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1999 lexus gs400 no ac or heat blowing

Hi all, i have a 99 lexus gs400, the inside lights/radio were not working, so i replaced the fuses, yay. Now the ac/heat no longer blow through the vents. It worked fine prior to changing the fuses out. Please help me, what do i do? It does make a click noise when changing the modes, but no air or heat blowing at all, i can hear the car idle differently when turning off/on but nothing else.

Any help would be appreciated!

Turn the ignition on.

Set the blower speed to high.

Reach under the passenger side of the dash, and with a handle of a screwdriver rap on the blower motor.

If the blower starts working, replace the blower motor.


I tried that, it did not work, I also tapped on the resistor no dice either.

It literally was blowing great before i updated the fuses listed above.

Try to get 12V directly to the blower motor (bypassing the switch and the resistor) and see if the motor runs. If so, the switch or resistor are suspect. If not, a new or good used motor is called for.

I know this sounds stupid, but what exactly does that mean? I’m not real car smart.

Doesn’t sound stupid, but either bring it to a mechanic, he can test it, or if you know someone who works on cars they may be able to help.

Check fuse # 9; heater, it is in the same row as the radio fuse # 12.

Fuse # 9 powers the relay that supplies power to the blower module.

yep- recheck the fuses. Make sure it is in correctly, make sure you didn’t blow it, and then proceed.

From your description, it sounds like the a/c switches are working fine (as the change in engine sounds likely means the a/c compressor is engaging,) so this is just a blower issue.

Would fuse 9 be on passenger or driver side? I have fuses on both sides plus under hood.

If its not the fuses does this mean blower motor or resistor? I’m just having a hard time thinking one of those happened simply after changing fuses lol but then again I’m the worst person to try to work in cars.

Fuse #9 is in the drivers side fuse block. In which fuse block did you replace fuses?

I checked and replaced it just now, didnt work. I only replaced fuses on passenger side and under hood. 5-30 amp fuses only

Any other suggestions?

Looks like this is your next step.

Unfortunately. Thanks for trying to help everyone.

Hi everyone. The dealership literally gave up and couldnt figure out the issue. Blower motor is good, resistor is good, servo is good, compressor kicking on, heater fuse and blower motor relay good. I have no idea what to do at this point, im very frustrated. All of this just because i changed fuses so my inside lights would work