I am having all of these issues mentioned on my 99 gs 300. After having issues starting (all of the ones mentioned on this thread) I thought I needed a new started so I purchased a brand new OEM (not lexus or toyota brand) for $110. As I was pulling it into the garage I shut it off and the starter continued to crank over. I ultimately hadn't read this thread and took the battery terminals off.

I also had a windsheild replace and am going to check the box to see if there is any water sitting in there and to also re-seat the starter, and main relays. Will keep all posted.

jledue - if it turns out that your main block has water in it, make sure to get the windshield checked out asap.

Because this electrical problem was intermittent and went on for some time, I didn't know about the rust caused by the leakage until I had surface rust at the top of the windshield. This all required that the windshield be removed, the rust repaired, and my whole roof repainted at a cost of $900.

I have a 99 GS300. About the past few weeks, i have hade problems starting the car. After ther car sits more than a few hours, it would try to turn over a few times before actually doing so. Then it would start up everytime for the rest of the day. Well this morning she did the same, but i noticed a weird sound coming from the engine. I turne the ignition off and the car tried to start itself! It wouldnt stop. So i turned the key back to the "on" position, and the car ran, but with the same noise. I lifted the hood, saw white smoke coming from the area beneath the manidold. Also smelled electrical. as the smoke started to disappear, the noise went away. I then tried turning off the ignition again and was successful....only problem now is it wont do anything when i turn the ignition! One "click", then nothing. All lights work and seem to be normal.
With that being said, what in the world was the white smoke?

99GS Boi -

I'd be willing to bet that even while your car was running, your starter was still engaged. Mine wouldn't quit until I pulled the starter relay.

Not sure about the white smoke, tho...

Couldnt really tell if it was or not due to the tears in my eyes! Just got the car 2 months ago...rims, LED tails, and a kenwood DVD already installed...Halos on the way, now this happens.

Had one of my workers call the local Lex dealer (I'm in Holland on a military assignment) since I dont speak a lick of Dutch. Just over the phone from what was translated to them, they think its a short somewhere between the ignition and the starter...but i'm sure it burned out the starter motor or at least destroyed some contacts. Wasnt a lot of smoke but it was noticeable. Gonna have it towed to them maybe in the morning. One positive thing, the dutch are very honest, the dealers wont try to stiff you with a bunch of unnecessary parts.

I am experiencing my of the same issues as GS400Dave. A couple of days ago, we experienced some heavy rains here. After this when I started my car, the starter kept engaging. I had to disconnect the negative terminal on the battery to get it to stop. A couple of hours later I reconnected and the car was running like a champ. After leaving it sitting for the evening, I heard the starter motor going again. I ran out to see the starter motor engaging with no key in the ignition.

I am confused as to how I should proceed. I brought the car last year used and am uncertain about whether the windshield has been replaced. I am also having a hard time understanding how a windshield leak would lead to water getting into the fuse box.

my battery is brand new and the terminals are clean.

My mechanic suggested changing the starter relay, but it appears as though most all people are experiencing problems with the main relay. Has anyone had success in quelling these symptoms by changing the main relay?

TK - it wasn't the fuse box down by your kick plate. It was the main junction box, and since I didn't do the replace I'm not even sure where it was. But they gave me the old part, it's about a 4x5" plastic box, and it was definitely corroding from the metal contacts.

It seems to me that the relay is the more likely problem, but it wasn't for me.

Thank you gs400dave. I am having the exact same problem as you. Are you 100% sure the main junction box that your mechanic replaced is not the one down by the drivers kick plate? That box contains the starter fuse and it would make sense that this box would get wet if the windshield was leaking and letting water in behind the dashboard. The only box under the hood that could possibly cause this to happen would be the long one in front of the battery - the one that contains the Main and Starter Relays. But that one is far from the windshield.

The 4x5" plastic box that you described - what colour was it? did it have a lid as well? Was it perfectly rectangular?

Has anybody identified the "main junction box". I am having the exact same problems!

my 98 lexus ls400 would not start no click no sounds turns out that while beating the hell out of my glovebox or atleast beneath the thing where the fan is located it loosened a wiring harness and caused the intermittent starts eventually beating it to hard where the car just shut off an would not cut back on until I took the glovevoox out an realized that it was the culprit to it shutting off an then second realizing that it caused the start problem cause I never had a problem since! Of course while doing this I used a paper clip to bypass the relay fuse an get the car crunk to drive inevitably ****ing my car up cause now the starter won’t engage it just makes a whining noise but I hope this relates to yours some how maybe it’ll relate to someone else’s! Good luck