A/C clutch will not engage from A/C switch, but will when direct from battery to clutch terminal

As it says above. Did the swap the relay test. It's not the relay. Clutch coil ohmed out at about 7.5, which is high. But clutch clicks and moves good with a hot wire from the battery. Interior switch is not blinking. Wonder if that clutch plate surface can be worn down to where it is not making good enough contact to grab when it engages ?? Freon was good and it was working great then suddenly stopped.

 

Not sure if this thread will help but I'll be watching:

https://www.tacomaworld.com/threads/ac-clutch-failure-how-to-fix-blinking-light-squealing.448009/

 

Might consider checking the switch continuity.

Seems like everything is in order except the switch. Focus there, not on the clutch.

 

7.5 Ohms is very high for a clutch coil. It should read between 3 to 5 Ohms.

Light Green wire is from the IG1 No2 Fuse 10 Ampere.

I do not know what clutch switch Knute is referring too. But you checked the relay by swapping it. Did you verify that you are getting a ground at terminal # 1 on the relay when the clutch should engage? The AC Amplifier switches the ground on and off, If you don't get a ground it will never work.

Edit: Corrected terminal number.

 

Thanks everybody. I will take a look at these ideas.

 

Check the pressure cutoff switch. Even though you said the refrigerant was good, the switch could be bad. Check the pressure first, Reinstall relay, jumper the pressure switch, and see if the clutch picks up.

 

Usually I can force a clutch to work a few times with straight power but it's likely your clutch.

With the engine off see how the clutch feels to turn by hand.

 

OP, for sure check the refrigerant pressure switch listed in @caribe makaira's list above^^ in Post 6. The pressure switch detects very high or very low pressure and will not allow engagement. The switch is on the passenger side refrigerant pipe coming out from the condenser at the very front of truck heading back to the firewall. I will check for its parameters and post back.

 

the ground to relay should be at terminal 1 no? You will still have some voltage drop across the relay coil, if the relay is pulled I wouldn’t expect to measure ground (0V) at terminal 2, I would check for it at IA1 terminal 31

 

I had an issue where the connector was loose and worn on my Ford and would cause intermittent connection as the engine vibrated and would cause the clutch to drop out, ended up replacing connector with new. If pressure is good the switch should be closed.

 

I was just about to post that same link but you beat me to the draw. The pressure switch is often overlooked IMHO.

 

Yes I misspoke when I said terminal 2. I should have said terminal # 1.

Good catch thanks!

 

YOU GUYS ARE AWESOME. I'M CHECKING ALL THIS OUT. THANKS

 

I was pulling my hair out in a similar situation. I did not know that the clutch kicking on was dependent on refrigerant, I assumed my clutch or compressor was bad because jumpering the relay made it work.

 

THANKS AGAIN Y'ALL. IT'S STARTING TO GET WARM HERE IN ATLANTA, GOTTA GET THIS DONE. CLUTCH STILL JUMPERS ON FROM A BATTERY HOT WIRE EVERY TIME. BUT FROM WHAT YOU SAY THAT COULD BE A FALSE ALARM. HOW DO YOU JUMPER THE PRESSURE SWITCH ?? ALSO, GONNA CHECK THE INTERIOR A/C SWITCH BUT IT IS A SEALED UNIT WITH TWO LARGE PLUGS IN THE BACK. DOES ANYONE KNOW WHICH WIRE COLORS IN THOSE PLUGS TO JUMPER TO BY PASS THAT MAIN LIGHTED A/C SWITCH ?? I HAVE ALL OF THEM LABELED. ALSO THE BLOWER RHEOSTAT COLORS BECAUSE THAT HAS TO BE IN THE "ON" POSITION TO ACTIVE THE A/C SWITCH. I STILL DON'T THINK IT'S THE CLUTCH. HELP !!! AND THANKS...

 

See the PDF in Post # 11 it tells you how to bypass the pressure switch.