The Security light is controlled by the Theft Deterrent Module.

The Theft Deterrent Module appears to be working.

The Pass Key Decoder module needs power from two sources.

1) 12 volts from the Theft Fuse which you said the fuse looks good. With your meter set to read DC volts you should read 12 volts on both sides of the Theft Fuse. The Fuse is hot at all times.
(Black meter probe to ground, Red meter probe to the fuse).

2) At the fuse panel on the passenger side of the dash, you should read 12 volts on both sides of the Pass Key fuse with the ignition On.

 

Oh, OK - I see now...yes, both sides of installed fuse show 12v...

I don't have a Pass Key fuse...(see pic on previous page)...

 

With the fuse in you should read 12 volts on either side.



I'll have to check the 86 manual. I was looking at a 89 manual.

 

I didn't know you could read voltage/continuity with the fuse installed...

learn something new every day...

 

With the fuse installed if you measure 12 volts on one side of the fuse and no 12 volts on the other side of the fuse it would indicate the fuse is bad/blown/open.

Measure the Vats fuse passenger side of the dash with the fuse installed, ignition On.

If you look at the fuse, there are two test points on the top of the fuse you can touch your probe to. Measure each test point.

 

With ign On, I get 12v on each side of VATS fuse...

 

I sent you a PM.
It appears the Forum is having strange problems.

 

I was able to talk to HookedOnVettes and get some more information. Today I checked the 2nd wire on the starter solenoid stud and verified it controlled the blower motor "high" setting.

I also removed & cleaned the fusible link wire leads on the junction stud under the rear of the battery. It didn't help.



Hooked guided me through the process of extracting error codes from the ECM...My ECM is reporting a "46" error code...

Hooked's next suggestion was to get at the VATS decoder module behind the crash pad...somewhere...

So, I started taking the dash apart. The PO has installed a wood veneer kit, so that made things more difficult. Screws were missing, or the wrong size, plastic pieces were broken, etc. I finally got this far -





That was about 6 hours worth of taking things apart. In another thread, a member commented that it took him 8 hours the first time...So I guess I'm pretty much average...

I'll try lying on my back to get the bottom crash pad screws out (I got the top two out)...Not sure what after that, as the forum threads and the manual are pretty vague as to what to take off then...

Also not sure how to check the VATS module to see if it's working correctly...or where to find a new one if it isn't...

 

Update:

I disconnected the small two wire harness coming down the
steering column from the ignition key lock cylinder and measured the
resistance of the key pellet while it was in the ignition; it measures the same as my key resistance.

I was able to pry the breadbox out enough to get in there and measure stuff.



Here's my readings -

Black VATS decoder connector wire to grnd - .3 ohms (multimeter red to blk test leads = .1/.2 ohms; so this is close to 0) - using TPI manifold as grnd

Key on, neutral safety switch jumpered -

Pink harness lead = 11.5v

Purple harness lead = 5v

All others read 0v

This pic is a connector under the steering column that also goes up to the steering wheel; it has a bayonet connector that plugs into it. I have no idea what it's for, but I cut the twist out and solder-spliced the wire together.



Tried cleaning the edge-connector contacts and replacing module. Still no cranking...

 

(Note: My Web PC took a dump; haven't been able to get on this Forum for a while - finally got a spare PC set up)

All Righty!!!

My Vette is now running and back on the road!!!



The defective part was the VATS Decoder module, that part behind the passenger dash pad [crash pad; breadbox]. You have to disassemble the center console, instrument fascia, DIC fascia, and dash cover to get at it (as shown in post above). These are hard to find, but if you get the part number off the back you can find them...eventually...(some parts suppliers listed below)...

Note: there is also a VATS Theft Deterrent Alarm Module in almost the same location that looks exactly like the Decoder Module. The only difference is the edge connector.



While waiting for the "new" module to come in, I ordered a Baker GM VATS Bypass Module and installed it just to get the Vette rolling and NYS Inspected. (Had to jumper the Starter Enable Relay connector as well). A temporary "fix".

The module I eventually got was an unknown resistance module; I bought the 15 piece resistor pack for under $3 and jury-rigged a setup to test the individual resistors to the module until I found the right one. Then I ordered a blank key (Ecklers, Mid America, etc) and had my local locksmith cut it for my ign switch (using my old key). Worked out great!

I also modified my module wiring to accept either the bypass module or the GM decoder module. M&F spade connectors; pic here somewhere...I'll post it when I find it...

A special Thank You! to Tom [HookedOnVettes], GIJoe, and Brian [vtvette] for their help!!!

A couple of useful Vette parts suppliers, hard to find parts, tools -

VATS Sucks http://www.joestradingpost.com/vats/

JnJ Vette Parts http://home.earthlink.net/~jnjvette/

Corvette Parts Man http://corvettepartsman.com/

vettepros.usa on eBay http://stores.ebay.com/vettepros-usa

Baker Electronix/GM VATS Bypass Module http://www.bakerelectronix.com/products_vats/

652T GM VATS Bypass Kit [set of the 15 resistors used by GM passkeys] Amazon/Search

 

nice to see you solved the problem.
How do you connect the bakerelectronix bypass? Its easy??

 

It must be easy...I'm an electronics dummy, and I got it right the first time...

Baker includes an instruction sheet with the module.