rikusb

I have been researching, searching, studying, and emailing people trying to find out what to do with this yellow C1 pin 18 accessory voltage wire on the E40 ecm. I've seen people ask about it on forums, but nobody has answered the question. I've found schematics showing the routing, but I'm confused by reading that. In the schematics it appears to be wired into two relays that appears to switch each other off and on so that they're not on at the same time. Honestly I can't really tell because I'm not an electrical engineer.
This is a swap harness going into a 79 trans am. The drop out is an automatic and I have the pedal, e40, and T42. The T42 also gets this accessory voltage
So what do I do with this wire? Wire it to key hot? Surely somebody knows this answer as I've been 20 internet tabs deep on two different browsers for days looking for this answer. Somebody help!
Thanks in advance.

Also where do I apply 12v for my transmission torque converter lock/unlock? Is it E40 C1 pin 32, TCM pin 25, or TCM pin 42?
Thanks again.

EFIHARNESS

on the E40 for standalone ,we don't use C1-18
Ign load to C1-19, C1-14
B+to C1-20
Sorry, I Don't know about the t42 connections. Steve

rikusb

Steve, thanks for the reply. So I assume that when you say you don't use it the computer still works as normal and that circuit is ignored?
I appreciate the information about the E40's supply voltages. Those I have a pretty good handle on as well as the voltage supply wires from C201 which power the left and right injectors and coils as well as voltage for the TCM. A/C power is there too, but I'm using the car's wiring for hvac controls.
E40's C2 and C3 connectors have been finished and pretty much all wires go from the engine sensors to the computer, so not much confusion or work needing to be done there. The C1 connector has the majority of the external connections, as you know. Is there a way that you could provide a quick rundown of those externals since it sounds like you've have a successful run at this? I just want to check it against what I think. If so that would be awesome. Thanks.

EFIHARNESS

All in C1
1=data +
2=data -
4= mil lamp
14, 19= ign load
36= fan control low
20= B+
48= Tach output
45=fuel pump control
22= pedal #1
41=Pedal #2
7,8=pedal low
29,35=pedal 5v+

rikusb

Thank you! You mentioned that you didn't know much about the T42, but do you have any information about C1-32 (stop lamp switch signal)? Or C1-38 (extended travel brake switch)? I believe one or both might get connected to my car's brake switch to signal the ecm about when the brakes are applied.
Thanks so much for that information Steve.

rikusb

Also I just thought of a couple others. Is C1-21 (VSS Signal) the signal to the speedometer?
C1-51 (Park/Neutral position signal) gets grounded while in park or neutral?
And is it better to use low speed signal for the fans instead of high speed? Or does it not matter which one?