AC/Heat blower fan intermittent
#1
Driver School Candidate
Thread Starter
AC/Heat blower fan intermittent
Searched threads, no one seems to have my problem. 2001 RX300; 135K
AC blower gives indication of fan speed when **** is turned, but no air comes out the vents. Does not matter in auto or manual mode. AC on off switch works, and compressor engages when fan **** turned (only way to turn AC on manually) and disengages when AC button is pushed. This has happened about 5 times in last 3 months.
First time: turned car off and sit for a couple minutes in the Georgia heat then started car and fan/ac worked.
2nd time: Restarting didn't work,cycled AC on/off didn't work, gave it a light tap on the dash beside the LCD display. Worked :: (thinking loose connection)
next time: all the usual, restarting, cycling and light tap didn't work. I was on a trip and it was pretty hot, opened hood to verify again the compressor was engaging. Spouse was cycling system on off. She was not touching anything and I shut the hood and it came on. Didn't turn engine or AC off til I got home.
I don't think it is freon cause it is cold air when fan decides to engage.
Does not matter what mode I am in, Auto/manual/ or direction of air, floor/defrost/face etc.
Any help appreciated,
I will look at fuses and such this weekend, but a fuse usually is blown or not so system should be off or on, not intermittent.
AC blower gives indication of fan speed when **** is turned, but no air comes out the vents. Does not matter in auto or manual mode. AC on off switch works, and compressor engages when fan **** turned (only way to turn AC on manually) and disengages when AC button is pushed. This has happened about 5 times in last 3 months.
First time: turned car off and sit for a couple minutes in the Georgia heat then started car and fan/ac worked.
2nd time: Restarting didn't work,cycled AC on/off didn't work, gave it a light tap on the dash beside the LCD display. Worked :: (thinking loose connection)
next time: all the usual, restarting, cycling and light tap didn't work. I was on a trip and it was pretty hot, opened hood to verify again the compressor was engaging. Spouse was cycling system on off. She was not touching anything and I shut the hood and it came on. Didn't turn engine or AC off til I got home.
I don't think it is freon cause it is cold air when fan decides to engage.
Does not matter what mode I am in, Auto/manual/ or direction of air, floor/defrost/face etc.
Any help appreciated,
I will look at fuses and such this weekend, but a fuse usually is blown or not so system should be off or on, not intermittent.
Last edited by 2ks; 09-26-12 at 09:40 AM.
#2
Driver School Candidate
Thread Starter
Anybody? Drove it yesterday and the fan didn't come on twice while doing errands. Found if i give it a tap below the glove box seems to rattle something and it comes on. This worked 2 times, but I will look under there later today. I don't like having to smack things on the dash. Always afraid the airbag is gonna deploy, big $$$. But in the 90 degree Georgia heat it the a/c fan has to work. Too old and wimpy to drive without it.
#3
Moderator
Intermittent problems are hard to narrow down.
I can only give you some general information ...
The blower has a control module (located near the servos). Please search as I have pointed it out in another thread.
The ecu sends different voltage to the control module and display. You can see the lcd indicate faster or slower speed. The control module then steps down the the +12v to lower voltage and sends it to the blower.
Mine had a hard fail of the control module and it was an easy diagnosis. If you have access to wiring diagram, you can bridge the module and test if blower always works for you at max speed.
Your blower motor can be bad and some times the motors fail to get going as well. There can be a bad connection too.
Happy hunting.
Salim
I can only give you some general information ...
The blower has a control module (located near the servos). Please search as I have pointed it out in another thread.
The ecu sends different voltage to the control module and display. You can see the lcd indicate faster or slower speed. The control module then steps down the the +12v to lower voltage and sends it to the blower.
Mine had a hard fail of the control module and it was an easy diagnosis. If you have access to wiring diagram, you can bridge the module and test if blower always works for you at max speed.
Your blower motor can be bad and some times the motors fail to get going as well. There can be a bad connection too.
Happy hunting.
Salim
#4
Driver School Candidate
Thread Starter
Thanks Salim,
I just narrowed it down, did a shake/wiggle of all wires/connectors i could find around the blower to include the control module. I couldn't get it to fail at first and when the blower was on and working i wiggled everything and it never failed. Ruled out loose connections. However as soon as i was about to give up for today and backed it out of the garage the blower failed to come on. I took a long narrow screwdriver and moved some of the wires just behind the glove box i couldn't reach with no fix. lightly tapped the control module with the handle of the screwdriver and whalahh!! on it came. cycled the system/ and engine off/on till it failed again and repeated, tapped the control module and the blower came on again. Will start searching for a control module tonight. My eyes are too old to see the numbers on the module installed, so i will have to wait till i remove it to verify part number. OEM module I could see Toyota and partial p/n. It is still intermittent for now but I am sure it is on its way to the parts graveyard. Thanks for the help.
I just narrowed it down, did a shake/wiggle of all wires/connectors i could find around the blower to include the control module. I couldn't get it to fail at first and when the blower was on and working i wiggled everything and it never failed. Ruled out loose connections. However as soon as i was about to give up for today and backed it out of the garage the blower failed to come on. I took a long narrow screwdriver and moved some of the wires just behind the glove box i couldn't reach with no fix. lightly tapped the control module with the handle of the screwdriver and whalahh!! on it came. cycled the system/ and engine off/on till it failed again and repeated, tapped the control module and the blower came on again. Will start searching for a control module tonight. My eyes are too old to see the numbers on the module installed, so i will have to wait till i remove it to verify part number. OEM module I could see Toyota and partial p/n. It is still intermittent for now but I am sure it is on its way to the parts graveyard. Thanks for the help.
#5
Moderator
I bought mine from Sewell. The part number has been changed but the new one works fine. It is bit expensive and some one was selling it as a used part for almost 50% off the new one. The 50% off was in a bad shape (exposed to weather ). Incidentally the part is not hermetically sealed. I decided to get the new part and have no regrets.
The module is held by one screw, but the other end hooks over.
Salim
The module is held by one screw, but the other end hooks over.
Salim
#6
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Join Date: Mar 2012
Location: WI
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could this be why when I put a new servo into my 99 lexus for air mix that it worked at first perfect then stopped and did nothing once shut off? I disconnected battery a few times and had it work when I adjusted the temp but now I cant get it to move. Brand new servo from sewell,,,,,,Help Salim
#7
Driver School Candidate
Anybody? Drove it yesterday and the fan didn't come on twice while doing errands. Found if i give it a tap below the glove box seems to rattle something and it comes on. This worked 2 times, but I will look under there later today. I don't like having to smack things on the dash. Always afraid the airbag is gonna deploy, big $$$. But in the 90 degree Georgia heat it the a/c fan has to work. Too old and wimpy to drive without it.
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