'8079 ecm and the "Light driver module"
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Joined: Mar 2004
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From: Kansas, where the wind howls
Car: 84 Z28 H.O. w/Megasquirt II
Engine: semi-stock L69
Transmission: T-5 non W/C
Axle/Gears: 3.73 open
'8079 ecm and the "Light driver module"
I've converted to a Megasquirt, and I'd like to take advantage of the "Check Engine" light in the form its in now.
I could apply either 12V, 5V, or ground to the white/green wire whenever I'd like, but I don't know which will turn it off. I'd rather not find out the hard way.
What signal does an 84 ccc ecm('8079 ecm) apply to turn it off?? If it grounds the wire, am I gonna need any resistance? Any idea how many amps I'd need to sink/supply?
I could apply either 12V, 5V, or ground to the white/green wire whenever I'd like, but I don't know which will turn it off. I'd rather not find out the hard way.
What signal does an 84 ccc ecm('8079 ecm) apply to turn it off?? If it grounds the wire, am I gonna need any resistance? Any idea how many amps I'd need to sink/supply?
Joined: May 2004
Posts: 2,262
Likes: 1
From: houston
Car: 83 POS monte carlo 2015 chevy P/U
Engine: 92 5.7 tpi 5.3
Transmission: 700r4 6L60E
Axle/Gears: 2.42 too high
Re: '8079 ecm and the "Light driver module"
my books show 12 volts on terminal C (white/green) from the lamp driver module going to terminal G on the ECM, the ECM grounds it to turn the CEL off.
the current should be more than low enough for the MS to handle.
sense the MS can supply a ground to turn on the CEL, you can remove the lamp driver module & tap into terminal A at & be good to go.
the current should be more than low enough for the MS to handle.
sense the MS can supply a ground to turn on the CEL, you can remove the lamp driver module & tap into terminal A at & be good to go.
Thread Starter
Member
Joined: Mar 2004
Posts: 388
Likes: 0
From: Kansas, where the wind howls
Car: 84 Z28 H.O. w/Megasquirt II
Engine: semi-stock L69
Transmission: T-5 non W/C
Axle/Gears: 3.73 open
Re: '8079 ecm and the "Light driver module"
Thank you. Exactly what I was looking for. I'm gonna drive it with a transistor, and would like to keep the current under 80ma. I'm assuming since the factory went through the trouble for a seperate module, the signal will be below this threshold.
Not sure where the "terminal A" you mentioned comes in, but no matter. I'd like to keep the light driver module right where it is for now,.
Not sure where the "terminal A" you mentioned comes in, but no matter. I'd like to keep the light driver module right where it is for now,.
Last edited by pizza_guy; Jun 29, 2007 at 07:20 AM.
Joined: May 2004
Posts: 2,262
Likes: 1
From: houston
Car: 83 POS monte carlo 2015 chevy P/U
Engine: 92 5.7 tpi 5.3
Transmission: 700r4 6L60E
Axle/Gears: 2.42 too high
Re: '8079 ecm and the "Light driver module"
no problem
im not sure if GM even knows why they used a driver module in the beginning.
some of the early GM manuals i had recommended replacement of the driver module if the ECM was found to be the cause of a constant on or non-working CEL.
i don't know for certain what one of those little 194 bulbs draw, im thinking around 50ma.
the terminal A i was talking about is on the lamp driver module in case you decide to remove the driver module.
im not sure if GM even knows why they used a driver module in the beginning.
some of the early GM manuals i had recommended replacement of the driver module if the ECM was found to be the cause of a constant on or non-working CEL.
i don't know for certain what one of those little 194 bulbs draw, im thinking around 50ma.
the terminal A i was talking about is on the lamp driver module in case you decide to remove the driver module.
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