AC Light Lights up, No AC Idle Up, No Clutch Engagement

[mwebfj60]

Over the Winter, the 30A breaker blew. Reset and it blew one more time. Disassembled blower motor and cleaned windings and such...no further issues. Last Summer..aka October here in Cali...the AC worked fine.

Now, went to check AC system as Summer's on us...the AC button lights up but the AC idle up doesn't engage nor does the compressor clutch. 12V is leaving on the Yellow wire from the AC switch. I can jumper the connector on the A/C amplifier Yellow to Black/White and the clutch will engage when AC button is pressed. Makes sense as it's just a straight shot at that point. I'm not sure of coolant levels but the AC idle up should still engage even if that's the case right?
The blower motor works fine on each of the 4 speed settings. I'm guessing it's the AC amplifier but would like to hear suggestions? Other troubleshooting steps?

 

[3_puppies]

when you had the clutch engaged and running did you get cold air?

my guess is you are low on refrigerant, there is a safety in the system so when it is low it doesn't work and burn up the compressor.

 

[mwebfj60]

It started getting cold, I didn't run it long as it was jumpered.

 

[mwebfj60]

when you had the clutch engaged and running did you get cold air?

my guess is you are low on refrigerant, there is a safety in the system so when it is low it doesn't work and burn up the compressor.

Even if the compressor doesn't kick on, the AC idle up will engage no matter what right?

 

[LAMBCRUSHER]

I thought it should... I also thought the light wouldn't come on unless it had system pressure...but I am wrong a lot.

 

[3_puppies]

I also thought the light wouldn't come on unless it had system pressure...but I am wrong a lot.

mine lights up when it is pushed, whether the comp is engaged or not. I'm dealing with a 62 series.
unsure of the idle up.

 

[mwebfj60]

I ended up putting in another AC amplifier, when I pushed the AC button with fan on, AC idle up engaged and stayed up for about 10 seconds then AC idle up would kick on and off, cycling the RPMs up and down on about a 2 second cycle. Shut it down and took it in. AC shop said it was low. Charged it up and its working fine.
So I am saying my AC amplifier was bad and the low refrigerant level was triggering the Low pressure and causing the cycling. Still unsure if the AC idle up kicks on independently from compressor logic. When things slow down, I will dig deeper into the schemo and break the DMM out to experiment.

 

[Trollhole]

Just a heads up. The Idle up and clutch get the same signal from the same black - white stripe wire coming out of the A/C amplifier.