Case TV450B air conditioner compressor blowing fuse

I recently bought a 2021 Case TV450B with 2100 hours. The air wasn't cooling so I checked the fuse for the compressor and it was blown. Replaced the 25 amp with a 30 which was all I had and it blew. It did blow cold air for a minute until it blew. Has anyone ever had this problem?

Sounds like the compressor is having a bad day.

I'm thinking there is a short in the compressor

Proving the all the electrical is good on the machine the most common issue is the clutch coil goes bad, you'll have to test the coil by unplugging the wire'(s) and doing an ohms test using a multimeter on the coil itself If the clutch coil is bad you can find a local ac compressor shop bring the bad coil with you and they and double check the ohms and help you get the correct replacement, you do not need to buy a complete compressor for thousands of dollars If your coil is good you'll have to start checking the switch and wires going to the fuse box to the compressor Common spot is underneath the fuse box sometimes have bad wire and or connection possibly burnt or wire is touching metal Hope this helps you out

Thank you! Great advice. I will start checking.

Did you ever figure out the issue ?

I haven't had time to look for a short. When it gets hot again I'm sure I'll get to it.

Find out if the fuse that powers it up or the relay that powers it up is loose on one pin. Case has tiny pins on the relays and they come loose over time, of coarse the clutch could be shorting out, but that could be checked with remote power. Simon C

I checked for continuity between the compressor housing and red single wire and there definitely is. When I checked under the cab I couldn't find a problem. It really looked like no one has been under the cab before.

I think the condenser fan runs off that fuse as well, might try UN plugging the fan.

I unplugged the fan and there is continuity between these 2 metal prong connectors. Should there be? I left it unplugged, installed a new fuse and ran it with the air conditioner on. It blew cold for a few minutes and then the air warmed up so I assumed that the fuse had blown again. Checked the fuse and it's good.

DmanD6N said: View attachment 363308 I unplugged the fan and there is continuity between these 2 metal prong connectors. Should there be? I left it unplugged, installed a new fuse and ran it with the air conditioner on. It blew cold for a few minutes and then the air warmed up so I assumed that the fuse had blown again. Checked the fuse and it's good. Click to expand... So in your hand is the plug that feeds the fan, or the plug that feeds the AC Compressor Clutch. Can see the compressor in your picture. Good to check the pins on the AC relay, or Heater Fan cause if one is loose it can take out a fuse after so many minutes. A hard fault to ground is a fuse blown in a micro-second. Loose pins on a relay connector or loose fuse holder can build up heat and blow in 1-10 minutes sometimes. Just wanted you to beware of this situation. Simon C

Thanks!

that would mean either you have a bad condenser fan motor or damage in the wiring to the motor. and the AC will work with that fan UN plugged until the high side pressure gets too high and the pressure switch shuts the compressor off

I took the fan out and the wires were bare right beside the electric motor. The 4 screws holding the motor in place were loose. The motor seems to be a sealed unit so I used black electric tape to seal and keep the wires apart. Didn't have time to try it out today but I'm sure this has to be what's burning fuses.

they almost look melted, the motor could be drawing too many amps. might want to check the trunk t on the wires when you do plug it back in

Tried it out. Not blowing cold so thought the fuse blew but it's good. Ran out of time today to try anything else.

is the compressor clutch engaging?

The compressor clutch is not engaging. Fuse is still good.

Does the light on the switch light up when the AC is turned on? there is a high pressure switch behind the compressor, check for power there. if there is no power on either side is the switch then the issue could be in the HVAC box it's self. there are 2 relays by the blower motor and inside the box there is a low pressure switch and a thermistor.