2000 Buick LeSabre security light.

[jturne]

For a year I have been unable to fix, even though the dealer put in two computer modules and an entire fuse box and new battery under the back seat. The problem: Car appears to be totally dead until I slam the trunk lid once. It then starts and all is well until the security light comes on and the radio, a/c, gas guage goes off. Intermittently, it may come back on but the security light still glows and the problem keeps repeating. HELP! Is it a trunk lid security sensor? If so, how do I eliminate it?
thanks, jturne

[pcmos]

It's going to be very difficult to track down for sure until you get hold of the trouble codes that are stored when the problem occurs. If you have you're invoices from the past repairs can you look to see exactly which of the many computer modules were replaced?

There are two modules located in the trunk area, under the rear shelf on the inside of the trunk. One module is the rear integration module, the other is the remote function receiver module. I would want to make sure all of the connectors on both modules are firmly attached. The system could be losing the data link connection someplace in the loop and its certainly easy enough to start by checking the connectors on those modules. I would think if the problem were the trunk switch, then when it acted up with the vehicle operational it would just say "trunk ajar."

FYI: according to the shop manual if the security light illuminates while the vehicle is running, then it is absolutely indicating a trouble code for either the CTD (content theft deterrent) or VTD (vehicle theft deterrent) system. That means if you get the security light while you're driving, then there almost certainly is a trouble code stored, unfortunately the OBD II scan tools will not read that code, you have to ask the dealer to retrieve them for you using the Tech 2 scan tool they have.

[ponchonutty]

I had a dealer call me with a simular problem. This one had half of the gauges work when it wouldn't start. If you slammed the tilt steering up or down then tried to start it many times it'd be OK. Ended up being a short inside the instrument cluster. Replace the cluster and it was OK.