A/C Light Blinking Troubleshooting Guide

Knowing nothing except I had a blinking light, google search lead me here! Then another search lead me here. https://www.youtube.com/watch?v=j1hcm76NDRk&ab_channel=proclaimliberty2000 Easy fix. Ordered the generic Magnet Clutch Relay to replace the now missing horn Relay. AC back to kicking! Thanks!

 

A/C amplifier

How do you pull this thing? Seems like there is a rivet holding it in place rather than a bolt.

And do you know what year the part changed? Regardless, is the part interchangeable to all 2nd gens, or is it specific to the year(s)? Can't find info elsewhere.

 

Hello MolokaiTacoma, Welcome to the world of Tacos! This sensor that is mounted on the a/c compressor. My sensor was mounted with a 8mm hex head bolt. And there is a phillips on top of that head. Not recommend to use a phillips screw driver because of the angle. It could get striped out. Use a 8mm socket on a wabble joint. But you say that yours is riveted in? I have never seen that before. What year is your Taco? mine is a 2014. I believe that these trucks are the same between the years 07 to 2015. Maybe certain years used rivets. I'm not really sure. Still to this day my a/c works. After I removed the sensor and cleaned it. Before I thought is was low on r134a refrigerant. But it was fine. I also checked the pressures when it was working. Everything checked out okay. It just kept stopped working. and all I was doing was turning back on the a/c until it started stopping and flashing. I delt with this issue for a long time until I found this thread. The sensor is kind of like a fail safe sensor. It will shut off the a/c if there is a issue with the rotation of the compressor. Like if the compressor intermittently freezes.

 

After following this thread for a while, because I was having the same problem, specially when the temp. was above 85f, I changed relay, I took the tacoma to a shop to get the refrigerant charge checked, checked that the cables to the amplifier and compressor were good, lately, as of this year, it was really bad, I had to press the a/c button every 2 seconds for a while until it would work, found out the sensor was tight but I was able to wiggle it with a little bit of effort, I tightened it, and a/c started working again, I guess it was having issues with the ground, and I haven't had any issues since I did that.

 

I've had this issue for the past few years and I've been living with it.

A/C light would randomly blink . Could be 5 mins in, or 5secs in.

Lately it's gotten bad where it'd just blink right away after turning off and on. After a dozen or so off/on, it'll work.

Replaced relay and still same.

I then removed the compressor pickup sensor and tested as per OPs post and it tested good at 2.4 volts. I clean the connector out with alcohol and reinstalled the same sensor.

Strangely enough, I haven't had the issue for more than a week now with over 3 hours of AC usage

 

A few summers ago I had a new AC installed and now I am wondering if it was a “rebuilt” one. I did find out last weekend that the resistor was bad and the blower miter was not replaced either. $1800 for a whole new AC system and it only worked about 6 weeks.

 

On my 2007 - Following this Thread I went through and Replaced the AC Pickup and the Climate Control Computer and checked the Clutch relay, and pressures with a gage set. So the other day on a blazing hot day I pulled up to the store and went in for about 20 miniutes. I came out and the Rearview Mirror Temp was reading over 100 when I started the Taco. I just thought. What the heck. Try the AC. Bingo it works, kept working for the whole day. Today in the morning in the low 80s I started it up and .... Blinky light I returned after my errands and had to unload the truck before parking so let it idle. The Temp on the Mirror read over 100. So I pushed the AC button and bingo AC cuts on and just ran while I finished unloading. So I'm stumped what it could be but it is definitey either pressure, Pressure sensor or something I'm not considering. Any ideas?!

 

I was having this problem. Just had AC compressor kit installed. Everything was working well for about 1 week. Driving home from work, started blinking and cold cut out. I shut off HVAC completely and it seemed to reset. Turned it back on and it was cold again. After 5 minutes, started blinking and same thing. Repeated that 3-4 times before arrived home. Left a VM with my mechanic - any thoughts?

 

I'm having an issue with this intermittently so not sure how to go about testing it and looking for some insight. A few times when I first turn on and blast the AC at idle or slow speed when its really hot (90+ and often humid lately) it will blow warm air and then after 30 seconds or so the AC light will start blinking. If I shut it off for 30 sec or so and turn it back on once I'm moving a reasonable speed it seems to work fine again. This doesn't seem to be an issue when stopping at lights or light traffic when I've already had the AC on during the drive, but I haven't gotten stuck stopped in heavy traffic for too long recently. Between this and feeling like it takes a while for it to blow cold and feeling like its not strong enough, I thought it might be low on refrigerant so I had it evacuated and recharged but it doesn't seem to have helped.

 

Bought this 2013 last September ,so many noises to judge what's okay & what's a potential problem. A/C light started blinking today 106degrees blowing hot air now . Yesterday I left it running to run into a friends house for 10 minutes ,came out was blowing hot air but seemed to cool a little ? Maybe a sensor but read all these great info ideas ! Also took it into Bob's Service Ctr. Spokane, WA. another new bad sound , no idea they said maybe a carrier bearing . Going to leave it all to be checked out ! My 81st Birthday July 19th present I guess $$$$$$$$$$ ! Really appreciate all the info here this is a great go to for me ! THANKS GUY'S

 

Thanks for the thread @JCH

Read through it all, a few people mentioned a noise at the same time as the AC light blinking but I didn’t see an explanation.

I had a mid pitch whistle then the AC cut out, light flashing today. It would be nice to know the reason for the noise and if it helps with the diagnostic.

TIA

 

The flashing A/C light is when the A/C amplifier does not detect a correct speed signal from the compressor lock sensor after commanding the MG CLT relay on.

Possible causes are:
Open or shorted wire(s) in the lock sensor circuit
Bad lock sensor
Internal problem in the compressor
Open control wire between the A/C Amplifier and MG CLT relay
Open in the wire from the MG CLT relay to the compressor
Failed compressor clutch
Belt slipping
Failed A/C amplifier

You said you heard a squealing noise when it quit, that would suggest either the clutch or the belt was slipping.

 

Thank you

 

Be very careful to find an honest professional A/C pro ! I'm going through a nightmare shop that pretends they are skilled at everything & I'm getting hosed $856.00 (Just the compressor alone, no labor for a compressor & don't know if that was really the problem now. It could have been a $5.00 part on up ! They also said my Carrier bearing on my driveshaft needed replacing so I bit on that also . When I drove it home I felt a vibration growling noise & took it back & at first said they were given a bad part but I came to find out they installed upside down so after that I'm not sure all is good? I'm sure there are good honest qualified techs out there but buyer beware , lots of scammers & bill padders. Sorry no real answer just my experience & advice. I went through this with a GMC Sierra also but had a great insurance policy ! A/C repair is for experts only !!

 

Before I go testing everything do you have any input on what it could likely be if I get the light intermittently? I get it only when running the AC during high heat (90-100 here/humidity) when stopped in traffic/lights/parking lots, more likely if I run it on higher fan speeds. Once I'm moving and turn it off/on it will work again, but still doesn't work very well during high heat regardless

 

Cleaning the sensor sounds interesting. If your still around @07Yota209 , how’s it working out in the longer run.

@Peter603Taco , I’d look into cleaning that sensor and also going through the steps in the first post here.

Good luck to you both

 

Being it's heat related my primary suspects would be the clutch coil, MG CLT Relay, or Lock Sensor.

Would need to see when it acts up if the compressor comes on for about 3 secs when the button is pushed and then turns off with a flashing light. If it does then we are likely dealing with a Lock Sensor issue, if it doesn't then we are likely dealing with a bad relay or bad clutch coil.

 

Thank you for the advice, I'll try and see next time it happens, pretty sure it's more than 3 seconds as it will happen if I say leave the truck running with AC on in a parking lot while i talk to someone for 5 min, come back in and its blinking and blowing hot air.

 

I have read all of these pages and we had a 2005 Toyota Tacoma V6 here at the shop and same deal, bad noise from AC compressor and Flashing AC Light, Replaced Compressor with Import Direct from O'reilly and now the noise is gone but the light was still flashing, everything checked out... Relay, wiring, AC Booster all of it. System had no indication of metal in it, we almost gave up and we were going to get a OEM Compressor with the AC Lock switch, I noticed in the notes from the vendor that the OEM sensor had to be swapped over to the new unit and off the old unit that and light went away and the system is working fine.

 

I have read through most of this post after I got the blinking A/C light. For me it starting blinking in the middle of a drive. When I turned the AC off and then back on there was a groaning noise, which stopped and then the light flashed some more. Since then I have not gotten the system to provide any cold air. I thought it might be the lock sensor, so I took it off and tested it. It tested at 1.4V so I ordered a new one. When it came the new one also tested at 1.4V... So I tried mounting it on the truck with the same result as the old one. Today I made sure to get better connections to the prongs in the sensors, and actually got 2.4V, with each reacting to a magnet. Darn! A couple of weeks before I had thought the pressure was a bit low, and used a recharge kit from NAPA. If I put too much pressure in, would that account for the whining and blinking light? I will now put the old sensor back on with a cleaned out connector and try in one more time.