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I need to locate the factory ecu for a 1998 Lexus GS 300,

I need to...

I need to locate the factory ecu for a 1998 Lexus GS 300

Mechanic's Assistant: Okay, I'll connect you to the mechanic to go over that information regarding your Lexus GS 300. Before I do, is there anything else you want him to know?

The alarm goes off when the battery terminal is connected

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Answered in 5 minutes by:
9/17/2017
Toyota Service
Toyota Service, Lexus and Toyota expert
Category: Lexus
Satisfied Customers: 5,239
Experience: 30 + years of experience; Multiple Award Winning Svc Mgr; Just Answer Customer's Choice Award Winner
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Hello. Welcome to Just Answer. Please allow me to assist you. Please clarify the problem with the car. Was the battery dead or replaced that causes the alarm to go off when connected?

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Customer reply replied 11 months ago
No the battery wasn't dead or replaced . I've been having issues with the alarm for awhile now not locking the doors etc. now it goes off when trying to start the car. All doors are locked and the trunk as well
Customer reply replied 11 months ago
I'm probably going to get a aftermarket alarm but for now I need to disable it

The factory alarm control unit is either under the driver seat or on the under the extreme left (driver) side of the instrument panel (depending if it was factory installed, port installed ot dealer installed); could be in either place.

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Customer reply replied 11 months ago
Do you have a photo of what I'm looking for I don't want to disconnect the wrong item. When disconnected will I have any other issues with the car
Customer reply replied 11 months ago
Pretty sure factory installed

If you are having problems with the factory unit, it needs to be completely removed from the car. If you disconnect the control box the car will never start, because the box wire harness splices into the wire harness (via wire connectors) for the ignition switch. The best thing to do here is remove the lower instrument trim panel (above the driver knees) and locate ignition switch wire harness. There you will find a wire connector and harness. Follow that harness backwards, moving away from the ignition switch. As you move back, you will find the dash harness. This will plug into the ignition switch connector socket. The factory alarm box is a small black box; flat, about 6 inches square. Once you locate it, follow all of the wires and disconnect them, finding a similar socket that the alarm harness plugs into. The harness for the alarm interfaces with the dash harness. It is not super easy to disconnect, but can be daunting if you are not familiar with what sockets need to be reconnected. If you have any reservations about this, I recommend you tow the car to a dealer. Splicing the wrong wires could short out the body computer; that would be a very expensive replacement cost.

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Customer reply replied 11 months ago
34; follow all the wires and disconnect them" is there a wire i need to disconnect the will bypass the alarm and allow the car to function without it in place? The closest dealer is about 60 miles away and for a 1998 with 256k miles I'm trying not to spend 2k for this fix the car is worth about that.

There is no single wire you can disconnect to render the system inoperative. The alarm is wired into the ignition and the engine control system. It will not take 2k to remove the system. Maybe 200 dollars tops.

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Customer reply replied 11 months ago
Ok thanks

You are very welcome.

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Toyota Service
Toyota Service, Lexus and Toyota expert
Category: Lexus
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