I have Kubota l4200 gst-c with the a/c shorting out. I've replaced the relay. I've unplugged the blower motors, resistor, and thermostat. i have power in to switch but once i turn the switch to any on position I lose my 12v. I've looked all over the internet for a wiring diagram for this model but I've had no luck. Any help would be greatly apperciated.
a/c shorting out
- Thread starter Bsmith8732
- Start date
I thought so too. but when I bench tested it with battery power all switches work as they should.
Generally speaking... if the supply power goes away when the load is switched "on"..... then there is a bad connection FEEDING the power to where you are measuring.
I have said MANY times in the past, the most-efficient way to isolate such a problem is using "voltage drop" measurements with your meter.
I have said MANY times in the past, the most-efficient way to isolate such a problem is using "voltage drop" measurements with your meter.
- If you have schematic, it should take no more than 3 minutes to isolate the source of the problem
- Without schematic... it may take 20 minutes to figure out how it is wired before fixing it.
Sounds like a dead short someplace.
If it were me....I'd disconnect the A/C clutch, run 12vdc directly to the clutch (which is just an electro-magnetic coil) and see if the clutch engages. This will serve to tell you that it is likely OK (or not) and not the source of your problem. With that circuit still disconnected.....try to run the A/C again and see if you lose 12v.
IF you do.... then begin by visually inspecting the wiring in that circuit for chaffing, pinching, rodent damage.
You have either a faulty component, high resistance or a dead short someplace.
If it were me....I'd disconnect the A/C clutch, run 12vdc directly to the clutch (which is just an electro-magnetic coil) and see if the clutch engages. This will serve to tell you that it is likely OK (or not) and not the source of your problem. With that circuit still disconnected.....try to run the A/C again and see if you lose 12v.
IF you do.... then begin by visually inspecting the wiring in that circuit for chaffing, pinching, rodent damage.
You have either a faulty component, high resistance or a dead short someplace.
I would love a schematic right about know. I do believe my switches are good I tested them removed them checked the copper plate inside that makes the connections. all is well with it power went though switch it each with when switched on. I've sent power threw a blue and black wire and activated the a/c button and my blower and compressor were all working. however the blue and yellow wire was grounded and shouldn't be it shows to go to my resistor ( I think) but when I unplugged the resistor it still killed my power when I activated the blower switch. there is a (what Kubota calls) an amp unit the seems to control the system once power is sent threw that blue and black wire. I can hear the relay kicking on in it. I did replace the other relay that gives the switch its power. even though I bench tested it to and it operated as it should.
I will try that. I did send power to the blower on what I believe is the direct wire to the blower bypassing the resistor wires and I turned the cold function on and everything worked on that function, Compressor clutches kicked in and blower came on and was blowing nice cool air. The other 2 speeds though, there my problem.
High speed for fan is often a separate circuit on A/C units and bypasses any resistor/block.
Check over this page from the L4200 WSM which shows the cabin electrics.
Dave
Dave
Well this changes my whole thought process on how i thought it worked. I will update after diag.
I HAVEN'T FOUND THE BREAK YET BUT I HAVE POWER FROM THAT FUSE THROUGH A WHITE WIRE WITH A BLUE STRIP TILL IT GOES IN A PASS THROUGH UNDER THE CONSOLE THAT GOES UNDER THE TRACTOR.
THE WIRE LOOM COMES OVER TO THE DRIVER SIDE (NO POWER) AT THIS POINT. GOES BACK INTO THE CAB UP THE PILLAR OVER TO THE MAIN RELAY. WHAT WAS THROWING ME FOR A LOOP WAS THE HOT ON THE RELAY COIL WAS CROSSING OVER THE COIL TO THE SWITCH SO I THOUGHT THE SWITCH NEEDED POWER BUT IT'S GROUND CONTROLLED. WILL CUT OUT AND REPAIR WIRE OR DO AN OVERLAY. THANKS FOR THE SCHEMATIC AND ALL THE HELP.
THE WIRE LOOM COMES OVER TO THE DRIVER SIDE (NO POWER) AT THIS POINT. GOES BACK INTO THE CAB UP THE PILLAR OVER TO THE MAIN RELAY. WHAT WAS THROWING ME FOR A LOOP WAS THE HOT ON THE RELAY COIL WAS CROSSING OVER THE COIL TO THE SWITCH SO I THOUGHT THE SWITCH NEEDED POWER BUT IT'S GROUND CONTROLLED. WILL CUT OUT AND REPAIR WIRE OR DO AN OVERLAY. THANKS FOR THE SCHEMATIC AND ALL THE HELP.