OK I have looked at my rave manual for my 97 and it shows me on my truck that the security module has a 26 pin grey connector on it and the wire is blue/green at pin 8. if this is not pretty close to what you are seeing we should discuss this a little more. it may be a blue wire in the same spot on the same connector

 

No luck I think I will have to replace the ECU, damn!

 

Oh? I was using the blue wire on pin 6. I will give it another go. Thanks again for taking the trouble to help.

 

just out of curiosity what country are you in?

 

US.
Don't take any notice of my pin numbers I just realized I don't know which end is up! Ok I just checked for a blue/green and couldn't find anything that color.

Can you tell me how to orient which pin is which? Perhaps you can tell me, is the pin I need on the row with the red antenna wire or the other row? which end do I count from to get the correct pin number?

 

Is there any way to drive the truck (maybe by bridging out the immobilisation circuit) to go pick up a new ECU?

 

my rave manual does not show a red antenna wire

 

as for bypassing the immobilizer to start the truck yes there is a way but I would need to see the wiring to tell you how to do it on your truck. try to find the wire that goes to the key switch in the drivers door, the US trucks should be able to disarm with that switch. when you find it, tap a quick ground to it

 

Is the drivers door key wire the one you already mentioned that was pin 8, blue/green?
If so i already tapped that to earth but no change.

 

yes I had you tap it at the security module as it could have a weak ground point on the door or a bad/loose connection somewhere in route. did you try tapping it a few times, with the doors all closed? also are any of your switches not working correctly? a faulty door trigger or hood switch could be causing some issues as well.