Ive been having some problems with my 92 sc400.

1) Brake lights work but tail lights wont

2) My dash lights wont turn off even though the keys are out of the ignition.

 

On the brake light issue try replacing the brake switch behind the pedal. It is only like around $25.00 bucks or so. Could be the problem and many Toyota/Lexus vehicles have this same sensor. I am wondering if this sensor is tied into this problem????

Not sure on the other.... Do you mean the lights on the cluster and climate control? How are you turning them off now? Disabling the battery?

 

Reset the ECU, just disconnect the negative battery terminal and leave it there for 5 minutes.

 

It seems the issues could be tied together if the headlight switch malfunctions.

I think the brake switch is fine, the brake lights would be stuck on or off. At least thats the issue I ever had with my Corolla.

 

Yes the gauge lights, I havent had time to play with it yet but this week I will. If it were the relays causing the problem how much am I looking at when it comes to repairs? Ok I will try resetting the ECU by leaving the negative battery post of for 5 Minutes Ill let you know if that works.