A/C Light Blinking Troubleshooting Guide

HI OP

I got same issue (flashing A/C light) on my 07 Tacoma
(When the A/C light flashing that the clutch is stopped rotating)

May i know how to check the clutch is working normally ?
I tried to rotating it by hand when the car off, it can be turned by hand, is this a normal situation?

Thanks.

 

I posted my full experience in another thread but the issue with my AC light blinking was ultimately my belt tensioner.

I have not had the issue since I changed it even though it didn't really bad enough to change it apparently it was allowing micro slapping of the belt and stuttering of the compressor pulley.

The tensioner has either a spring or gas shock that provides the mechanical tension in the belt and a rubber isolator that dampens high frequency vibration, the dampener wears out before the mechanical pressure so you can have fine belt tension but still need to replace the tensioner itself, not just the pulley.

 

Do you have the part number for the belt tensioner ?

Is this one ?

Part Number: 1662031013
Supersession(s): 16620-31013; 1662031011; 1662031012

 

A few weeks ago the AC light was blinking one one particular drive. Never happened again. Cold air has been weak but it’s also been hot af. Having the system recharged now, it was about 1/4 low.

Worth changing out the relay and/or sensor as a preventive measure? No explanation for the single instance of the blinking.

 

I would save yourself the cost and test the sensor if you can. The relay is cheap if you want to swap it just in case but you will never know if it worked until the issue comes up again and you still won't know for sure if its your relay or something else. My issue was similar to yours and the OP's but after testing the sensor I found it was fine. I hooked it all back-up and made sure the connections were tight and the ground was tight and clean and everything has been great since. The only thing I did change/replace was the relay prior (weeks before) to testing and it made no difference for me since the issue showed back up randomly after the change.

 

I had it in my head somehow that the relay and sensor were both inexpensive parts. Now that I see the sensor is $90 I’ll take your advice and review the instructions to test it. AC seems to be blowing fine since the recharge.

 

My 2006 Tacoma has just started the blinking AC Light. I did hear a funny noise and smelled a burning rubber smell and the cool air went to hot. I have a great relationship with a garage in town and I will take it to them as soon as I can. I think we will be starting with the clutch and belts and all to see how we look and then go out from there. The Guide has given me a lot of info so at least when I talk to my mechanic I will have a good idea of where to start, but I am sure when he hears what happened he will know on his own where to start!

Update when I get this figured out for sure.

 

I've got the intermittent flashing AC light and I have a couple of questions.

The Magnetic Clutch Relay. Part#

$26 90987-02028 Toyota Genuine Magnet Clutch Relay

90987-02028. Since I can see the clutch engaging for several seconds I'm guessing it's good. Can relays have intermittent problems? I see some people mention they pulled another relay to swap and test. My Denso relay is a light grey. The other Denso relays are a light blue and have a different number on them. Does that make any difference, like amp rating? As long as they fit is it OK to try them? I also notice the grey relay is resin sealed and the light blue ones aren't.

The Compressor Pickup Sensor. Pulled it and tested fine. 2.7v which changed with a magnet. There is a little swelling of the plastic on top of the sensor and I thought that may be from something overheating inside but I can see a "dip" in the same spot on the OPs pic and now I think it's probably some deformation left from the manufacturing process.

So relying on the idea the sensor and relay either work or don't work and won't have intermittent problems I'm moving to the other suggestions.

 

Thanks, good test!
On my 2012 it was in the 90's and it was the first time I used it this season. I stopped for about 5 min and when I restarted the compressor clutch appeared to seize, belt squealed, burning belt smell. I shut it off and checked under the hood to see if the belt was on. I started the truck with the A/C off and checked everything without the A/C on first. Then while watching, I had my wife turn it on. The clutch came on so I had her turn it on and off and on again to confirm the clutch was still working.
My original thought was the A/C go too hot and had too much pressure on one side causing it to lock up and when it cooled the clutch was working. Not the case, the A/C light was flashing and no cooling.
There is still refrigerant in the system so that takes me to this post and I am going to test today.
Thanks

 

My 2007 has similar symptoms, including the burning belt smell. For now, to be safe I removed the AC fuse. Don't want to activate it accidently. I'd be interested to see how you make out.

Thankfully this unusually early heat wave is just this weekend with temperatures in the mid 90s. Glad to have the rear sliding window, will help a little bit for now.

 

My 2006 developed the blinking A/C light last fall. Decided to wait until spring to troubleshoot. Tried it a couple weeks ago, it was 90F+ out. It stayed on with no cool air. Long story short, it took out the clutch, compressor and belt. $1655 and change. Upside, I have A/C for Memorial Day weekend and my wife got a extended test drive of a Corolla that she has been eyeing So we now have a Corolla on the way and I have A/C

 

Lol. Sounds like you lucked out getting a good salesperson. Kudos to you.

 

I guess I have an idea what my AC situation is going to cost! Expected $1.000+ Glad you have AC, and another Toyota coming.

I've had some Hondas, but now many models, even the CR-V come with a 1.5L turbo. I wonder how they'll be at 150,000+ miles.

 

Where is the best place to buy a compressor for a 2015. What brand other than Denso is good? Thanks.

 

^

 

From Toyota. Generally speaking, OEM is always the way to go. New is about $210 (no clutch). I think they are Mahle now which replaced the Delphis (in my case).

 

@JCH thank you for being so thorough with your post! I changed my motor mounts and now my AC light is blinking after the compressor runs for a couple seconds. Scrolling through your reasons and I see the sensor... That I unplugged to get better access, and never plugged back in!

 

So I started getting this blinking AC light recently. I thought it was the fuse and since it was a cheap option, I got one but didnt solve the problem.
I then went under the car and found out that when they recently changed my alternator at the shop, they tore off the ground wire from the harness….
lightly touched it back on, turned on and we good to go.
Need to solder it in place now.

 

To the JCH guy that made this post! You are brilliant! I have been trying to figure out this issue for a while and because of your post you helped me fix the issue. Thank you very much! Here is also another great tid bit. Instead of replacing the sensor I just cleaned it and reinstalled it and now it works! No more intermittent cutting off. No more flashing a/c button. This sensor is a hull sensor. It works just like a abs sensor. If the sensors get dirty they can cause intermittent readings and can cause a false signal. This sensor is mounted in the down position. So when you go 4 wheeling mud/dirt gets on the sensor. Even though its mounted to the a/c compressor body. Dirt can still get wedged between the sensor and the body of the a/c compressor. In order to diagnose something I first need to understand how the system works first. This post helped me understand how this system works. Thanks again Justin! Great job!