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Recent content by 4lane

  1. 4

    Cat 304C A/C hose size

    It was an 8 and 10. The 8 worked fine. The 10 was super tight - could not get it on all the way but just enough to get some clamps on.
  2. 4

    Where is the ac pressure switch on a Cat 304C?

    Traced the issue down to a guard that protects the high/low lines that had worn into one of the lines. After a hose splice, vacuum, and recharge I’m back in business.
  3. 4

    Cat 304C A/C hose size

    Are these lines standard sizes? Can’t find any info on them (circled in red).
  4. 4

    Cat 304C A/C hose size

    I have a hole in the A/C high side line and another forming on the low side line near the compressor due to a bracket. Anyone know the size of these hoses so I can cut out the bad spots and splice them? This is for a FPK03040 - thank you!
  5. 4

    Where is the ac pressure switch on a Cat 304C?

    I did some tests today. Getting 12v to pin 4, ground to pin 5, ground to pin 3 ( it was 80 degrees out. Since the evaporator temp sensor is new, and the Relay AS Blower Motor passed these tests, and the AC switch sent power to this relay, I focused on the compressor relay and low pressure...
  6. 4

    Where is the ac pressure switch on a Cat 304C?

    How can I isolate testing of the pressure switch and temperature sensor?
  7. 4

    Where is the ac pressure switch on a Cat 304C?

    Extremely helpful and very thankful for this level of detail. Getting a multimeter lead on a pin will be super challenging. These components all sit under/behind the bottom of the A/C panel. I had to take the entire thing apart to pull it out, and flip it upside down to get to the Relay AS...
  8. 4

    Where is the ac pressure switch on a Cat 304C?

    Thank you for that clarity. Now back to my original question, how can I effectively test the Relay AS (Blower Motor) to see if it's faulty or not?
  9. 4

    Where is the ac pressure switch on a Cat 304C?

    On the schematic there is already dedicated "Compressor Relay". The "Relay AS (Blower Motor)" I'm still unsure of what it does. It's labeled "AS" in all Cat parts so it doesn't seem like it's mislabeled, and I see it as tied into the blower motor circuit. Here it is in the AC system:
  10. 4

    Where is the ac pressure switch on a Cat 304C?

    Wire colors don’t entirely match with the schematic, but it seems you are correct. The image above is the low pressure sensor, the evap temp sensor (or thermistor) and the two wire that goes into the relay I pictured are the same color. That relay has a two wire and a three pin to a circuit...
  11. 4

    Where is the ac pressure switch on a Cat 304C?

    I had moved my focus to the AC box in the cab, too. I found a thermistor, and the compressor circuit board relay which I wanted to test in my earlier comment. But in your diagram I see a low pressure switch and a temperature sensor (evaporator), neither of which I found, but I do see this - not...
  12. 4

    Where is the ac pressure switch on a Cat 304C?

    Yes, just as heymccall shows, there is an electrical connection to a switch in the compressor. Are you saying this is the low pressure switch but it's not sold separately?
  13. 4

    Where is the ac pressure switch on a Cat 304C?

    Serial is: CAT0304CHFPK03040 I only see the following components in the AC system. I believe, the thermostat shown here being a thermistor and the diode is the relay I’d like to test.
  14. 4

    Where is the ac pressure switch on a Cat 304C?

    I don’t see it in this system. I did find this 3-pin ‘relay’ which was located in the most inaccessible spot. How can I check to see if this thing is good or bad?
  15. 4

    Where is the ac pressure switch on a Cat 304C?

    AC is not working on my Cat 304C CR. Compressor spins freely, cab switch is good, no power at compressor. I’m looking for the AC pressure switch but can’t find the damned thing by tracing the lines. Help?!
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