Faulty, Low Pressure Warning Lights Illuminated

   / Faulty, Low Pressure Warning Lights Illuminated #1  

bindian

Super Member
Joined
Feb 10, 2007
Messages
8,364
Location
Willis, Texas
Tractor
Mahindra 6520 4WD
My faulty and low pressure warning lights, just right of the green healthy light on the upper panel, came on yesterday evening. These lights are hard to see, as the top of the steering wheel blocks them from me. I noticed they were on. But my low oil pressure light was out.:confused: I knew I was a few hours over oil change time, so I parked the machine. This morning I picked up a new filter and Rotella T oil. I checked the hour meter and it read 1112.2 hours. This put me 18.8 hours over the 200 hour recommended owner's manual scheduled change. So I was kinda worried, as I felt good it was only 18.8 hours over.

So I changed the oil and filter and the lights came back on, after the healthy light went out. But this time the low oil pressure light was on, the one with the little oil icon. Now I was really in panic mode.:eek: Even being an aircraft mechanic for 38 years, I still panic when it is my own machine or vehicle.:eek: Then experience kicked in, after I realized it wasn't the end of the world if the oil pump was bad. I looked over the troubleshooting charts, and went back out to look for the oil pressure transmitter. I was hoping it was a bad connection or transmitter. The connector seemed a little loose, so I cleaned it with contact cleaner and reconnected. No more warning lights, just the healthy light.
So I lucked out.:D I was already trying to figure out how to remove the backhoe and loader without running the engine, thinking the worst.:ashamed: Oh yeah...........some healthy prayers were involved also.:thumbsup:

Seems most my problems on the 6520 are loose connections.
hugs, Brandi
 
   / Faulty, Low Pressure Warning Lights Illuminated
  • Thread Starter
#2  
Well................it came back on. I crimped the connector some and still get intermittant lights and the buzzer. Sometimes I wiggle it and all goes out. Sometimes I have to pull the connector, wait for the buzzer to quit, then reinstall the connector. Guess I need to get a new connector. Maybe even a new pressure switch.
I gather it has been working itself loose for awhile and just now decides to be an intermittant gremlin.
hugs, Brandi
 
   / Faulty, Low Pressure Warning Lights Illuminated #3  
Keep it up Sis, and all us electricians will be unemployed... [ all this, and you shoot, too....!!!!!!!!!!!!!!! :) ]
 
   / Faulty, Low Pressure Warning Lights Illuminated
  • Thread Starter
#4  
Keep it up Sis, and all us electricians will be unemployed... [ all this, and you shoot, too....!!!!!!!!!!!!!!! :) ]

Hehehe. You are Sooooooo funny.:rolleyes:
hugs, brandi
 
   / Faulty, Low Pressure Warning Lights Illuminated
  • Thread Starter
#5  
Can an installed oil pressure transmitter be tested with an ohm meter. Engine running and engine off?
hugs, Brandi
 
   / Faulty, Low Pressure Warning Lights Illuminated #6  
Yes, generally, there should be continuity when the engine is off and none when it is running and has oil pressure (IE: its a normally closed pressure switch).
If its buzzing when unplugged, I would guess that your wire got chafed and is grounding out somewhere along the way back to the instrument cluster.

Aaron Z
 
   / Faulty, Low Pressure Warning Lights Illuminated
  • Thread Starter
#7  
Yes, generally, there should be continuity when the engine is off and none when it is running and has oil pressure (IE: its a normally closed pressure switch).
If its buzzing when unplugged, I would guess that your wire got chafed and is grounding out somewhere along the way back to the instrument cluster.

Aaron Z
Thanks AZ. It buzzes, I pull the connector off and after a couple of seconds............it stops buzzing. Sometimes it buzzes again when I put it back on, sometimes it does not buzz. This is while it is running. I'm now thinking the wire is loose inside the connector enough to be intermittent.
hugs, Brandi
 
   / Faulty, Low Pressure Warning Lights Illuminated #8  
I would find the other end of the wire, disconnect it both ends and test for continuity from the wire to ground.
If there is continuity with the wire disconnected at both ends, the wire is bad.

Aaron Z
 
   / Faulty, Low Pressure Warning Lights Illuminated
  • Thread Starter
#9  
I would find the other end of the wire, disconnect it both ends and test for continuity from the wire to ground.
If there is continuity with the wire disconnected at both ends, the wire is bad.

Aaron Z
Uh...........you mean disconnect the wire at both ends and hook them to an ohm meter, right? When a wire is good, there is continuity. After checking with an ohm meter on the pressure transmitter, the resistance is the same running and not running. So looks like a new oil pressure transmitter is in order.
hugs, Brandi
 
   / Faulty, Low Pressure Warning Lights Illuminated #10  
Uh...........you mean disconnect the wire at both ends and hook them to an ohm meter, right? When a wire is good, there is continuity. After checking with an ohm meter on the pressure transmitter, the resistance is the same running and not running. So looks like a new oil pressure transmitter is in order.
hugs, Brandi
Sounds like there is at least a bad sender then.
As for the wire, I meant checking to ground to see if the wire has the insulation chafed away and is shorting to ground.
That is the most likely reason for the low oil pressure light/buzzer to stay on after you have disconnected the wire from the oil pressure sender.

Aaron Z
 
 
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