A/C Light Blinking Troubleshooting Guide

Have you checked the compressor clutch to see if the rubber separated or the compressor locked up?

 

Thank you for your quick response. I have watched as someone else turns on the AC to see what the clutch does. It is stationary when the engine in running and then when someone turns on the AC it will spin for a few seconds and then disengage again. Someone earlier in the thread saw that the inner and outer parts of the clutch plate were not moving together, but both seem to be moving in unison on my truck. By the way, I did just reinstall the lock sensor with cleaned contacts and it still will only engage the compressor for a few seconds. I did not notice the groan like before (which was not every time anyway).

 

Interesting, you may check the Lock Sensor voltage when you turn it on at connector IH1 (Pin 10 (Red/White)) behind the glovebox to make sure the wire isn't broken but it would seem that either the sensor is faulty or the compressor has failed internally.

Have you tried turning the compressor clutch by hand to see how it feels?

 

So I investigated the clutch some more, and I put paint marker on it in a few places and turned the car on. I could clearly see that the inner part would jerk a bit but then stay still even though the outer part engaged with the friction plate and was spinning. I suspect that the groaning I was hearing was from the torn rubber between the two parts rubbing together. I ordered a new aftermarket clutch plate, and hopefully that solves the issue! I just hope it is not impossible to remove without dismantling a lot of stuff. It is the 2.7L 4X4.

 

Shouldn't be terrible to change although access isn't the greatest, be sure to retain the shims behind the clutch face as they are required to get the correct air-gap.
Here's a video outlining changing it.
https://youtu.be/mB9z4Mnw_iQ?si=eVeuV8PtT1ny19vQ

 

2013 with 177k miles here. Just started having intermittent AC issues over the last couple weeks. Usually seems to happen when it's very hot outside and I'm in stop and go traffic. I've been able to reset it each time it happens (probably 15-20 times so far) by turning off AC and turning back on. Did a long road trip last week (8+ hours each direction) and had no issues whatsoever. Back in town and it's acting up again. AC blows very cold otherwise. No noises or smells.

I replaced the magnetic clutch relay and that didn't solve anything. Should I replace the pickup sensor next? Trying to figure out my course of action here. Any help would be appreciated!

 

Have you gone through the steps in the first post here?

 

I have the exact same issue, check back a few posts to see DM93's advice to me for testing. I haven't been able to get time to yet but please follow up in this thread if you figure it out!

 

This may or may not be related but I’m new here lol my a/c light blinked, I turned it off and back on and finished my drive home of about 15 minutes. It never flashed again but periodically it would turn to warm air and the engine would overheat slightly then come back down and the a/c was cold again. It stayed cold longer than it was warm but the temperature gauge would go up every few minutes. Not sure where to start really

 

First thing I'd do is check the coolant level in the radiator (not just the overflow bottle) with the engine cold and inspect the belt drive.

 

The radiator is full of coolant, coolant and oil both look clean. I’m going to wait for it to happen again and check the line from the engine to the radiator and see if it’s hot or not. Thats about all I know what to check. As far as belt drive, am I looking for it slipping over the compressor?

 

The issue is solved! Clutch now engages and disengages. I dropped the extra shims, and in will now just BARELY turn a smidge every few seconds when the magnet is off. I am hoping that this is not an issue, and will go away as the clutch wears. I DO have another issue though. I was not as educated about A/C systems a month ago, and I overcharged it. I am wondering if that was a contributing factor to the clutch failure? The low side is reading about 100/110psi while running. I called around and so far the only shop I found that will pull out the excess charges $260 to evacuate it, whether they refill it or I refill it. The A/C still runs, but should I evacuate it because it can harm the system?

 

Are you certain on those pressures? It shouldn't even be cooling if the low side pressure is that high with the system running.

Normal low side pressure is typically 30-50 psi depending on ambient and cabin temp.

You really need to be looking at both high and low side pressures to check an A/C system, even that's not an ideal way to determine charge level but you can get close enough typically.

 

I used a set of manifold gauges to test the pressures. It was a little confusing that you turn the knobs on the car valves clockwise to open, and the ones on the gauges anti clockwise, but it made sense when I thought more about it. That reading is from when all four knobs were open, I was seeing pressure in both high and low gauges. It is possible that I messed up how I read them, but I'm pretty sure I am right. Both needles (definitely the low side, pretty sure about the high side) migrated while the car was running and the A/C was on. I will try to take pictures and post them.

EDIT: If the pressure IS that high and I continue to run it would I damage things? If that is a false reading I guess it would be safe to assume that the system would only let itself run within acceptable pressure ranges: So if it is running everything is fine?

 

You need to have the valves on the gauges closed when checking it and the hose ends screwed down just enough to depress the valve in the fitting.

 

OK! so basically by having both valves at the manifold open I was letting the high side affect the low pressure gauge? I hooked it all back up and did as you instructed and then I was getting about 100PSI for the high and about 25PSI for the low. Yay! Thank you so much Dm93 for your knowledge and responsiveness, I couldn't have done it without you! I guess that my "overcharged" system is actually a little undercharged.

 

Thank you for this great information. On my way to Toyota tomorrow for the 6th time with this a/c. 2000.00 later and still the same problem. I'm going to have a chat tomorrow. Most of the parts suggested for this problem have been replaced. I'm done being a ginny pig. Lol

 

Here are the pictures I promised. First two are of the failed clutch and the new one. On the old one notice that the hard rubber is separated from the inner disk in the lower left side of the second picture.

The other picture is from the set of gauges once I figured out how to actually use them right!

 

What's the ambient temp? Those pressures are pretty low.

 

The temperature was like 78ºF