1991 Ls400 Alarm / Remote Key / Trunk Key Help

[jhussain]

I just bought a 1991 LS400 from one of my friends. He had only one key. It has remote button but did not work, so I replaced the battery. Still does not work. The other rhing is that I can mot open the trunk from inside becyase it is locked by the key and the inside swith lever does not open it. I tried to use the key I have but it does not do anything. Third the Security lite is off.

Please give me any hits to fix these problems.

Thanks,

[1990LS400]

The very first thing to do is to inspect the wiring in the left trunk hinge to see if any of the wires have broken. Generally one particular wire breaks first (causing transmission shifting issues) but I saw a report on the ClubLexus forum last week about three wires in the hinge being broken and causing all sorts of weird problems. Do an advanced search for "hinge" in the LS forum for more information on how to fix by splicing in new wire.

Other issues can cause the keyless entry to not work but lets try the above first.

If the inside trunk release lever can not be unlocked by the key, you may have to do a bit of disassembly. Can the ignition key be used to lock and unlock the doors and glove compartment?

[jhussain]

The very first thing to do is to inspect the wiring in the left trunk hinge to see if any of the wires have broken. Generally one particular wire breaks first (causing transmission shifting issues) but I saw a report on the ClubLexus forum last week about three wires in the hinge being broken and causing all sorts of weird problems. Do an advanced search for "hinge" in the LS forum for more information on how to fix by splicing in new wire.

Other issues can cause the keyless entry to not work but lets try the above first.

If the inside trunk release lever can not be unlocked by the key, you may have to do a bit of disassembly. Can the ignition key be used to lock and unlock the doors and glove compartment?

I can lock and unlock the trunk by the key which also locks and unlocks the door and to start the car.

What I want to know is why this key can not unlock the lock locataed under the instrument panel which locks or inlocke the lever lext to it to open the trunk from inside.

Thanks,

[SKperformance]

Can you open your glove box with the key also?

[90LS400]

Hello,

I experienced a similar problem with the 1990 LS400 I have.

The problem is that the remote receiver that is located in the car is defective. Apparently this is a "known issue" with the 1st GEN LS models.

Someone had a thread about this same thing but I couldn't find it to put the link in.

In my opinion, you have two options:

1. Take it to Lexus and ask them to replace the remote receiver. This is going to set you back $500+ but you will be able to use the "original" key.
   
2. Buy an aftermarket Alarm / Remote Key / Trunk package for approximately $200 - $250 installed. In my case, I found a Viper system at Best Buy and had them put it in. This gave me Remote Start, Alarm, Remote Key, & Remote Trunk Release. For my situation, it just seems like a better deal since I didn't really care about using the original key and got the Remote Start capability also.
   

Hope that helps...

[1990LS400]

Here is a thread with information on what ylekiot1 did to fix the keyless entry problem on the 1990 LS he bought from me in 2003: http://us.lexusownersclub.com/forums/index...ic=2188&hl=

As far as the early keyless entry being defective, it was prone to interference problems from other wireless devices. I could never get the keyless entry to work near the grocery store where we shopped.

We take keyless entry for granted today but it was a very unusual feature in 1990.

[BaxFromNZ]

The first thing you should probably do is check the fuse. On right hand drive cecles it is in a fuse box under the bonnet beside the left hand front wheel arch (or just behind it.) I assume left hand drive vehicles are the same. The fuse you are looking for is "Sec Horn" (which is short for security horn. Replace this first before you delve deeper. Good luck.