC is for the automatic transmission, so I don't think I need that. The speedometer is mechanical, so I don't think I need vehicle speed sensor / VSS data. Thanks again for any help.
What connections do I need for my LS swap?
Which connection goes to the check engine light?
And, there are 2 wires for a backup switch / reverse lights, and there are 2 wires for P/N park neutral. Do I connect those to the T56 transmission?
L4 is for the 4 cylinder engine, so I know that doesn't apply (I have the 8 cylinder trans am). TCC is for the automatic transmission, so I don't think I need that. The speedometer is mechanical, so I don't think I need vehicle speed sensor / VSS data. Thanks again for any help.
Last edited by johnw999; 02-14-2017 at 04:31 PM.
#2
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Car: 88 Trans am
Transmission: T56
Axle/Gears: C4 IRS 3.42
Re: 1984 C207 decode
Is that actually what your C207 looks like ? What engine came in your car originally ?
I have a partial harness from an 85 carbed car and the fender grommet and C207 have 3 wires. Three total. Wonder if its a Cali emissions thing.
Anyways, The backup light switch on the manual trans is wired to the c100 connector and into the dash from there. On Auto cars the switch is on the shifter and connects to the dash harness. On later year cars anyways. Looks like yours goes thru the c207 ?
I have a partial harness from an 85 carbed car and the fender grommet and C207 have 3 wires. Three total. Wonder if its a Cali emissions thing.
Anyways, The backup light switch on the manual trans is wired to the c100 connector and into the dash from there. On Auto cars the switch is on the shifter and connects to the dash harness. On later year cars anyways. Looks like yours goes thru the c207 ?
Last edited by 88Greg; 02-14-2017 at 08:19 PM. Reason: Backup light info
#4
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Re: 1984 C207 decode
The oil pressure gauge wire is the only one that will be of use to you if you're using a factory LS harness.
#5
Re: 1984 C207 decode
The diagram says the oil pressure wire is for the 4 cylinder. My oil pressure is actually through the C100. My Trans Am has a stick shift, so the two T-5 backup switch wires applies to me. Where do I connect those wires? Do they both turn on the backup lights?
#6
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Car: 88 Trans am
Transmission: T56
Axle/Gears: C4 IRS 3.42
Re: 1984 C207 decode
Try jumpering those 2 together and see if it turns the reverse lights on. The reverse light switch on the trans does just that.
#7
Re: 1984 C207 decode
I think you're right. I decoded my C207. The diagram that I got from the internet was mostly correct. It had the back light wires switched, but that really doesn't matter. Like you said, both go to the transmission, and the transmission completes the circuit when in reverse. Check out my decode and the picture of the transmission connection.
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#8
Re: 1984 C207 decode
So, should I only keep the blue and green back-up wires, or should I also include another connection for the check engine light? ALDL means assembly line data link...it's probably not the check engine light. Maybe it's C - white/green light driver / ECM?
#9
Re: 1984 C207 decode
Through some searching, I've determined that the "light driver" connection is for the check engine light, but I need to just bypass it with my own wiring. This was in another thread:
"Cut wire on Pin C on car-side of connector and route directly to the 'check-engine' light (the original circuit goes through a 'light driver module' which will not work with the TPI ECM. I had to modify the light socket because it originally plugged into a ribbon cable that I couldn't easily tap into. The wire from Pin C is the ground for the light so you also have to run an ignition circuit"
"Cut wire on Pin C on car-side of connector and route directly to the 'check-engine' light (the original circuit goes through a 'light driver module' which will not work with the TPI ECM. I had to modify the light socket because it originally plugged into a ribbon cable that I couldn't easily tap into. The wire from Pin C is the ground for the light so you also have to run an ignition circuit"
#10
Re: 1984 C207 decode
Let's say I just want to keep the check engine light off without removing the bulb. From a wiring schematic, I see that the ECM competes the circuit to the light driver module by establishing a ground. So, if I run the white/green wire from the C207 to a ground, would that keep the light off?
#11
Re: 1984 C207 decode
Ahh - I just went ahead and pulled the bulb. It wasn't as hard as I thought it'd be. I still have most of the dash apart for the headlight switch replacement. Problem solved
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