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Tutorial: Remove Is200 Roof Lining And Fix Alarm Problem

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So for the last few month I have been having problems with my 99' Lexus IS200. It seems that there was a problem with the alarm that has been setting is off at all hours of the morning. The only way I found around it was to leave my car unlocked over night, which wasn't very comforting. So I was reading around the forums for a fix but I couldn't find a clear solution for it. I found that it may be the motion sensor that was causing the problem but I couldn't find out if it could be disabled or how to disable it, so I went hunting.

I decided that I would remove the roof lining and heat shrink all the wires as this may have been the problem. After pulling my entire roof apart I found that the motion sensor itself was inside the dome light and that it was as simple as unscrewing 3 screws and disconnecting a single harness. So if you are having the same problem try disconnecting it before you go ahead and waste a lot of time haha. I have only just disconnected the sensor so I'm not 100% sure if it is the problem but I'm certain that it is. I will post back in a few days telling you how I go.

Disable motion sensor

Time: 5 minutes

Difficulty: Easy

Motion sensor harness:


The big circle is the motion sensor.

The small circle is the harness to disconnect.

Removing roof lining

Time: 40 minutes

Difficulty: Intermediate

1. Remove the A-pillar by gently pulling.


2. Remove the B-pillar by removing the seat belt cover, unbolt the 14mm seat belt bolt and gently pull the cover off.


3. Remove the C-pillar the same as the A-pillar.


4. Remove the map light by pulling down or prying it.


5. Remove dome light by removing the lens cover and unscrewing the 3 screws.


6. Remove rear-view mirror by prying the cover and removing the 2 screws.


7. Remove the sun visors by removing the 2 screws on the outer side, disconnect the harness and remove the screw holding the pivot point.



8. Remove the grab handles by removing the covers on the end of the handles and unbolt the 2 bolts on either end.


9. Remove the 2 push in clips near the rear window(sorry no pictures)

10. Remove the roof lining. The roof lining should now be completely free. The easiest way I found to get it out is by folding down the passengers seat and removing the liner through the rear passengers door.

I hope this helps anyone who is having the same problem as me. If you have an questions feel free to post of pm me.

If anyone is curious I may weigh some of the part for those wondering about weight stripping

If you would like to see more photos click the link below:


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  • 1 month later...

You dont need to remove the whole roof lining, just the interior dome line housing.

1) remove plastic covering of the light

2) unscrew the 3 mounting screws

3) once the inside is exposed, unscrew the 4 screws holding the sensor and the housing, disconnect the black harness is fine too directly on the sensor.

Alarm was going off all night, and we were wondering who the stupid f00 was LOL. A passer by told us about it.

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  • 4 weeks later...

My car alarm went off for a weekend a couple of months back and ever since then whenever I unlock the car the alarm beeps 10 times. I bought the car second hand and ever since I bought it the main key hasn't worked to unlock/lock the car via remote. I replaced the battery in it and that didn't fix it. When I press buttons on it the little red LED comes on but it doesn't connect with the car. Because the secondary key is less bulky I just use it and leave the main key as a spare at my parents' house.

Tonight the alarm decided to start going and I couldn't manage to turn it off before giving up and disconnecting the battery. Unlocking and locking the driver door didn't do it. Turning the car on didn't do it. Opening the boot didn't do it. I'm keen to just disconnect the battery completely and be done with it as cheaply as possible as I'm a student. What's the easiest way to go about doing that?

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If one key unlocks the car and the other doesn't then that's a pairing issue that lexus should fix for free(I've had it done 3 times for free), if both aren't working then it's mostly the receiver, which is broken on my car and I haven't looked into fixing it.

As your your other issue I have no idea. I've been told that locking the car with the key doesn't activate the alarm but I've been using my key for over a year and it has still gone off, hence this guide.

I would say disconnect the entire alarm but I have no idea how. Have a quick google/forum search and if you find out please post a comment back here :)

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I guess I got my facts a little wrong. I wasn't having problems with my alarm, it was the boot siren. That was really easy to disconnect once I figured out what I was looking for. I disconnected that and haven't heard anything from my car yet so I'm guessing I managed to shut it up.

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