I dunno...I cannot find the alarm module that looks like the decoder. If its behind the defrost duct or hidden, maybe, but its not as obvious or easy as the decoder. Thats right under the bread box.

 

No, not your failed module, but for a newer used one you are replacing it. You asked about in your initial post "How do I find the code"? Interrogating will require you to buy new keys through traditional means. Replacing the resistor on a replacement good module to match the key to me is the cheapest and fastest solution. I do see you are now asking about the theft module too so I am a little confused on what you are trying to accomplish here. If you don't even know where it is why are you attempting to replace it? Tells me the theft module has not been diagnosed and we are blindly troubleshooting this. Perhaps it is me with the misunderstanding so I will gracefully bow out of this thread.

Regards,

 

It's taped to the large wiring harness that goes to the fuse panel, directly behind (as you're sitting in the passenger seat) the VATS module. I think it was originally (pre-'86) mounted where the VATS module is now.

 

Thanks Cliff...
Thats what I was tghinking...hidden behind the panel that the decoder is mounted to. There is the trunk line that is attached there and the harness subsections have all been traced. That area was the last unseen spot to hide something...! I can pull the duct and part of the dash bracket system to access that. Dang chimes is AFU so I need to d/c all those things to clean and replace anyway.

Interesting note on the decoder...
I relocated it where I can get to it from under the IP rt side below. Now when it does its random BS...its a simple matter of unplugging it and reinserting the plug on the board fingers(contact issues perhaps?) and the car will fire right up. I need to re-examine the board for loose joints or cracks...something is loose on that decoder. I'm certain of that much.
As soon as I get some other fires put out, I plan on ripping the interior out AGAIN..for the annual cleaning and cash count. R I'm only expecting to harvest $5 or less...its been a slow year.
Until that time I'll keep doing the research and looking for a spare decoder just in case. I wish I had seen the future coming and been betetr prepared for this...I should have stockpiled C4 electronics like I did brackets and other misc engine/chassis parts back in the day...

Dans85..
I get what you are saying but the point of this exercise is to get back to a fully functional VATS system without jury rigs or bypass. IF I am fortunate enough to locate a good decoder, then I will use a variable resistor to isolate and ID the module code if the resistor color codes in the module don't tell me...and from there I get the correct key cut. It all goes in a box and lifes good again for another 20 yrs... Cliff posted a pic and he has indicated which resistor IS the one in charge of the key code in the decoder.