Blinking AC dash button

elmariachi on Mon July 30, 2012 8:31 PM

Year: 2003
Make: Toyota
Model: Sequoia
Engine Size: 4.7L
Refrigerant Type: 134R

The AC button on the dash of my 2003 Sequoia has starting blinking. When I press it on it will start to blow cold air but after about 5 seconds it will start to blink on and off and the cold air will stop blowing (air continues to blow). I've searched the web and found two likely causes the ac compressor clutch and the Magnetic Clutch relay. Several post I found said to take out the relay and tap it on a hard surface to get it "unstuck". This didn't help in my case. I also swapped out the mag. clutch relay with others found in the various fuse boxes. None seemed to fix the situation.

I then swapped out the clutch hoping this would fix my problem. No luck there either. The problem still persists as usual. I can hear the clutch kick in but after a few seconds it disengages and doesn't come back on.

I changed the relay and still no luck. Anyone else have any ideas? Everything on the net says it's the relay or clutch and having changed both it still doesn't work. Will blow cold air for a ~6sec then the light starts blinking. I'm hesitant to change to compressor since it does blow cold air. The compressor spun freely when I was changing the clutch so I don't think it's a seized bearing.

Does anyone have an idea for a new area to look at. The ac does blow cold air. If I keep pushing the button back on after it starts to blink it will blow cold air, but as soon as the clutch disengages it will start to blink again. This gets old pretty fast. Sometimes after doing this a few times it will fix itself and stay on until we shut-off the car. I guess there is a possibility that the relays I swapped in are going bad too, but there doesn't seem to be a problem in those components they (i.e., the horn, fog lights, etc.)

mk378 on Mon July 30, 2012 9:34 PM

Make sure the fuse is tight. Check the fuse and relay sockets in the fuse box for any signs of melting or burning.

It could also be slipping of the belt, slipping of the clutch, bad compressor rpm sensor or wiring, or bad A/C amplifier (which in 2003 I would assume is built into the control panel).

GM Tech on Mon July 30, 2012 9:45 PM

bad rpm sensor in compressor

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

elmariachi on Tue July 31, 2012 12:17 AM

Quote
Originally posted by: mk378
bad compressor rpm sensor or wiring, or bad A/C amplifier (which in 2003 I would assume is built into the control panel).

Quote
Originally posted by: GM Tech
bad rpm sensor in compressor

Is there any diagnostic I can run or I am better off taking it to an AC shop?

Edited: Tue July 31, 2012 at 12:18 AM by elmariachi

elmariachi on Mon August 06, 2012 9:57 AM

Quote
Originally posted by: GM Tech
bad rpm sensor in compressor

Is the RPM / Lock-out Sensor built into the compressor?

GM Tech on Mon August 06, 2012 10:25 AM