1999 Ls Remote Key Won't Unlock Door

[carminev88]

The remote key for my 1999 LS400 suddenly stopped unlocking the doors. It will lock the doors and it will open the trunk. I've changed the batteries in both the keys I have and they both do the same; lock doors and open trunk. Any suggestions?

[1990LS400]

Does the lock/unlock switch on the inside of the drivers door still lock the doors?

[carminev88]

Yes, the switch on the driver's door works fine.

[billydpowell]

bad news, I am afraid you will have to go into the door to see what broke, there are some small clips in there that hold the rods.

[landar]

Yes, the switch on the driver's door works fine.

Assuming that you mean the electric switch works fine then that would clear the physical locking mechanisms. And obviously a radio signal is being emitted from the remote. I wonder if some anti-theft system is confused and blocking a remote unlock. Maybe disconnect the car battery overnight and see if that clears? Agreed, it is a shot in the dark. Are these the remotes that originally came with the car?

[carminev88]

Both the keys are the originals and both will remotely open the trunk and both will romotely lock the doors. The switch on the driver's door panel will lock and unlock all of the doors. I don't think it is a problem with the locking mechanism. Does any know where the circuit board for the remote is located? Since it suddenly stopped working, I have to agree with Guru member that it is a signal or security system problem. Any information is appreciated!

[billydpowell]

disregard previous post, misunderstood, there is a small circuit board in the key head. I do not know what it is completely, but part of it could be your problem. I have changed them out when getting a new key made. if everything is working but that one button on that one key, well you either need Lexus or a new key with the transponder in it... keep us posted if you choose to conquer this.

[carminev88]

Since I've used two different (original) keys and neither work, so I can't imagine the problem being with the key. I tried disconnecting the battery for two hours, but no change. I few days ago, I tried to open the door with the remote (as I do everyday) and it responded, but only that one time. My best guess is that either the receiver in the car has gone bad or it has a bad connection. Several months ago I swerved to miss a large metal tool box in the road and hit the curb hard enough to bend a wheel. That makes me wonder if the circuit board might have been knocked loose.

Does anyone know where the receiver is located?

Carmine

[landar]

I believe the receiver unit is located inside the trunk, left side(drivers). There are panels that need removing.

[1990LS400]

The attached diagram for the 99 LS400 shows the receiver somewhere under the dash but it certainly doesn't show exactly where. The receiver was in the trunk on the early LS400.

[landar]

From that diagram, it looks like it is right behind the glove box. I can't seem to get the ToyoDIY site to give me diagrams even though I registered.

[carminev88]

Thanks for the help! I've been working 12 hour days and haven't had time until now to check it out.