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No ac or heat blowing through vents

 
Old 03-15-19, 08:42 AM
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lexus99gs4
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Default No ac or heat blowing through vents

Hi, please help me. I bought a 99 lexus gs400 3 weeks ago. My inside lights/radio wasnt working so i replaced the fuses, yay they now work. However, now the ac/heat doesn't blow at all. The LCD lights up, you can switch modes and hear servo change, the compressor kicks on, it is cold/hot barely felt at higher speeds but not blowing. I've replaced the blower motor, still not working. I checked the resistor and it is good, the 10A fuse and 50A fuse under hood is good as well (changed them out to be safe). What do I do now?

I have no idea what else to test or check.I'm very frustrated, I can't defrost, use ac or heat at this time.
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Old 03-15-19, 02:00 PM
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Is the blower getting 12v and ground? Is the fuse getting 12v? Use a test light or multimeter to test.
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Old 03-15-19, 03:54 PM
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Originally Posted by Debonair View Post
Is the blower getting 12v and ground? Is the fuse getting 12v? Use a test light or multimeter to test.
+1.

Did you replace the blower motor with new, or another older unit.

Check the blower motor is getting power... if you put in another older unit, that one also might be bad.

Always check voltages.
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Old 03-18-19, 06:13 AM
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Originally Posted by sbagdon View Post
+1.

Did you replace the blower motor with new, or another older unit.

Check the blower motor is getting power... if you put in another older unit, that one also might be bad.

Always check voltages.
I put in a brand new blower motor, did not work. I also replaced the relay, I checked the resistor with multi meter, good as well. This guy online said he had the same problem and replaced ignition switch? That doesn't make sense at all lol.

I do not know how to the the fuse to make sure it is getting 12V, i know the fuses and relay are good cause i tested them, but can you explain how to test for 12V?
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Old 03-18-19, 11:35 AM
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Originally Posted by lexus99gs4 View Post
I put in a brand new blower motor, did not work. I also replaced the relay, I checked the resistor with multi meter, good as well. This guy online said he had the same problem and replaced ignition switch? That doesn't make sense at all lol.

I do not know how to the the fuse to make sure it is getting 12V, i know the fuses and relay are good cause i tested them, but can you explain how to test for 12V?
www.youtube.com/watch?v=ksrsXwwukFc
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Old 03-19-19, 08:46 AM
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Thanks for the video. I checked the fuses and they are good. This is really odd.
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Old 03-19-19, 08:35 PM
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Maybe the HVAC controller. Do you have factory navigation or radio with the seperate HVAC controller?

Could be the wiring going to the blower too. You basically need to start testing everything between the controller and the blower.
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Old Yesterday, 05:59 AM
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Well you can feel cold ac or hot heat depending on which it is on at higher speeds, but just barely. I had a custom radio, just bought the car a few weeks ago, but the guy had wiring going from the trunk to to the radio. The radio does not work and is not hooked up, but when i put new fuses in the 6 cd changer under the glove box starting changing disc and the inside lights started working. How would i test the wiring going to the blower?

What would happen if i accidentally put the wrong size fuse in a slot and figured it out later/changed to the correct one? Could that have caused something to blow or short? When replacing passenger side fuses, the driver side fuse box cover was over there so i thought that was the fuses to put in. I had to research online to find the passenger side fuse panel diagram and replace with the correct ones.
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