I am working on a 1998 gs300 for my cousin.... it is giving a strange issue with the hvac blower motor. For some reason the blower motor which is brand new will only work with the key in "ACC" but will immediately shut off once you turn the key further to "on" or with the car running. In ACC It will function normally throught out all of the speeds but will not even try to work with the key in any other position. Along with that it is seriously draining the brand new battery down to nothing and i do mean 0.00 on a multimeter. You can leave a multimeter idle on the battery and just watch the voltage drop atleast 1.0 volt in less than a minute. I'm not a lexus owner or mechanic but i do know basics lol and i'm attempting to help my cousin who is a single mother of 4 kids who's budget wont allow her a real mechanic. It has a amperage draw of almost 12.5 amps directly off of the battery. I cant seem to find any of the fuse or relay layouts for this car and the fuse covers and owners manual are both MIA. Any of you GS owners ever experienced this problem and what did you do to find and fix it? I've done what i know considering i have no resources for this particular car.

by the way, the blower motor was just installed by someone else.... it appears to be a simple plug & play installation. Could i be missing something, could or would they have had to mess with any other wiring or anything that im overlooking. Could the problem be in the blower motor? relay? fuse? ground? I JUST DONT KNOW WHERE TO START!!!

I'm tempted to try to straight wire the blower, but there is still a issue with the battery draining. I'm taking a risk and assuming the 2 issues are related tho!!

 

There is a blower motor relay on the passenger side fuse box. It's actually above the fuse box you will have to fold back the carpet to get to it.
https://www.clublexus.com/forums/gs-second-generation/615231-stupid-question-where-is-the-blower-motor-fuse-relay-for-99-gs4.html

The other item is called the Blower Motor Resistor. Behind the passenger side dash CD changer. You will have to remove it to get to it.
https://www.clublexus.com/forums/gs-second-generation/641328-98-gs-300-ac-fan-stuck-in-high-position.html

 

I would go on and pull fuses until the amp draw stops. however, since that blower motor seems to be the last thing that has been done, before the problems seemed to start, begin with that.