stonecoldtx

Hi, All

I have installed a Chevrolet Performance Parts "Connect and Cruise" LT1/8L90E "E-Rod" kit into my 57 Chevy Sedan Delivery . . . I'm working on wiring everything up, and I'm using the stock Camaro/Cadillac ATS shifter and cable . . . I'm also using a set of Dakota Digital VHX Gauges and pulling the engine/transmission information from the OBD-II port using one of their modules.

I expected there to be some connections on the shifter that I could use to wire in the Neutral Safety switch and reverse lights, but the only connection to the shifter is a 2-wire connector that provides power to the Shifter Interlock when the brake is pressed . . .

I know that the Dakota Digital system is able to see which gear is selected, and after some research, I found that the BCM provides the data to the stock Gear Selection Module mounted in the Shifter Bezel, so apparently the information that the Dakota Digital system is receiving is information that would normally go to the BCM . . .

There are a few of these "kits" listed on the Internet to enable this using the CANBUS, where people are charging anywhere from $240-$325 for what seems to be one or two standard relays, some wiring and some loom, and considering the prices of the parts involved, that seems to be EXTREMELY excessive, so I thought I would see if I could just create my own . . .

My question is this: Does anyone have a wiring diagram that would allow me to configure a switch or relay to activate the Reverse lights when the transmission is shifted into the Reverse range on the shifter?

LSswap

In your research, have you found out what the CAN messages are for "Reverse"? If so it's possible to build your own relay box using an arduino nano, a relay, a CANbus transceiver board, all for under $50.

If you have the CAN message info, I can help you with sample wiring and software.

stonecoldtx

No, I haven't found that out, but apparently the Dakota Digital module has the ability to determine that, since it displays each of the gear selections correctly . . . is there something I can plug in to the OBD-II port that can obtain that information?

LSswap

This thread has some additional info on the GM messages.
https://ls1tech.com/forums/pcm-diagn...formation.html

Here is a thread I put together for reading Holley CANbus info.
https://ls1tech.com/forums/pcm-diagn...y-can-bus.html

You can try to adapt the diagram and code in my thread to apply to the GM messages and CANbus specs.

stonecoldtx

Thanks, I'll check out these threads and see where they take me!

stonecoldtx

From that first link you provided, there is a post that has this information:

1F5 Byte 4 Shift Position PRNDL 1=Park, 2=Reverse, 3=Neutral, 4=Drive, 9=Low & M1, 8=M2, 7=M3, 6-M4, 5=M5, 4=M6, Byte 6 is Tow/Haul Status 4=ON, 0=OFF. This set changes when in Manual Mode to 2 & 6.

His post says that this is not verified, but I am inclined to think that it's probably accurate

For Fords, there is a software application that can read this stuff, called, "ForSCAN", and lots of Ford owners use it to manipulate certain settings in the various computers . . . For Dodge, there is AlfaOBD, and it also can be used to manipulate certain settings, but the main point is that both of these software applications can read dynamic data from the OBD-II port . . . I would think that Torque probably can as well, so once I use something to determine the CAN message, would the stuff in your second post allow me to create a method of triggering the reverse lights?

LSswap

The stuff in the second post is the framework for how to read the canbus data. It would need to be adjusted for the GM CANbus and you would need to add some if statement that checks if the CAN message says the gear is reverse, then turn on the output that ends up driving the reverse light. You would need to add mosfet (very simple) to drive the lights directly or to drive a relay for the lights. I can add that to the diagram is you wish.

stonecoldtx

I found a place online that is creating a kit for me that includes both functions--reverse lights and A/C request, and while it is a little expensive, I should have it before the weekend, and can move forward with all the other wiring I have in front of me . . .

I appreciate your posts, and maybe I'll continue to explore after I get more done on the car, but right now, this is one of the parts that is holding up my progress, and I really don't have the luxury to spend that amount of time learning the stuff needed to create my own at the moment.

LSswap

That's cool. At least you learned some stuff along the way.