A/C Light Blinking Troubleshooting Guide

Another success story! I did test my old sensor but it was reading high at 5v.
(Unlike OP who was reading low).
When I passed the magnet negative side the value would drop but when the positive side passed by no significant change.
Thanks OP for a great write up.
Does anyone know why the new sensor has the epoxy on the back.
(The new one has multiple colors)

 

Is there any common leak points on these? I have a 13 model 4.0 that I just got that the air is blowing, the light is staying on and not blinking, the compressor is coming on and so is the clutch, but I’m just getting warm air.

what would you guys do next? Check pressures?

 

If you have a UV light look for dye on the lines, hoses, compressor, condenser, evaporator drain, etc.
Other than that yea need to check pressures and see.

 

So my flashing AC saga is hopefully over. Dealership had the truck 3 different times for the same issue. It eventually ended up being a loose pin in the wiring at the compressor. Not sure if this was the original issue or if it was created somewhere along the way.

 

Another success story I think after years of dealing with the intermittent blinking. Seemed to happen randomly at idle or waiting stopped in traffic and would not happen at high RPMs driving on the highway, only in the high heat months. Replaced the compressor pick up sensor and it’s not happened for 3 days. Was a pain to remove the wiring harness as my 13 had a tan clip on the plug that had to be removed before I could unclip the sensor. Didn’t test the old sensor but definitely remove the front skid for easier access. Thanks!

 

Fish Taco 4x4 I would wait a couple of weeks before declaring victory.

Mine has been acting up for > 3 years, but so infrequently and only when I let it idle and only when really really hot (> 90F). Also press off and on, then works like nothing happened. So last summer I replaced the Magnetic clutch relay. The problem came back like 10 days later when about 101 and idling in front of my garage. It happened a few more times before summer ended. I planned to replace the pickup sensor, but it started cooling off and never happened again until around June 1 of this year. I've been busy, so thought to just pay someone to put on a pickup sensor.

The guy I take my truck to, I asked him to replace the pickup sensor, he said, let's replace the Magnetic Clutch Relay. I told him I already did, but he was not convinced. He put one in for free while I monitor. It has been 3 weeks, no flashing light. He said some of the Magnetic clutch relays sold are junk. He had a brand (maybe OEM) that he trusted. I think I probably got one off off Amazon or AutoZone. So far so good. I really will replace the pickup sensor if it comes back, but pretty hopeful after 3 weeks and this current heat in Texas.