NEW MEMBER TO THIS FORUM, BUT VERY FAMILIAR WITH IT. I USE THIS SITE FOR ANY RESEARCH I DO ON MY 1ST GEN LS400..

ANYWAYS, TO BEGIN WITH WHAT I BELIEVE MIGHT BE MY IGNITION SWITCH, I WILL GIVE SOME BACKGROUND INFO FIRST.

MY LS HAD OVERHEATING PROBLEMS DUE TO MY HEATER CORE GOING OUT SO I BYPASSED IT AND REFILLED THE COOLANT. SHE'S NO LONGER RUNNING HOT. NOW WHILE THIS WAS HAPPENING, EVERY TIME MY MOTOR GOT TOO HOT AFTER I SHUT IT OFF, IT WOULD NOT TURN BACK ON. IT DID THIS ABOUT DIFFERENT 3 TIMES. AND IT WOULD TAKE A FEW HOURS UNTIL MY CAR WOULD TURN BACK ON.. I THOUGHT THIS WAS A SAFETY FEATURE FROM THE COMPUTER BECAUSE IT WOULDN'T START THE CAR UNTIL IT WAS COOL AGAIN IN ORDER TO PREVENT DAMAGING THE MOTOR.
NOW.. LET ME DESCRIBE EXACTLY WHAT HAPPENS WHEN I SAY IT WOULDN'T START... THERE ARE THE 3 POSITIONS ON THE IGNITION CYLINDER (ACC. ON. AND CRANKING ON THE MOTOR) SO WHAT HAPPENED WAS WHEN I TURNED THE KEY OR CYLINDER FROM OFF TO ON, EVERYTHING POWERS ON FULLY ILLUMINATED MEANING THAT THE BATTERY HAS JUICE. I EVEN GOT A JUMP TO BE SURE. ANYWAY, THEN WHEN I ATTEMPT TO TURN IT OVER, EVERYTHING POWERS OFF AND I CAN HEAR SOME RELAY CLICK AS IF ITS TRYING TO ENGAGE. IT SOUNDS TO ME AS IF THERE IS NO SIGNAL GETTING TO THE STARTER.

LIKE I SAID.. I THOUGHT THIS WAS A SAFETY FEATURE BECAUSE IT WAS RUNNING HOT AND WAS INTERMITTENT. BUT, NOW THAT I FIXED MY OVERHEATING PROBLEM IT DID IT AGAIN WHEN I WAS LEAVING WORK (ENGINE COLD AS POSSIBLE) AND IT DID IT AGAIN, SECOND TRY..VROOM.. STARTED RIGHT UP. I WAS LIKE UHH..WHAT THE HECK?
SO, I DROVE UP TO MY HOUSE (ABOUT 10 MILES UP) WENT INSIDE, THEN ABOUT 4 HOURS LATER I CAME BACK OUT TO RUN TO THE SUPER MARKET VERY QUICK, AND DEAD! SAME THING EXCEPT THIS TIME, NO SECOND CHANCE.. IT WOULD NOT START UP FOR ANYTHING. I EVEN TRIED RUNNING A DIAGNOTIC CODE CHECK AND IT CAME UP EMPTY..NO CODES!
THIS IS WHY NOW SUSPECT IT IS AN IGNITION SWITCH. NO I HAVE NOT CHECKED THE FUSES WHICH I WILL DO TODAY AFTER WORK, HOWEVER I DON'T SUSPECT ITS A FUSE BECAUSE IT WAS AN INTERMITTENT PROBLEM AND IS NOW COMPLETELY FAULTY. AND I HAVE NO CLUE HOW TO REPLACE THE SWITCH EITHER, SO BEFORE I GET TO IT, I'D LIKE SOME INSIGHT ON WHAT YOU MIGHT SUSPECT MY PROBLEM IS. PLEASE LET ME KNOW WHAT YOU THINK. THANK YOU IN ADVANCE

 

read up all you can on replacing the starter... we have done it twice on ours..not really "hard", but it takes some time to get it done... your ign switch is probably ok...
ps, dont use caps.. we all read very well.

 

What exactly makes you think its the starter though? I need detail please I just want to be as close to 100% sure on the culprit of my issue before I go off replacing things.

 

The symptoms your describing sound like bad contacts on the starter. When they start to wear out the problem is usually intermittent. The starter is mounted under the intake manifold. It is susepible to heat.

 

Check for power at the start terminal of the ignition switch. If you have it and the starter doesn't work, its either the starter solenoid or even the security system can cause starter problems, you will need a diagram for that stuff. You say 1st gen there are 2 versions of that. 90 to 92 or 93 to 94 what do you have?

 

I have a 1990. Sorry I forgot to mention that at first, that's probably just as important as the problem itself

Can you be a bit more descriptive as far as which terminal on the switch would be the start terminal.. pictures ect..?
Also, what exactly what do you mean by the security system causing problems?

by the way thanks for your input I appreciate your time..

 

forget about security, dicer was just covering all the "could be's" and it is extremely RARE for the ign switch to go bad in stages, (working/not working) but starter solenoid contacts COMMON..
WE (my nephew mechanic) have never replaced the complete starter, just the solenoid contacts.. (see below) but most folks (who dont have a built in mechanic) replace the starter..(just in case)
good luck..

 

Use your smart brain. There is an easy method to distinguish.
I'd simply check the current applying a clamp meter to the battery negative cable. If it's not available, a simple ampere meter is still OK to use but be careful when you hook up since there goes a big inrush current.

When the ignition switch is failed, the current increase is just a little bit because it can't drive the starter relay nor the solenoid.
When the starter's contact is failed, the current increase is a few amps or a bit more because the solenoid in the starter eats only that much of current.