Vehicle: 1995 XJ12

We are engine swapping from the V12 to an LT1. We can not seem to get fire to the starter wire coming from the starter relay. The P at the shifter is glowing red, and the key is being read by the system. Every system on the jag is working except for the starting system. We have tried to bypass the body processing module by wiring a switch from the red/white to the red/orange wires, with no impact. Directly grounding the starter relay also seems to do nothing. There is no transmission in the car at the moment and there is a transmission light on, and I was wondering if that would have an impact on the starting system. If not, any help is appreciated. Side note: every fuse in the entire car is good, and every relay on the starting system has been tested. Thanks in advance.

 

are you using the x300 electrical guide

you need input from the trans rotary/safety switch

 

Or in the case of the V12 starting system, input from the Linear switch (black box at the side of the shifter). That would be a ground input on the Red/Blue wire from the Linear switch to the BPM. Same input as from the X300 six rotary switch.

Also needed is the Check Engine ground input on the Light Green/Black wire from the ECM to the BPM.

Orange and Pink wires at the BPM are serial communication wires. They connect most of the modules. Without a transmission in the car, the BPM might disable starting.

 

The V12 in the factory configuration with the GM transmission does not use a transmission mounted rotary switch for a starter enable signal to the BCM

The BCM once it receives the different enable signals from different areas provides a ground to close the starter solenoid relay

One of the enables you would be missing is the engine ECU since you are not using the V12 ECU

You can find a way to have the X305 ignition switch provide a control ground to a starter solenoid relay and bypass the need to go through the X305 BCM

But this removes the safety feature of your transmission being in park and security module disable



Pin 5 is the car frame ground path on the car side of the connector and the 1 pin on the switch side of the connector is a spring loaded return to open contact to close a proposed straight starter solenoid relay

The connector is to the left side of the steering column and the car side of the connector lifts straight up to remove it from the dash mounting to bring it out to you to work with easier


This is how you remove the key barrel which you don;t have to do , the ignition switch detaches from the key barrel with the barrel still installed



Pic comming