hey guys just trying to button up some things on the truck before the pull this weekend and i need a neutral safety light, where should i hook this into? i have the kill switch done but i am unsure how to do this and really don't want to mess the truck up thanks.
Neutral safety light?
- Thread starter mmasuperman12
- Start date
Gonna bump this up. I was also wondering where people hook up a neutral light. Any insight would be appreciated!
I would have to find a schematic for the wiring but you may be able to tie it into the shift indicator on the dash. When it goes into neutral on the indicator you may be able to run a power wire off of that to a light on the back of the truck but I'm not sure how they are lighting that indicator up on the dash exactly.
Thats what I was thinking as well. Im sure there has to be a wire I can just tap into and do like you said, just run it to the back of the truck. Someone has got to know which wire to hook into.
micro switch on lever on trans that activates when you're in the park position. It's technically in N with the parking pawl engaged.
I would post the question in Mike L's forum or even contact Ben from BT Dieselworks. Both have a pretty good understanding of the electronics. I would assume it's tied into the NSBU switch but it may be resistance vs. a dedicated nuetral signal (at least that's the way it works on my Dakota Digital dash in my gasser).
You'll probably get what your looking for much faster posting this in the trans section.
OR as stated you could do an independent system with a microswitch which would lessen the chance of screwing something up in the harness or electronics of the Allison.
You'll probably get what your looking for much faster posting this in the trans section.
OR as stated you could do an independent system with a microswitch which would lessen the chance of screwing something up in the harness or electronics of the Allison.
anyone ever figure anything out with a light? im trying to figure it out now and having a hard time finding anything... :dontknow:
On the 2006+ trucks, its a lot different and more difficult to wire up a neutral safety light. Because the NSBU is inside the trans (IMS), things are wired a lot differently from the 01-05 trucks.
Park/neutral information is all over the databus, not discrete 12v wires.
There is an output on the BCM that supplies +12v only when the trans is in park (its to actuate the brake/shifter interlock solenoid). When the trans is in park, the TCM sends a data message to the BCM, and the BCM turns this output ON. BCM connector C2, pin position A1.
This output is only on in park though, its off in reverse, neutral, drive, and M.
There is a park/neutral signal wire going from the NSBU to the ECM, but its not a +12v ouput. Its a "grounded when in park/neutral" wire. Whether you can wire that up to a light (IE, put +12v on one side of the light, and then tap the - side of the light to that park/neutral signal wire), I dont know. It depends on the internal circuit structure/schematics of the ECM. If its a 5v reference signal with an internal pullup resistor to +5v, then it will cause problems and might even fry that digital input on the ECM. If its +12v reference, then it should work fine.
The only way to tell, short of taking the ECM apart, is to disconnect that park/neutral signal wire from everything (IE, make sure the trans connector and TCM is unplugged) so the signal wire is "floating", turn the key on, engine off, and use a volt meter on that wire and see if the ECM is pulling the signal wire up to +5v ref or +12v ref.
ben
Park/neutral information is all over the databus, not discrete 12v wires.
There is an output on the BCM that supplies +12v only when the trans is in park (its to actuate the brake/shifter interlock solenoid). When the trans is in park, the TCM sends a data message to the BCM, and the BCM turns this output ON. BCM connector C2, pin position A1.
This output is only on in park though, its off in reverse, neutral, drive, and M.
There is a park/neutral signal wire going from the NSBU to the ECM, but its not a +12v ouput. Its a "grounded when in park/neutral" wire. Whether you can wire that up to a light (IE, put +12v on one side of the light, and then tap the - side of the light to that park/neutral signal wire), I dont know. It depends on the internal circuit structure/schematics of the ECM. If its a 5v reference signal with an internal pullup resistor to +5v, then it will cause problems and might even fry that digital input on the ECM. If its +12v reference, then it should work fine.
The only way to tell, short of taking the ECM apart, is to disconnect that park/neutral signal wire from everything (IE, make sure the trans connector and TCM is unplugged) so the signal wire is "floating", turn the key on, engine off, and use a volt meter on that wire and see if the ECM is pulling the signal wire up to +5v ref or +12v ref.
ben
Any update on this?? Does anyone know if bens suggested wire will work ? Or is it a signal wire?
I'd say you could probe the wire with a multimeter with someone selecting gears to figure out the voltage
You could tap into that wire and use a diode to prevent +12v from backfeeding to the ECM.
Basically, cut the park/neutral signal wire that goes from the NSBU to the ECM. Then put a diode inline with that wire. Cathode (stripe side) on the "transmission" side of the wire. Any 1n4001/1n4004 diode will work, you can find them at radio shack.
Then "T" the ground side of your light into the park neutral signal wire "after" the diode, on the transmission side of the diode. Then hook up the + side of your light to +12volts.
That will prevent current from backfeeding to the ECM, while still allowing current to flow from the ECM's own internal 5v pullup reference to ground when the trans is in park/neutral.
ECM_____[diode >l ]______[lightbulb]____ +12v ignition
....................................l
....................................l_______________[trans NSBU]
Ben
Basically, cut the park/neutral signal wire that goes from the NSBU to the ECM. Then put a diode inline with that wire. Cathode (stripe side) on the "transmission" side of the wire. Any 1n4001/1n4004 diode will work, you can find them at radio shack.
Then "T" the ground side of your light into the park neutral signal wire "after" the diode, on the transmission side of the diode. Then hook up the + side of your light to +12volts.
That will prevent current from backfeeding to the ECM, while still allowing current to flow from the ECM's own internal 5v pullup reference to ground when the trans is in park/neutral.
ECM_____[diode >l ]______[lightbulb]____ +12v ignition
....................................l
....................................l_______________[trans NSBU]
Ben
Now on a Lly we are talking about the orange and black wire that goes into the nsbu correct Ben? Also while we are on the subject of wires Ben, which wire can I tap into either on your lock box or elsewhere that I can wire in a larger light to visually make sure the converter is locking? Need a light other than the green one on the box.
You can "T" into the black wire going into the lockup controller connector. NOT the black/white-stripe wire (ground)...the solid black wire that goes out to the TCM.
If you use a 12v LED or bulb, and splice the (-) side of the bulb to that black wire, and then the (+) side of the bulb to ignition +12v, that should work well for giving you a lockup LED.
That will light up when the box is force-locking the TC, as well as when the TCM locks it in normal daily driving/standby mode.
Ben