A/C Light Blinking Troubleshooting Guide

Ok, so I've been on this thread for some time now. I have that annoying a/c blinking light, 2012 Toyota Tacoma Prerunner V6 2 wheel. I brought it to my shop, and they said no power was going to the speed sensor. So I went and spent the 150 bucks for an a/c amplifier, and I plugged it in before taking the old one out (which looks like a PIA), and the blinking light is still there. I don't think my shop tested the speed sensor correctly. Any input would be great, thanks

 

Does the compressor come on for a few seconds before the light starts flashing or does it not come on at all?

 

To be honest with you, I never checked and just trusted their word. I can try and see if I can make it from inside the truck to the outside and check

 

Need to check that first as that determines the diagnostic path we take.

 

Ok so it doesn't look like it kicked on at all. I could see a number and when I started my truck and put the AC on it did not move at all

 

Should be able to hear it when you kick it on, does the engine speed up a bit when you turn it on?

 

No it doesn’t

 

Interesting, so no compressor action or change in engine speed when the A/C is turned on but the A/C light fladhes?

 

Yep and I already bought a new ac amplifier and plugged it in and still blinking so left the old one in

 

That's a new one, I would expect the engine to idle up when the A/C is turned on.

Well let's check things at the MG CLT Relay, do you have a test light?

 

Nope and I can’t find my multimeter right now annoying, but I did already replaced that too

 

Grab you a test light so we can check what we're missing at the relay socket.

Test light connected to battery Ground check for power on Pin 2 & 5 of the MG CLT Relay with the key on.
Then test light connected to battery Positive check Pin 3, it should light up if the wire is continuous to the clutch coil and the coil windings are good.

If that all tests good then with the light still connected to battery Positive start the truck and have an assistant hit the A/C button while you hold the light on Pin 1 of the MG CLT Relay, it should light up briefly until the light starts flashing.

 

I will for sure try this out this weekend. I don't have someone who can help at this moment, also stupid work getting in the way lol. Thanks for the help and I will let you know