Need someone with a 95 manual to see how the cluster is linked. I wish Yamae would get on this one. I don't even know what to check or where to start on this one.

 

The cluster gets the DC 12V from the fuse named "10A Meter" via the contact "IG2" which is a part of the ignition switch. I'd check the continuity between the battery and the fuse "10A Meter" first. As I already informed you, there tends to happen a contact problem of the ignition switch when the car gets old. The contact has to handle a big inrush current and the surface of the contact tends to wear out.

 

Yamae, did you watch the video? I would like to know why part of the cluster comes on then there is a delay and the rest of it comes on, and then he can start it?

 

Yamae: I'll check the continuity of the points you indicated. The video was shot with the new ignition switch connected and it behaves in exactly the same way as with the old ignition switch. (This switch is very cumbersome to get to, so "just replace it", isn't as easy as it sounds... )

In my (pdf) manual I cannot find any "Meter" fuse, but there are 10A fuses named "Panel" (Taillight??), "PWR-IG", "GAGUE" and "IGN", all which seems very interesting to check though. Nor could I find the "IG2" contact, but I assume it must be the contact which goes into the ignition switch.

I take it my problems are to be found somewhere in the middle of the attached picture.

Again, thank you for your time and effort. Keep 'em coming.

 

Attached 2 diagrams are from a JDM manual for a 94-97. The term I used "Meter" must be "Gauge" in the wiring diagram you showed me.

The second drawing shows from the fuse to the cluster. There are two junctions. One is "Centre Junction Box" and the other "Junction Box No.3". These two should be checked too.

 

Hi again...
Soon after that I made my last post some 15 months ago, the problem disappeared. I havn't had any problems with the car whatsoever, until yesterday when I was about to start the car after a short spin (in rainy weather). Now the same symptoms were back, but after a few attempts (of twisting the key) the gague needles lit up and the starter motor turned etc. Today I had to go for a bit longer distance and the car died on the highway... This time I was not so lucky, as the car refused to start again.
I also found, while waiting for the tow truck, that the gague needles did lit up when I slowly turned the key between the "radio" and "ignition" positions, but it went black again if I then went back to the "ignition" position.

In the last answer from our hero Yamae, he writes about "Junction Boxes". Where are they located? (On the back of the inside fuse box? Or where???)

 

Sounds like you have some connection issue at a contact of your ignition switch.
Regarding to the Center J/B and the J/B No.3, attached is for a JDM but they are located there shown by the red characters.

 

Thank you Sensei.
Now I know what to look for.

 

Is there a way you can take apart the ignition switch and lube the internals with dielectric grease? I had this issue happen with my blower motor in my old Honda Accord, for the positioning of the vents. It used a copper circuit that a switch slid along. The contacts were getting pretty worn and dirty, so I cleaned it and lubed it with some conductive grease and now its responsive again. Maybe something similar is happening inside the switch with some contacts not energizing because they're dry and need better conductivity between them?

 

The big problem isn't whether the 20+ years old switch can be repaired or not. This switch is rather difficult to get to. There are panels and other stuff in the way, you (probably) have to take out/move the driver seat etc. Then at least one of the two screws holding the switch is very hard to get to. unless you can get the ventilation pipe (the repair manual calls it "No.3 Heater to Register Duct", at least that is what I can work out from the drawings...) from the center of the car out. Once you get the switch out, the safest bet is not to repair it, but to exchange it. (An OEM part is maybe $50 and Lexus/Toyota is say $100.) Anyhow, I'm in the process of geting to the ignition switch right now and will report back on the condition of the switch and how to get to it.

 

Getting to the ignition key switch wasn't that hard after all. The steering column is attached to the "sub-frame" under the instrument panel with 2 17mm nuts. Then the steering column will fall down and the ignition switch is relatively easy to get to. This is probably the only sensible way to get the switch replaced, because a fixed part of the heater ducting is less than an inch in front of one of the screws holding the switch in place.
Dropped steering column with the ignition lock to the right.
The ignition lock, with the igntion swith taken out (from the top).

 

Phew... I finally found the gremlin.
The car was originally sold to Germany and the second owner imported it to Sweden. (This is quite common in Europe since the EU Common Market got into full swing.) Now, while poking around looking for any "loose contacts", which really was the symptom all along, I peeked up to the very far left under the instrument panel and saw "the German Intruder". A Bosch box no: 8787035157.



I found about 2 !!! valid hits when searching for this item on Google. "It may be an Immobilzer or it may be a 250km/h speed limiter...". (The Google hits refered to German Toyota Supra cars from -94, which fits the bill of speed limiting...) I emailed Bosch, really hoping for nothing, but got a reply saying that "this is probably an immobilizer" and they told me that they didn't really have much info on it at all. (But I got some schematics for it so they were nice.)

Anyhow, when tapping this box, the car came alive, so I guessed that something was wrong either with the connector or inside the box. After unmounting it (1 screw), it had a rattling sound to it. Hmm, this may really be the problem.
The plastic box was simply clicked together, so a little persuation got it open without breaking it. I will now let a couple of pictures speak for themselves...

Loose contact ?? Luckily, these mechanical relays are available and I've already bought a couple from Germany. (They are Siemens parts number V23133-F1001-C133 and were used in various German cars in the mid-90's.)

I'll report back in a few days, when the part(s) arrive from Germany and I have them installed. Until then, thank you all, especially Yamae, for your support. This one was a bit special.

 

Hi edtbjon - I'm troubleshooting an issue similar to yours.

Can you tell me the location of this Bosch box? I see "far left under the instrument panel." I assume this is under the drivers side, up against the left wall under the dash? Do I need to remove any panels to find it?

I have a new ignition switch on order and haven't gotten up under there to look for this stuff yet, but would like some pointers before going in.

 

Also, it appears as though your box suffered water damage. Did you ever find the source where the water entered the box?

The reason I ask is, about 12 years ago my GS400 took extensive damage to the main junction box (If I recall correctly - I didn't fix it myself, a shop found it.) The reason this occurred was because during a windshield replacement some years earlier, the technician scraped the paint off the water channel below the windshield. This caused the channel to rust out over time, allowing water to drip down onto the junction box.

I wonder if this Bosch box could have suffered water damage from the same source problem - and also wanted to pass that info along to you in case you may have the same water issue.

 

That box is not used for USDM Lexus cars. It was only for some models for European market but as far as I knew, Toyota was not installing that type of aftermarket security system at the factory. The Bosch box must be installed locally in Europe.