SC- 1st Gen (1992-2000)

1995 SC300 Fan Speed/Blower Issues

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Old 08-22-16, 07:30 PM
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acturbo
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Default 1995 SC300 Fan Speed/Blower Issues

Hey guys, new here on the forum. I tried searching for the answer to my question but could not find the answer. Anyways.........

Just got my first 1995 Lexus SC300. I am having an issue with the blower motor only works on high. I have found a few threads relating to the issue but I have a few specific questions about getting this fixed.

So here's the story:

Fan speed only works on high, read a few threads stating that I may need either a blower motor resistor or a blower motor transistor. A friend of mine has a '93 SC300 so I figured I try to swap the resistor over and see if it fixed the problem. Problem being it looks like the setup is either different between the model years or someone has messed with the wiring harness to make it work. I am heavily leaning toward there being differences between the model years seeing as how there is no hole behind the glove box for the resistor on the '95 to sit. There are red and white wires present above and below the dash for the resistor on the '93 and none on the '95. When searching google for the resistor most of the parts come up as 92-2000 which doesn't make sense if they are different. I put pictures of both the '93 and the '95 below. If they are indeed different can someone point me in the right direction as to where to look or what parts I may need to replace? Thanks in advance for any help.

Pictures of '93

'93 behind glove box

'93 under glove box

'93 under glove boxPictures of '95:
'95 behind glove box

'95 under glove box

'95 under dash

Resistor in question out of the '93:
Resistor out of '93



Old 08-22-16, 07:55 PM
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RXRodger
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For the 93 this is the circuit. If it is like this, then probably is the transistor. But, like you say, they must be slightly different.
Old 08-22-16, 08:07 PM
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acturbo
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[QUOTE=RXRodger;9593869]For the 93 this is the circuit. If it is like this, then probably is the transistor. But, like you say, they must be slightly different.

Thanks Rodger,

If someone only had a diagram for the '95 to compare to.................... I just think its strange when I search for the part for the '95 the picture of the part I have comes up. You would think if it was a different part or didn't exist one would not be able to find it or it would show the correct part. Stumped so far
Old 08-24-16, 11:42 AM
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The 95 and above didn't have the blower resistor that slows down the fan speed on the 92-94 . Fan Speed was controlled by the HVAC control assembly .
Old 08-24-16, 05:09 PM
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acturbo
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Originally Posted by gerrb
The 95 and above didn't have the blower resistor that slows down the fan speed on the 92-94 . Fan Speed was controlled by the HVAC control assembly .
Crap, so I need a whole new HVAC control head? Ugh. Figures. Thanks for the reply.
Old 08-24-16, 05:22 PM
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I went through the AC wiring diagrams of every year 1992 - 2000 today . Only the 1992-1994 has the Blower Resistor to control Fan Speed. The rest is controlled by the HVAC Control Assembly. When I have time I will post a 1994 and 1995 AC wiring diagram so you can see the differences.
Old 08-24-16, 05:42 PM
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Originally Posted by gerrb
I went through the AC wiring diagrams of every year 1992 - 2000 today . Only the 1992-1994 has the Blower Resistor to control Fan Speed. The rest is controlled by the HVAC Control Assembly. When I have time I will post a 1994 and 1995 AC wiring diagram so you can see the differences.
Thanks appreciate it. You don't by chance know if all 95 and up control heads will work on a 95 do you?
Old 08-25-16, 05:33 AM
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Originally Posted by acturbo
Thanks appreciate it. You don't by chance know if all 95 and up control heads will work on a 95 do you?
Incidentally I tried a 97 control head from my 97 into a 95 that I used to have and it did work . I will look in detail the 97 diagrams if there are differences and no ill effects if its control head will be used on the 95

here are the 94 and 95 diagrams so you can compare :

94 AC wiring diagrams . You see the blower resistor I encircled which the 95 and above do not have

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95 AC wiring diagrams

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Old 08-25-16, 05:56 PM
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Originally Posted by gerrb
Incidentally I tried a 97 control head from my 97 into a 95 that I used to have and it did work . I will look in detail the 97 diagrams if there are differences and no ill effects if its control head will be used on the 95

here are the 94 and 95 diagrams so you can compare :

94 AC wiring diagrams . You see the blower resistor I encircled which the 95 and above do not have





95 AC wiring diagrams



Thanks Gerrb, I really appreciate all the help. Hard to find this info on the web. Looks like I'll have to keep my eye out for a used control head..........................
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