JTheJackal

Hello there, I appreciate there are a lot of threads on VATS problems and I have looked around but to no avail, so any help would really be appreciated.

I have a '96 Camaro Z28.

Since I bought it (around March), the security light has come on solid and locked me out for 3 minutes at random times, before letting me start the car. This was annoying but I could live with it.

Just over a month ago, the security light came on while I was driving, flashing. When I stopped, the car wouldn't start up again and still hasn't to this day. All electrics come on and I can hear it priming, but the security light just blinks once the keys are turned to on.

As per suggestions, I have measured the resistance from the keys (2370 ohms) and wired in resistors adding up to that value, following instructions from shoebox's website. Nothing changed.

I have located the BCM under the glove compartment but I'm unsure what I'm doing so I wanted confirmation before going ahead:

a) Do I pull the entire plug out before joining the wires?
b) Which wires do I join? On shoebox's website it says to join yellow and purple, but I can't see either.
Edit
c) Should I even do this for a flashing security light?

To summarise the things I have tried:

i) Checked for engine fault codes and there are none.
ii) Wired in resistors behind the vats connector under the steering wheel, adding up to the amount of resistance provided by the keys.

Special complication: I live in Scotland and no auto electricians I can find want to even touch it because they know nothing about them. Even the Chevrolet dealership turned me away.

Cheers.

Injuneer

When you wired in the resistors did you cut the wires coming from the ignition key cylinder? ...or unplug the connector? You need to do one of those:

http://shbox.com/1/vats_bypass.jpg

GaryDoug

Also make sure the resistors total within 5% of the nominal value for your key code number. Some resistors are already 10% tolerance and that can put them out of spec.
4th Gen LT1 F-body Tech Articles

It's not yellow and purple. It's white/black and purple/white. Those go to BCM connector C3, the one closest to the door. But those are the same wires as under the dash.

Do you mean the yellow and purple wires on the theft deterrent relay instead? If you jumper those, it will enable the starter, but will not enable the fuel injectors. You would have to install a VATS bypass signal module on the wire from the BCM to the PCM in order to completely do away with the VATS system.
http://www.bakerelectronix.com/products_vats/

JTheJackal

I cut the wires, yeah.

JTheJackal

Sorry I was talking about the TDR, yeah. Thanks for the info though, I'll forget about that for the moment then.

The resistors are reading a total of 2378 on the multimeter. 2370 from the key.

One of the wires I have the resistors attached to feels a little jiggly in the socket. At the risk of sounding like an idiot, any tips on how to unplug the socket altogether?

GaryDoug

Use a tiny screwdriver as shown in the photo. Are the resistors soldered to the car's wires? If not, you may want to do that. Or use crimp connectors.

JTheJackal

Thanks, I managed to get it off.

The resistors are just sitting on the wires at the moment. I've tried twisting the wire around to make sure they're touching firmly but judging from how firm a connection the multimeter needs for a true reading, you're probably right about soldering or using crimp connectors.

Unfortunately I don't have either so I'll order some connectors just now.

JTheJackal

Update:

I've determined that the resistors are doing their job using a multimeter. So the problem must be further up the wiring, or something else.

I should have noted some (possibly) important points in my original post:

When I turn the keys to ON, there is a notable click noise from the passenger side of the car, at the same time the security light begins flashing.

The car has an aftermarket radio installed by the previous owner. I've tried pulling the fuse after reading wiring faults elsewhere could cause security light problems.

The car battery was faulty so I replaced it about 3 weeks ago.

GaryDoug

Do the other BCM functions work: Interior lamps, hatch release, door opening turns on lamps, seat belt lamp, delayed power for radio and windows, power door locks?

Trace the two wires from the resistors to the BCM to make sure there isn't an after-market module somewhere.

JTheJackal

I can't check until tomorrow to make sure but I'm fairly sure the interior lamps don't come on now. They used to but I don't remember them coming on since this started.

Hatch release never used to work but works now. (Dunno).

The rest work okay.

I'll confirm tomorrow.

JTheJackal

So I've checked. What works:

Interior lamps ("reading lamps" on the rear view mirror) when pressed.
Hatch release.
Delayed power for radio + windows.
Power door locks.
No interior lights come on when the doors open. (edit - checked the fuse and the lights work now).

What doesn't work:

No warning on the dash for open doors or seat belts.


I've followed the wires to the BCM and I can't see anything out of the ordinary.

JTheJackal

Any more advice on this? I'm stumped and google results just returns resistor bypass 99% of the time.

GaryDoug

I see only two possibilities: defective BCM or you are using the wrong key resistance value. You might try connecting the resistors directly to the same wires at the BCM connector. You can probably just stick the two ends of the resistor set into the back of the BCM's connector like I did here for the column connector.

GaryDoug

At this point, here is what I would do: Get a couple of potentiometers and wire them in series so you can dial up any one of the 15 different resistor values. Or buy a kit of the 15 resistors. They are all over eBay. Then test each value on your BCM. You will have to wait 4 minutes between each test. You will probably have to do that if you buy a used BCM anyway unless it comes with the known resistance value. Only a brand new BCM can be programmed to a specific value and only once.

An alternative would be to do a total bypass like I referenced in post #3.

JTheJackal

So after a long time of it sitting in my driveway, I have an update.

It did turn out to be a faulty BCM. I replaced it with a new one today and got the car started up immediately.

Thanks for all the help.