753 f series

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dusty

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Aug 9, 2014
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I have a 753 F series bobcat and I just took the control valve off and had Bobcat put a new seal kit in. I reinstalled it and my solenoids won't open up. When I power then separately they work. The fuses are fine. My seat bar works fine. My bics lights are all on correctly. My parking brake works fine. It starts right up. I see no corrosion on the wires.
 
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dusty

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Aug 9, 2014
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Make sure they are clean and grounded good might just be getting old and weak
I have no power to the solenoids can I take the globe plug relay and switch with the brake switch relay to see if that works or aren't they the same. All of this was working fine until I took the control valve off. All I did was unplug the three solenoids.
 

antfarmer2

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I have no power to the solenoids can I take the globe plug relay and switch with the brake switch relay to see if that works or aren't they the same. All of this was working fine until I took the control valve off. All I did was unplug the three solenoids.
While your in there pull check and clean all fuses and relays and connections
 
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dusty

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While your in there pull check and clean all fuses and relays and connections
I switched the relays and it did not help. I checked the fuses and grounds and nothing wrong. There is no power going through the lines to the valve control. There is three of them. The main solenoid and two aux solenoids. Where does that power come from?
 

antfarmer2

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I switched the relays and it did not help. I checked the fuses and grounds and nothing wrong. There is no power going through the lines to the valve control. There is three of them. The main solenoid and two aux solenoids. Where does that power come from?
Not sure but on my 743 there are two fuses up by the key
 

OldMachinist

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Not sure but on my 743 there are two fuses up by the key
Dusty post the first seven digits of the machine serial number and I'll look at the wiring diagram for your machine. You can also add a email address to your profile and I'll send you the wiring diagram.
 
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dusty

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Dusty post the first seven digits of the machine serial number and I'll look at the wiring diagram for your machine. You can also add a email address to your profile and I'll send you the wiring diagram.
Here is my serial number 5158205 - Thanks for your help
 

OldMachinist

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Here is my serial number 5158205 - Thanks for your help
The 2 solenoids on your control valve are for the auxiliary hydraulics. I think your machine has lights that indicate when the auxiliaries are activated. What are these lights doing?
 
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dusty

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The 2 solenoids on your control valve are for the auxiliary hydraulics. I think your machine has lights that indicate when the auxiliaries are activated. What are these lights doing?
My aux button is yellow on the upper right of the cab. It comes on as normal. The three connectors come from the same line and none of them have power.
 

OldMachinist

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My aux button is yellow on the upper right of the cab. It comes on as normal. The three connectors come from the same line and none of them have power.
The power for the solenoids comes from the controls module.
 photo AuxControlModule_wiring_zpsba06d176.jpg
 

Tazza

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The power for the solenoids comes from the controls module.
There should be a control box on the right side of the frame down low, looking from the bucket, ensure the connections here are good. This is the module that controls the aux hydraulics.
The thing is, i believe is connects to the lights on the dash, so it sounds like it is working, but check it anyway. Even check the connectors at the base of the control lever.
 
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dusty

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There should be a control box on the right side of the frame down low, looking from the bucket, ensure the connections here are good. This is the module that controls the aux hydraulics.
The thing is, i believe is connects to the lights on the dash, so it sounds like it is working, but check it anyway. Even check the connectors at the base of the control lever.
Tazza - Old machinist and everybody. I am going to try to explain this better. I took the control valve out, took to Bobcat mech. He put an o ring kit in it to stop a leak. He tested the main solenoid. It is working. This is the one that opens the oil flow so I can move my arms and tilt. I have no function. It tries to move but can't. There are three connections to the valve box. No power to all three. Also, the solenoid behind the brake solenoid doesn't seem to have any power either. My bics lights are all green, when I lift my bar in the cab it shuts the bics off like it is suppose to. My green button by the key switch works. You can hear the brake solenoid open. I can move the machine freely just no hydraulics. Can it airlock and cause this problem?
 

antfarmer2

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Tazza - Old machinist and everybody. I am going to try to explain this better. I took the control valve out, took to Bobcat mech. He put an o ring kit in it to stop a leak. He tested the main solenoid. It is working. This is the one that opens the oil flow so I can move my arms and tilt. I have no function. It tries to move but can't. There are three connections to the valve box. No power to all three. Also, the solenoid behind the brake solenoid doesn't seem to have any power either. My bics lights are all green, when I lift my bar in the cab it shuts the bics off like it is suppose to. My green button by the key switch works. You can hear the brake solenoid open. I can move the machine freely just no hydraulics. Can it airlock and cause this problem?
Does it have a service switch is it on
 

TriHonu

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Does it have a service switch is it on
Are you absolutely sure you put the wires back on the correct solenoids?
If you mixed them up, you could have a set of wires from the Aux attached to the main hydraulic solenoid.
Without engaging the AUX controls, one set of the three should have voltage when you are in the seat with the seat bar down. That set must be connected to the solenoid for lift/tilt.
If one of the connections for the Aux is connected to the lift/tilt solenoid, you would only get lift/tilt functions by engaging the appropriate Aux function.
----------------------------------------------------------------------------------------------
The box that controls the aux hydraulics is the Pulse Width Modulator (PWM).
If the Aux control wires are connected to the Aux solenoids and the Aux is NOT working:
You should check the connections on the module as well as the PWM fuse in the fuse block.
I would also check for aux function in both momentary and constant flow modes.
Activate momentary flow and try the RH middle rocker switch.
Activate constant flow and try the RH trigger switch.
If neither works, odds are the PWM controller is bad. If one works and the other doesn't, you probably have a bad switch or broken wire to or from the switch.
 

OldMachinist

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May 24, 2006
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Are you absolutely sure you put the wires back on the correct solenoids?
If you mixed them up, you could have a set of wires from the Aux attached to the main hydraulic solenoid.
Without engaging the AUX controls, one set of the three should have voltage when you are in the seat with the seat bar down. That set must be connected to the solenoid for lift/tilt.
If one of the connections for the Aux is connected to the lift/tilt solenoid, you would only get lift/tilt functions by engaging the appropriate Aux function.
----------------------------------------------------------------------------------------------
The box that controls the aux hydraulics is the Pulse Width Modulator (PWM).
If the Aux control wires are connected to the Aux solenoids and the Aux is NOT working:
You should check the connections on the module as well as the PWM fuse in the fuse block.
I would also check for aux function in both momentary and constant flow modes.
Activate momentary flow and try the RH middle rocker switch.
Activate constant flow and try the RH trigger switch.
If neither works, odds are the PWM controller is bad. If one works and the other doesn't, you probably have a bad switch or broken wire to or from the switch.
Okay, so you have the control valve with the BICS valve attached to the top of it. The hydraulic lock solenoid valve is the one on the BICS valve. The lock valve is controlled by the BICS box. The wiring connector that should be connected to it has solid dark green and black wires.
 
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dusty

Member
Joined
Aug 9, 2014
Messages
11
Are you absolutely sure you put the wires back on the correct solenoids?
If you mixed them up, you could have a set of wires from the Aux attached to the main hydraulic solenoid.
Without engaging the AUX controls, one set of the three should have voltage when you are in the seat with the seat bar down. That set must be connected to the solenoid for lift/tilt.
If one of the connections for the Aux is connected to the lift/tilt solenoid, you would only get lift/tilt functions by engaging the appropriate Aux function.
----------------------------------------------------------------------------------------------
The box that controls the aux hydraulics is the Pulse Width Modulator (PWM).
If the Aux control wires are connected to the Aux solenoids and the Aux is NOT working:
You should check the connections on the module as well as the PWM fuse in the fuse block.
I would also check for aux function in both momentary and constant flow modes.
Activate momentary flow and try the RH middle rocker switch.
Activate constant flow and try the RH trigger switch.
If neither works, odds are the PWM controller is bad. If one works and the other doesn't, you probably have a bad switch or broken wire to or from the switch.
when i am sitting in the seat, i get power to aux solenoids by working the switches. I can hear them try to work. still no power to the bics solenid.now what?
 

OldMachinist

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May 24, 2006
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2,748
when i am sitting in the seat, i get power to aux solenoids by working the switches. I can hear them try to work. still no power to the bics solenid.now what?
If the valve light on the BICS controller is coming on trace the dark green wire back to the BICS connector and see if you have power there with the light on.
 photo Hydraulic_lock_solenoid_wiring_zpsea11c896.jpg
 

OldMachinist

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Joined
May 24, 2006
Messages
2,748
If the valve light on the BICS controller is coming on trace the dark green wire back to the BICS connector and see if you have power there with the light on.
Forgot to mention that the output from the BICS controller is less than the machine system voltage. I can't remember exactly but its somewhere between 5-10 volts.
 

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