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I'm new to the Lexus community (just bought this 1999 GS400 2 weeks ago) and I'm getting ready to do some maintenance on it. After it sitting in my garage overnight after some rainy weather, I've noticed a few electrical issues arise.
1. Putting the key in the ignition no longer illuminates the dash (starting the car it lights up fine) and the steering wheel no longer automatically comes out (or retracts when removing the key).
2. The key fob and the door lock switches no longer do anything (the doors no longer lock automatically).
The car starts up fine, goes into Drive fine, traction control + PWR/SNOW mode work fine and illuminate.
I'm going to be checking for any blown fuses because I suspect a short must have occurred due to moisture perhaps. Does anyone here have any experience with these issues and maybe have some clues as to where I should start?
Two separate issues but I'll try and tackle each one. The power tilt/telescopic motors are prone to fail on the 2GS so you'll either need to clean or replace them. Most of the time the former works with just some rubbing alcohol. The door lock actuators are also a weak spot and there are tons of threads about replacing them. As for the dash, there is a dimmer switch that controls the brightness try that and see if it works.
Two separate issues but I'll try and tackle each one. The power tilt/telescopic motors are prone to fail on the 2GS so you'll either need to clean or replace them. Most of the time the former works with just some rubbing alcohol. The door lock actuators are also a weak spot and there are tons of threads about replacing them. As for the dash, there is a dimmer switch that controls the brightness try that and see if it works.
Hi Kevin,
So I can still adjust the steering wheel tilt and telescope if I use the switch, but the automatic portion of it stopped working. Is it common for all actuators to stop working over night? They all worked fine until last night when it suddenly didn't do anything anymore.
1. Putting the key in the ignition no longer illuminates the dash (starting the car it lights up fine) and the steering wheel no longer automatically comes out (or retracts when removing the key).
2. The key fob and the door lock switches no longer do anything (the doors no longer lock automatically)
1. The ignition switch assembly has a sensor that just identifies if the key is inserted or not... suspect that sensor is bad. Track down the lead, and check continuity with the key in or out. If it's bad, we'll go from there.
2. might be related to 1. Figure out 1, first.
I truly cannot find what the key insertion switch is (part wise), I can't find what that would be called. Unless it would just be the whole ignition switch. Do you guys happen to know?
I truly cannot find what the key insertion switch is (part wise), I can't find what that would be called. Unless it would just be the whole ignition switch. Do you guys happen to know?
Here goes...
When we insert our key, and nothing else, such as turning the key... things happen. The instrument panel lights up, the steering wheel moves, etc. That's because the car know that the key has been inserted.
Digging in to the FSM, it appears this is called the "Key unlock warning switch circuit", which performs this function... "The key unlock warning switch goes on when the ignition key is inserted in the key cylinder and goes off when the ignition key is removed.". It sounds like either the sensor in the cylinder is bad, or the wiring to the BCM is bad... did someone do something wonky with the lock cylinder, like try to install a remote-start?
The body control modules need to know something as simple as... is the key inserted? Believe this is important for programming in a new master key... you can't program one, until you fix this.
The FSM for the '98 GS, on page DI-839, shows the circuit. Here's a snip of the circuit...
And a snip of the lock cylinder, from BE-30:
In short, it appears your BCMs does not know that your key is inserted... which is irrelevant to if you can start the car, or operate the vehicle. And under the right sequence of events, if you run the car, without the key inserted, the keyless remote system is going to get very confused.
You have to figure out if the switch is bad, or if the wiring is bad, for that circuit. Guessing that the connector is unplugged, someone messed up the plug, the sensor is bad, or the wiring is bad.
Thank you so much for all of that information! I really appreciate it!
So, I have no information whether a remote system was ever attempted to be installed, I see no signs of that and the previous owner never mentioned it.
I'm not sure if you guys believe it, but this seriously happened over night, nothing changed, I simply drove the car home (it worked fine that night), ans parked it in my garage. In the morning I came out, put the key in the ignition, and the steering wheel did not move, nor did the dash light up.
Things to note: it was raining and very humid out.
Prior to that, my door locks suddenly lost function (Key fob no longer can lock or unlock all doors, and the door unlock/lock switch on the door itself no longer worked).
I will be spending quite a bit of time figuring out what happened, and frankly I'm really not sure how to go about this (I'm learning all of this as I go, consider it my first electrical experience when it comes to vehicles).
Does the Key Insert Warning Switch ground, when the key is inserted?
From SR-14:
And here's BE-32:
DI-839 is already displayed.
Best guess... the Key Unlock Warning Switch is bad. Won't know, until you test continuity when the switch activated. Put the key in, and test pins 1 and 2 for continuity.
05-01-19, 08:34 AM
GS400 Electrical Problems
