Positive/Negative Door Locks Interfere With BCM

Hello! I am installing an alarm system in my vehicle. it is a Dodge / Chrysler vehicle. It uses a 12v(+) signal for Unlock and a 12v(-) signal for lock (I guess this is a reverse polarity system?) There are 4 wires going to each door lock motor assembly. 1). Ground Wire 2). PCI Bus Wire 3). Wire to side A of Door Lock Motor 4). Wire to side B of Door Lock Motor I don't "think" there's a negative or positive wire per se...I "think" it just carries the 12v pulse from the BCM across the two wires in a reversed polarity depending on whether you push the Lock or Unlock buttons. So, for example to Lock the door, the pulse travels one direction and when an Unlock is sent, it goes the other way...or reverses. Like having a DC motor connected to a 12v DC battery....and switching the wires to the opposite terminals. Anyway, it works great...UNTIL I plug the BCM connector back into the BCM at which point fuses are blown upon locking / unlocking (not sure which blows the fuse) and the locks no longer work. So there is definitely a cross polarity issue going on. Problem is, I don't know how to correct it since if I put blocking diodes inline on the alarm wires, it blocks either the inbound signal when using the remote or it blocks the outgoing signal. So it seems it needs a blocking diode, but you can't use one as it will block either the BCM function or the installed alarm remote function (my choice which). The alarm has jumpers that allow you to select negative trigger door locks or Positive trigger...but neither works. I can supply wiring diagrams and wire color codes, specific year and model of vehicle if all that would help. Thanks for any replies (hoping).

Unless I'm having a unique issue with my vehicle, I surprised this hasn't been an issue for other installers? Installing a reverse current/voltage door locking system that can work in unison with the factory locking system is a bit more complex than just connecting alarm wires (I think). With reverse current locking systems (as with many Dodge / Chrysler vehicles it gets more complicated. I'm mapping out the components and their connections and the switching needed but it's complicated. I'll post the mapping when I figure out exactly what works. There may be some diodes involved but I'm not sure yet.