I hadn't looked at the ECU /wheel speed box connection too closely. I would have to have an understanding of the signal passing through that wire to know how that half of the switch works. The mod he posted was a diagram from some other forum he added the locker switching modification according to his post. Now just looking at that side of the switch from a logic standpoint without defining the signal travelling on the purple with light blue tracer wire, if that is normally connected without the switch, then it would make sense that disconnecting it would modify the signal and prevent the ESP from activating (I'm speculating). If that is the case, then you would want that open when the lockers are forced to the locked position. That would actually require a double pole double throw swtich DPDT. With the double pole single throw switch DPST that he has depicted, it looks like the ESP would be off while the lockers are not being forced to lock and ESP on with the lockers locked.
Originally Posted by Codeman911
Jk'n, lookin at that diagram I wonder why you would have to tie into the ecu and the wheel speed box? Couldn't you just run a wire to the relays like you have shown and then hook you toggle to a power wire that's hot with key on so any time you flip the switch they lock?
Now to answer your question about running a wire from hot to the relay, please observe the way the the circuit is currently wired. The top of the relay coils for both lockers and the common of the relay contacts on both lockers are wired to the line that looks like it is labelled S152 (it is blurry) if you follow that line up it goes through a 25 amp fuse to hot so the top side of both relay coils is positive 12V. The bottom of the relay coil if grounded, will activate the coil and thus the contacts would operate and the lockers will lock. The output of the module on pins 41 and 42 are known as current syncing outputs. When an input causes the output to activate, it basically brings the output to ground otherwise the output is "hi z" or not connected to ground or floating. Without putting the diodes in there as I had shown in my modification of his diagram, because pins 41 and 42 are connected by a wire in his diagram, either output syncing to ground will cause both relays to activate with the switch in the off position (open switch). This would not allow the circuit to operate as the factory wiring intended it to with the switch in the off position. The factory wiring allows the rears only locked or both front and rear locked. With the diodes in there, either output can be low without effecting the other output while the switch is off. When the switch is on both outputs would be synced to ground through the diodes and both lockers would lock regardless of the condition of the outputs on pins 41 and 42.
I'm pretty sure that you would want to make the other side of the switch to be open when the lockers are forced on and closed when the lockers are not forced on. So basically when the locker side of the switch is open, the ESP side should be closed. and when the locker side is closed forcing lock, the other side should be open preventing ESP from coming on. Again, that would require a double pole double throw type switch that has two positions on/on, they do make a three position switch on/off/on. On the three position switch, the common is not connected to either side when in the center position and that would not be required in this application.
Now, I hope I haven't totally confused you. :)