A/C Light Blinking Troubleshooting Guide

Was driving in the rain yesterday and after hitting a puddle in the road my AC started flashing. I assumed the belt was slipping. Today I noticed a big low end power loss only with AC on. Engine doesn’t want to rev up with AC on until around 3k rpms. AC still blows ice cold air. Compressor bearing or clutch you think?

 

bearing. for whatever reason Toyota doesn't use a sealed one. the a/c clutch is an entire assembly. there's a post somewhere with the bearing replacement ($30ish/ebay)

 

The infamous A/C light blinking is occurring on my wife's 2015 Off Road. The blinking is intermittent. While the light is blinking the air conditioner and the fan both are working. This blinking condition only occurs at start up. No squealing noises. The serpentine belt appears to be OK. If the air conditioner is turned off and then restarted there is no blinking. Yep, it is really intermittent. Is there a problem with her continuing to drive the truck until I can contact my dealer's service department? My only concern is that if it is the compressor clutch, might the serpentine belt break and leave her stranded.

 

sounds like it's electricial. chase the wires around and make sure you aren't shorting out somewhere. it's also possible the relay is an issue but that might be because of a short. this was my issue and your description is identical. i replaced the relay and the problem went away only to come back. Mechanic finally found it way up and against the engine.

 

When it is blinking the Magnetic Clutch is dropped out so it should not effect the serpentine belt.

The relay he is talking about would be the magnetic clutch relay which is called "MG CLT Relay" in this drawing of the under hood fuse / relay panel.

https://www.customtacos.com/tech.ol...oyewd/06toypdf/ewd/2006/tacoma/f/em01d0up.pdf

 

JimmyK and kasnerd, Thanks much. tguil

 

First post here. This forum has been so good for so long I’ve never had the need to actually ask for MORE info, but alas...

My A/C light is blinking intermittently as well. Been going on a couple months. Turning it off/on/off/on, it will eventually work for a day or two before it happens again. Of course, when I took it to the shop it worked fine. They checked everything, pressures looked good and they couldn’t figure it out. He guessed what it was and replaced the sensor in the dash that controls the expansion valve (I forget the name), but that didn’t solve the problem. He put back the original sensor and refunded me. I replaced the mag clt relay; no luck. I replaced the AC amplifier; no luck. I just tested the compressor pickup sensor per instructions in this thread; 2.7V and voltage increases/drops near a magnet as designed - i.e. no luck. There are no strange sounds coming from the compressor when it’s engaged.

At this point, the only things left are the in-line pressure sensor (the shop said it’s OK) and the clutch and/or compressor. How do I go about identifying if I just need a clutch or should I just replace the whole thing? Would really like to avoid opening the system if it’s just the clutch.

Thanks i’m advance...for this and the last 11 years.

 

I went through all that you did and are going to do but for me in the end it was the AC amplifier

 

I guess this is still an option as well. Maybe a still-present short is messing with my new relay...thanks, kasnerd. I’ll check this next.

 

Remember all those sensors report back to the ac amp then the ac amp tells the clutch what to do. Put jumper"s" in the relay socket and see if your clutch and compressor engage .

 

Well, the AC was working again today, which signifies to me the relay is still good. Because the engine was hot and the plug is hard to get to, I jumped the in-line pressure switch with the engine on and the clutch engages on command. That suggests both the sensor and the clutch are good. There is no play in the clutch/pulley and I can turn the clutch/compressor by hand with resistance I would expect from the oil in the system. Also, I don’t see any sign of the ‘black goo’ others on the forum have seen to indicate a bad clutch.

Amplifier ✔️
Thermistor ✔️
Clutch relay ✔️
In-line pressure switch ✔️
Compressor Pickup sensor ✔️
Clutch ✔️?
Compressor ✔️?

Still lost.

 

you put a multimeter on the speed sensor? The sensor is a pain to remove/reinstall.

 

Yes sir, I did it last night. Measured 2.7V and went up/down with a magnet. I removed the skid and went from below with a small 1/4” socket and an 8mm socket. It wasn’t that bad that way. Only thing I noticed was the little bolt didn’t really ‘break’ free. Maybe it was loose? Idk.

 

damn. inspect the wiring between the relays and the compressor. Because of the location, inspecting/replacing is frustrating and time consuming.

 

Maybe the OP has 2WD? With my 4WD there I couldn’t find the access to this bolt with a philips head from directly below.

 

If there was a short there, would the relay continue to work? When you had your short, would the AC keep working for a few days or would the short kill the relay? Sorry for so many questions.

 

yes. it would work and then start blinking. and the time it took for it to stop working became shorter and shorter until it didn't work at all. I replaced the relay (2x), sensor, clutch+bearing, fuses...

 

i used a 1/4" ratchet after getting it started by hand.

 

Thanks, Gary & Kasnerd. Let ya know if I figure anything out.