My defrost button blinks for 25 seconds when I start the car. After it stops blinking the fan comes on but I won't defrost the front windshield, air only comes out the side vents.
beavis17
2007 Camry LE - Auto, manual climate controls.
Sorry for the old post bump but was there a solution found to this issue? I have the exact same problem - rear defrost light blinks for about 30 seconds on startup and no HVAC controls function at all. After 30 seconds, controls will all function - rear defroster will work, blower will blow, temp changes from cold to hot. What DOESN"T work is the front defrost - no air gets routed up through the dashboard defrost vents when in either full defrost or defrost/floor mode. The air keeps coming through the dash vents the whole time.
From some reading here i have found I can check fuses under the hood...any specific ones for this issue? Also saw to check the actuator motor/controller on the drivers side above the throttle pedal...will check that tonight.
One other note - if the car is fully warmed up and is shut off and then restarted within a very short period of time ( say 5-10 minutes), the defrost does NOT blink....and all hvac controls are active immedately.
Sorry for the old post bump but was there a solution found to this issue? I have the exact same problem - rear defrost light blinks for about 30 seconds on startup and no HVAC controls function at all. After 30 seconds, controls will all function - rear defroster will work, blower will blow, temp changes from cold to hot. What DOESN"T work is the front defrost - no air gets routed up through the dashboard defrost vents when in either full defrost or defrost/floor mode. The air keeps coming through the dash vents the whole time.
From some reading here i have found I can check fuses under the hood...any specific ones for this issue? Also saw to check the actuator motor/controller on the drivers side above the throttle pedal...will check that tonight.
One other note - if the car is fully warmed up and is shut off and then restarted within a very short period of time ( say 5-10 minutes), the defrost does NOT blink....and all hvac controls are active immedately.
I had this diagnosed on my last oil change and they were able to get a code, the part they said needs replacing is the AC Amplifier Assembly. Part number is 88650-06310.
Upon some investigation, it seems that these can be had new or used pretty easily on the standard part supply shops/ebay/etc. From the looks of what I see it's part of the overall blower assembly located behind the glove box, but i'm unsure as to exactly how much of the dash needs to be disassembled to access it. The standard chilton's manuals don't go into enough detail for this component - is this something that would only be in a dealer manual? There are diagrams of the assembly itself but not clear if the entire thing needs to be removed first.
Anyone ever replace one of these? Part #9 is the part in question on the attached photo
Upon some investigation, it seems that these can be had new or used pretty easily on the standard part supply shops/ebay/etc. From the looks of what I see it's part of the overall blower assembly located behind the glove box, but i'm unsure as to exactly how much of the dash needs to be disassembled to access it. The standard chilton's manuals don't go into enough detail for this component - is this something that would only be in a dealer manual? There are diagrams of the assembly itself but not clear if the entire thing needs to be removed first.
Anyone ever replace one of these? Part #9 is the part in question on the attached photo
Attachments
Ok, here was my fix for the blinking defroster light. There was very little information anywhere on the web about this, and definitely no actual troubleshooting that I could find. Replacing the entire evaporator box didn't seem like the best answer for me, so here is my process:
Symptoms: Defroster light would blink for 20-30 seconds upon startup. During this period the entire A/C system would not function. When the blinking stopped, the A/C system would operate, HOWEVER... the mode selector switch would not change the mode of operation (defroster, vents, floor vents, etc). The fan speed selector switch worked fine, the temperature selector switch worked fine.
Research: Pulled out the wiring diagram, parts diagram, etc and started trying to figure it out. The temperature selector switch and the mode selector switch both operate servo motors on the passenger side of the evaporator box. They are not that easy to get to, but I pulled the glove box and investigated. With the system running, I had my son turn the temperature switch, I could see and hear the servo motor operating and moving levers. This was all ok. It is the bottom servo motor. I then had him turn the mode selector switch... although you can hear some change, the big round disk the servo motor drives was not moving at all. This is the upper servo motor. I went back to the wiring diagram and determined it could only be two things: A bad AC Amplifier Assembly -or- a bad servo motor.
1st Fix attempt: I got my OBDII scan tool and checked for codes. Nothing. According to research, the blinking light is your only indicator that there is something wrong in the A/C electrical system. If anyone actually saw with their own eyes a code, please let us know. Since there is no way to check the AC Amplifier, I had to get a new part. Off to Ebay and $20 later, I had an AC Amplifier. I plugged it in, no change. I had to take the leap of faith and assume this used AC Amplifier was ok. I moved on to the servos.
2nd Fix attempt: I started looking at the servos and how to get the entire 'plate' out of the car without removing the dash. You can do it. It is not easy, but with patience (and a carefully wielded pry bar) you can do it. The plate holds both the upper and lower servo. I got it disconnected from the vehicle and swapped the plugs on the servos. The non-functioning problem did not move. The top servo would still not respond to any selector switch, however the bottom servo kept working. This told me the top servo (mode selector servo) was bad. I disassembled it and tried to get it working... no dice. The motor itself inside the servo would not respond to even direct voltage from a battery. Off to Ebay I go.... for $30, I got a new servo (doesn't matter which one, I just needed the little internal motor). I ended up finding an exact replacement however, with the big white mode selector disk still on it. This should be a direct plug and play.
Verifying fix: I took the new servo motor and the existing working servo motor to the car (they are disconnected from the plate at this time) just to see if they worked. I plugged them both in, turned the car on, and the blinking light did NOT show up. Possible success? I moved the Temp Selector switch, that servo still worked. I turned the Mode Selector switch, the new servo DID NOT MOVE.... suck! I turned the car off to think for a minute. When I did, I heard the servo move. It was resetting! I turned the car back on and tested both servos, they worked! I tried this several times. I found out that the first time the servo is energized, if it's physical position does not agree with the mode selector switch setting, it will not move, but it resets its position at Key Off.
Now the tricky part: Remember when we pulled the plate out with both servos? Well it took a bit of force, and wasn't going to just slip back in place. The real tricky bit was that is has to slip in place and precisely capture the pins of three different dampers. This was going to be a challenge. I spent at least 3 hours doing the next bit. I turned the A/C system on, and manually moved each lever to determine exactly what each one did. I then stared dumbly at the big white wheel with all it's slots on it and thought "oh boy". I took the servo off the plate so I could hold it in my hand. I put the big white wheel on it and held it in place by hand, trying to align all the bits at the same time. Nightmare. I finally figured out it was easier to do with the A/C running, as the air flow would hold the dampers in position. By trial and error, I was able to determine where each pin went and then get the servo to move through all of its positions (while I held it in place) without binding or other issues. I then installed the servos back in the plate and started mounting them back in. Took a bit of fiddling, and the aforementioned pry bar, but I got it in and got it working.
All in all it was a pain, but much less so than removing the dash. For $50 and the better part of two days over a weekend, I got the problem solved and the A/C is functioning properly now for at least 4 weeks.
I have pictures, I may try to edit this thread later and add pics if it would help anyone.
Symptoms: Defroster light would blink for 20-30 seconds upon startup. During this period the entire A/C system would not function. When the blinking stopped, the A/C system would operate, HOWEVER... the mode selector switch would not change the mode of operation (defroster, vents, floor vents, etc). The fan speed selector switch worked fine, the temperature selector switch worked fine.
Research: Pulled out the wiring diagram, parts diagram, etc and started trying to figure it out. The temperature selector switch and the mode selector switch both operate servo motors on the passenger side of the evaporator box. They are not that easy to get to, but I pulled the glove box and investigated. With the system running, I had my son turn the temperature switch, I could see and hear the servo motor operating and moving levers. This was all ok. It is the bottom servo motor. I then had him turn the mode selector switch... although you can hear some change, the big round disk the servo motor drives was not moving at all. This is the upper servo motor. I went back to the wiring diagram and determined it could only be two things: A bad AC Amplifier Assembly -or- a bad servo motor.
1st Fix attempt: I got my OBDII scan tool and checked for codes. Nothing. According to research, the blinking light is your only indicator that there is something wrong in the A/C electrical system. If anyone actually saw with their own eyes a code, please let us know. Since there is no way to check the AC Amplifier, I had to get a new part. Off to Ebay and $20 later, I had an AC Amplifier. I plugged it in, no change. I had to take the leap of faith and assume this used AC Amplifier was ok. I moved on to the servos.
2nd Fix attempt: I started looking at the servos and how to get the entire 'plate' out of the car without removing the dash. You can do it. It is not easy, but with patience (and a carefully wielded pry bar) you can do it. The plate holds both the upper and lower servo. I got it disconnected from the vehicle and swapped the plugs on the servos. The non-functioning problem did not move. The top servo would still not respond to any selector switch, however the bottom servo kept working. This told me the top servo (mode selector servo) was bad. I disassembled it and tried to get it working... no dice. The motor itself inside the servo would not respond to even direct voltage from a battery. Off to Ebay I go.... for $30, I got a new servo (doesn't matter which one, I just needed the little internal motor). I ended up finding an exact replacement however, with the big white mode selector disk still on it. This should be a direct plug and play.
Verifying fix: I took the new servo motor and the existing working servo motor to the car (they are disconnected from the plate at this time) just to see if they worked. I plugged them both in, turned the car on, and the blinking light did NOT show up. Possible success? I moved the Temp Selector switch, that servo still worked. I turned the Mode Selector switch, the new servo DID NOT MOVE.... suck! I turned the car off to think for a minute. When I did, I heard the servo move. It was resetting! I turned the car back on and tested both servos, they worked! I tried this several times. I found out that the first time the servo is energized, if it's physical position does not agree with the mode selector switch setting, it will not move, but it resets its position at Key Off.
Now the tricky part: Remember when we pulled the plate out with both servos? Well it took a bit of force, and wasn't going to just slip back in place. The real tricky bit was that is has to slip in place and precisely capture the pins of three different dampers. This was going to be a challenge. I spent at least 3 hours doing the next bit. I turned the A/C system on, and manually moved each lever to determine exactly what each one did. I then stared dumbly at the big white wheel with all it's slots on it and thought "oh boy". I took the servo off the plate so I could hold it in my hand. I put the big white wheel on it and held it in place by hand, trying to align all the bits at the same time. Nightmare. I finally figured out it was easier to do with the A/C running, as the air flow would hold the dampers in position. By trial and error, I was able to determine where each pin went and then get the servo to move through all of its positions (while I held it in place) without binding or other issues. I then installed the servos back in the plate and started mounting them back in. Took a bit of fiddling, and the aforementioned pry bar, but I got it in and got it working.
All in all it was a pain, but much less so than removing the dash. For $50 and the better part of two days over a weekend, I got the problem solved and the A/C is functioning properly now for at least 4 weeks.
I have pictures, I may try to edit this thread later and add pics if it would help anyone.
@ekesz13
That was pretty heroic, thanks for the post.
I have 2010 Camry and recently the rear defrost light would blink on start up and none of the climate controls would work but after the light stopped blinking (about 30 secs) everything worked fine. I was worried that this was going to be a serious problem so I did a search and didn't find a lot of info regarding this error except that one or more of the climate control servos were dead or dying. I also learned that replacing the servos required removing the dashboard (not something I could do) so I was hoping to avoid an expensive repair and was even considering selling the car which has 120K miles.
I started to trouble shoot the problem and heard grinding noises coming from the passenger footwell when I operated the controls. I went to youtube and found some vids on how to remove my glove box and get access to the climate airbox. What i found was that all the white plastic gears were covered in carpet fibers and the motor was straining to operate the mechanism. So I removed a vent duct to get better access and then blew the carpet fibers off the gears with Dust Off canned air (as best I could) and then I sprayed everything I could reach with WD40 Silicone spray (its is compatible with plastic gears, do not use regular WD40 as that will probably damage the plastic gears).
Here is a pic of the motors that were having problems;
![Image]()
The motors are labeled (1) for the temp control, (2) for mode control and (3) for recirc. The noisiest motor was for mode control so I focused on that and its associated gears and mechanisms. Circled in yellow is the mount for a vent that blows hot or cold air into the passenger footwell. Here is a pic of the vent that I removed;
![Image]()
Since I didn't know how to remove that vent I broke it in two getting it out. It has multiple clips tagged with yellow lines but there were a number of other tabs on the back of the vent that I broke. Once I had it out I learned that there are two tabs to release it from the climate air box marked with red arrows. Fortunately, it was easy to fix with the zip tie however when I ripped it out (too aggressively) I broke a retaining tab on the airbox (in the first pic circled in red inside the yellow circle). In any case, I was able to get humpty dumpty back together though I had to install a screw and washer or replace the tab or the vent would rattle. The good news is that since blasting the plastic gears with silicone spray the defrost light has not blinked.
That was pretty heroic, thanks for the post.
I have 2010 Camry and recently the rear defrost light would blink on start up and none of the climate controls would work but after the light stopped blinking (about 30 secs) everything worked fine. I was worried that this was going to be a serious problem so I did a search and didn't find a lot of info regarding this error except that one or more of the climate control servos were dead or dying. I also learned that replacing the servos required removing the dashboard (not something I could do) so I was hoping to avoid an expensive repair and was even considering selling the car which has 120K miles.
I started to trouble shoot the problem and heard grinding noises coming from the passenger footwell when I operated the controls. I went to youtube and found some vids on how to remove my glove box and get access to the climate airbox. What i found was that all the white plastic gears were covered in carpet fibers and the motor was straining to operate the mechanism. So I removed a vent duct to get better access and then blew the carpet fibers off the gears with Dust Off canned air (as best I could) and then I sprayed everything I could reach with WD40 Silicone spray (its is compatible with plastic gears, do not use regular WD40 as that will probably damage the plastic gears).
Here is a pic of the motors that were having problems;
The motors are labeled (1) for the temp control, (2) for mode control and (3) for recirc. The noisiest motor was for mode control so I focused on that and its associated gears and mechanisms. Circled in yellow is the mount for a vent that blows hot or cold air into the passenger footwell. Here is a pic of the vent that I removed;
Since I didn't know how to remove that vent I broke it in two getting it out. It has multiple clips tagged with yellow lines but there were a number of other tabs on the back of the vent that I broke. Once I had it out I learned that there are two tabs to release it from the climate air box marked with red arrows. Fortunately, it was easy to fix with the zip tie however when I ripped it out (too aggressively) I broke a retaining tab on the airbox (in the first pic circled in red inside the yellow circle). In any case, I was able to get humpty dumpty back together though I had to install a screw and washer or replace the tab or the vent would rattle. The good news is that since blasting the plastic gears with silicone spray the defrost light has not blinked.
Attachments
Update
Bad news, the defrost light started blinking again but it only did it once in about two weeks since I lubed the gears with silicone spray so it was definitely an improvement. The lube probably reduces the force required to operate the gears so the servo motors don't have to strain so hard. In any case, I've probably bought my self some time before I have to deal with this and maybe I bought enough time so I can fix it in the Spring instead of losing heat or defrost during the Winter which would make it a critical repair.
Also, when I was working on the airbox I noted that when I turned off the key, after about 5 seconds, the servos perform some kind of position homing or maybe that is not normal, I don't know. Maybe the flashing defrost light is indicating a failure to home when I turn off the ignition. I'm going to keep an eye on it but hoping to avoid the expensive repair at the shop or the difficult repair that ekesz13 posted. I've read about a component called a AC amplifier (some kind of electronic doodad) and I am not sure what it does but I'm going to research what it does and replace it if it can be causing this problem.
Bad news, the defrost light started blinking again but it only did it once in about two weeks since I lubed the gears with silicone spray so it was definitely an improvement. The lube probably reduces the force required to operate the gears so the servo motors don't have to strain so hard. In any case, I've probably bought my self some time before I have to deal with this and maybe I bought enough time so I can fix it in the Spring instead of losing heat or defrost during the Winter which would make it a critical repair.
Also, when I was working on the airbox I noted that when I turned off the key, after about 5 seconds, the servos perform some kind of position homing or maybe that is not normal, I don't know. Maybe the flashing defrost light is indicating a failure to home when I turn off the ignition. I'm going to keep an eye on it but hoping to avoid the expensive repair at the shop or the difficult repair that ekesz13 posted. I've read about a component called a AC amplifier (some kind of electronic doodad) and I am not sure what it does but I'm going to research what it does and replace it if it can be causing this problem.
I don't know if is the amplifier or the servos that are causing the blinking light. It still does it but probably less than once per month so I am ignoring it till it gets worse, i.e. AC or Heater fail. I never found a definitive answer and I didn't spend much more time on this since I posted. I dread having to replace servos or the amplifier because either job looks difficult and would probably have to pay someon to do it which is expensive.
Thank you everyone for posting here, very helpful. I too had all these symptoms, blinking defrost button no control of heat or cold, recirculation or mode control. This summer the A/C was not working, so I did a thorough fuse check on the A/C system pulling the fuses and visibly checking them. I determined my A/C clutch was not engaging and didn't want to deal with it as it was early September and cooling down. The problem came in late October when it was cold and I needed the heat. First thing I did was check the fuses, but this time I just checked for continuity across the heads of the fuses using a meter and they all checked out. After performing all the troubleshooting in the above thread, about to pull the dash and get real serious I decided to check the fuses one more time. During my earlier troubleshooting I had inadvertently while upside down in low light put the fuse that powers the A/C amplifier in the one unused fuse slot, the slot between slot 8 and 9. I didn't read open when I checked with my meter so I just assumed the fuse for the A/C amplifier was good, and it was, it just wasn't in slot 7 it was in the unused slot between 8 and 9. Stupid mistake that cost me several hours. Don't be like me check you fuse position. After a little more browsing about this problem found I was not the first to do this, give it a check.
Awesome posts, thank you. My wife's 2005 avalon blinks about 35 seconds, nothing works. Stops blinking and ALMOST everything works except heat on passenger side. I will remove the glove box and start following some of what is in here and hope to resolve. thanks again!! Oh, has the times where, as has been said, if the car is restarted soon enough, it sometimes goes right to previous settings, otherwise it is the blink, then to 75 degrees.
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