Another VATS/BCM question
01-18-2012, 02:49 PM
#1
Another VATS/BCM question This is for a 99 z28 with M6. My security light came on several days ago. It's not blinking, just staying on. Car always starts. Measured the key resistance and it looks to be the 7500 value for my BCM (my keys are 7380 and 7450). Just did the VATS bypass with two different resistance set ups. The first is valued at 7300, which may be too low. The second is 7620. I understand that there is a 2% range around the BCM value (which equates to ~ 150 ohms, or a range of 7350 - 7650).
With the 7300 resistance, the Security light did not go out (but car started). With the 7620, I got the same result - Security light did not go out, and the car started. While the 7300 is outside the range, the 7620 is in the range (but maybe too close to the outer range). I'm thinking of adding ~ 220 ohm to the 7300 version to get closer to the actual 7500 value. Or, might the BCM be the problem?
Anyone had their BCM fail? If so, is this a symptom you experienced?
... and its just a great experience stuffing my 61 year old body under the dash (almost as much fun as changing #8 spark plug).
With the 7300 resistance, the Security light did not go out (but car started). With the 7620, I got the same result - Security light did not go out, and the car started. While the 7300 is outside the range, the 7620 is in the range (but maybe too close to the outer range). I'm thinking of adding ~ 220 ohm to the 7300 version to get closer to the actual 7500 value. Or, might the BCM be the problem?
Anyone had their BCM fail? If so, is this a symptom you experienced?
... and its just a great experience stuffing my 61 year old body under the dash (almost as much fun as changing #8 spark plug).
01-19-2012, 11:30 AM
#2
After doing some research, I see most people that experience BCM problems are mostly associated with their radio and power windows intermittently working, having little to do with VATS. I have new resistance set at 7550 that I'm going to try shortly to see how it works out.
01-19-2012, 02:09 PM
#3
Problem resolved. I decided to keep the the wiring intact in the event that I eventually replace the ignition switch, so I cut the wires from the ignition switch and connected the resistors to the ignitions-side plug and connected it. Below is a photo of the plug and the resistors. Once I started the car, the security light went out after about 10 seconds. After shutting down and restarting, the security light went out right after startup, like usual.
http://i944.photobucket.com/albums/a...9/DSCF0568.jpg
http://i944.photobucket.com/albums/a...9/DSCF0568.jpg
01-20-2012, 08:24 AM
#4
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Could this also be applied if the security light is blinking instead of staying solid..damn car left me stranded last night and no matter what I tried, it wouldnt start. TIA
02-08-2012, 04:24 PM
#6
sorry to be late getting back to folks, but I haven't been on the site for several weeks.
first question: "Could this also be applied if the security light is blinking instead of staying solid..damn car left me stranded last night and no matter what I tried, it wouldnt start." TIA
I don't see why not - it provides the resistance that is expected by VATS.
second question: "What resistors did you end up using xny1989?"
I went to radio shack and picked up several packs of resistors, but I forget which ones. The bottom line is that they need to add up to the resistance of your key. Putting the resistors in series, you add them up. Putting them in parallel, actually cuts the resistance in 1/2. I think I used a combination of series and parallel resistors to meet my need.
first question: "Could this also be applied if the security light is blinking instead of staying solid..damn car left me stranded last night and no matter what I tried, it wouldnt start." TIA
I don't see why not - it provides the resistance that is expected by VATS.
second question: "What resistors did you end up using xny1989?"
I went to radio shack and picked up several packs of resistors, but I forget which ones. The bottom line is that they need to add up to the resistance of your key. Putting the resistors in series, you add them up. Putting them in parallel, actually cuts the resistance in 1/2. I think I used a combination of series and parallel resistors to meet my need.
02-09-2012, 09:43 PM
#7
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ok i am having the same problem. I have a 4750 key and i got a 4.7k resistor i installed in the back of the connector to just test and the car would start but still had security light. so at this time i tried something new... i checked ohms with connector on vats/bcm side with no resistor and got 6440ohms. this confused me i would think i should have got 0ohms with it disconnected and so then i checked it with my resistor in and still got 6440 ohms WTF!!! i removed the resistor and checked it and am getting 4650 ohms.HELPPP i just want this stupid light out and sometime it wont let me start the car for the 4min
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02-10-2012, 04:05 AM
#8
You don't need to check the ignition for the resistance you should just check the key. It took a minute or two for the security light to turn off when I did it. Just be sure the resistor is firmly in the back of the connector, I had to fiddle with it quite a few times to get it all the way in
02-10-2012, 08:42 AM
#10
Yeah, I remember that it did take a little time for the light to eventually go out. The resistance MUST be checked on the key - that is what is transferred to VATS. The problem is usually that the wire(s) from the ignition switch which "reads" the key resistance is broken. I didn't feel like messing with removing the steering wheel with the airbag to replace the ignition switch.
06-02-2012, 10:56 AM
#12
06-02-2012, 02:52 PM
#13
also ive dont my vats delete successfully befoer on my old TA.
this one i have now wont let the light out.its never given me any problems.
i just cant get the light out.ive put the right resisor in twice.triple checked the continuity.i know its making contact.i can see it touching in the back of the connector,but security light is still on.damn it.
