aux hydraulics switch problems

[Parx10]

I was using a bobcat 753 and was doing some light clean-up work around my property. Everything was going fine, I have a grabber on the front and had just picked up a load of sticks and brush and when I went to dump it I noticed that the grabber wouldn't open. I tried to push the aux hydraulics switch but nothing happened. The arm raises and lowers just fine, it tilts forward and backward, but I can't seem to get the aux hydraulics switch to come on. I don't really know anything about this kind of equipment but I can do some mechanical work. I have searched the web and other forums but I can't seem to find any information about this. Any information that someone would have would be greatly appreciated.

 

[Fishfiles]

I would ask you if the light will light up when you press the aux button , and when you hit the button to close it do you here the sounds of the hydraulic engaging or nothing at all in open or close , if it will close but not open you may have one spool coil bad , it so you can switch one with the other to verify , if you don't anything in either direction it could be the controll head which is on top the drive lever , a wiring problem or rare but possibly a quick coupler problem

 

[Tazza]

I would ask you if the light will light up when you press the aux button , and when you hit the button to close it do you here the sounds of the hydraulic engaging or nothing at all in open or close , if it will close but not open you may have one spool coil bad , it so you can switch one with the other to verify , if you don't anything in either direction it could be the controll head which is on top the drive lever , a wiring problem or rare but possibly a quick coupler problem

Does it make a whistel sound as the oil goes over the relief when you try and grab harder? you sait it won't open, but does it close? it could be a stuck stem in the control block or a bad coil.
If you lift the cab and swap the coils from stems and see if it opens but does not close.

 

[Parx10]

Does it make a whistel sound as the oil goes over the relief when you try and grab harder? you sait it won't open, but does it close? it could be a stuck stem in the control block or a bad coil.
If you lift the cab and swap the coils from stems and see if it opens but does not close.

The LED lights do not come on when I push the button, and it stopped working when I closed it so its all the way closed. I'll check to see if there is a sound when I try to engage it tomorrow and I can check the other things too. Thank you both for your help.

 

[Tazza]

The LED lights do not come on when I push the button, and it stopped working when I closed it so its all the way closed. I'll check to see if there is a sound when I try to engage it tomorrow and I can check the other things too. Thank you both for your help.

If the led does not come on, its not turning on. It could be the controller or wiring. The older ones had a box on the left side mounted to the frame. Check the pins are not corroded and they are seated correctly.

 

[mrfixitpaul]

If the led does not come on, its not turning on. It could be the controller or wiring. The older ones had a box on the left side mounted to the frame. Check the pins are not corroded and they are seated correctly.

don't forget the easy stuff....check the fuses.

 

[taildragger]

don't forget the easy stuff....check the fuses.

Any update? I had the same thing happen to me today on my 763 except with an auger.

 

[TriHonu]

Any update? I had the same thing happen to me today on my 763 except with an auger.

The auxiliary hydraulics are controlled by the Pulse Width Modulator (PWM). This is the electrical controller under the seat attached to the left side of the loader frame.
There is a dedicated fuse for this circuit. The fuse should be marked PWM. This box accepts signals from the switch on the dash and right joystick to control the Aux Hydraulics.
I had a similar problem where the Aux Hydraulics just quit working. I checked the fuse and it looked ok. I checked for power at the PWM box and had nothing. I went back and put a meter on the fuse and though it looked ok, it had no continuity from pin to pin. I replaced the fuse and all was good again.
For my C series I was told the PWM box is about $600 USD. The switch with the two LEDs is about $125 USD.
One LED in my switch quit working, but the switch was still good. When I heard the price of the switch, I removed it from the dash and found the LED leads were badly rusted. I carefully disassembled the switch and soldered in two new LEDs ($1.50) and reinstalled.

 

[taildragger]

The auxiliary hydraulics are controlled by the Pulse Width Modulator (PWM). This is the electrical controller under the seat attached to the left side of the loader frame.
There is a dedicated fuse for this circuit. The fuse should be marked PWM. This box accepts signals from the switch on the dash and right joystick to control the Aux Hydraulics.
I had a similar problem where the Aux Hydraulics just quit working. I checked the fuse and it looked ok. I checked for power at the PWM box and had nothing. I went back and put a meter on the fuse and though it looked ok, it had no continuity from pin to pin. I replaced the fuse and all was good again.
For my C series I was told the PWM box is about $600 USD. The switch with the two LEDs is about $125 USD.
One LED in my switch quit working, but the switch was still good. When I heard the price of the switch, I removed it from the dash and found the LED leads were badly rusted. I carefully disassembled the switch and soldered in two new LEDs ($1.50) and reinstalled.

I have power at the PWM fuse and I put a new one in for the heck of it....still won't light up. I am not even getting the green lights to engage the aux hydraulics, does its power come from the PWM as well? I've checked all the fuses, connections, and anything obvious I can think of. Does anybody have an idea of where else to check? Or how to check to see if the PWM is good? Thanks.

 

[taildragger]

I have power at the PWM fuse and I put a new one in for the heck of it....still won't light up. I am not even getting the green lights to engage the aux hydraulics, does its power come from the PWM as well? I've checked all the fuses, connections, and anything obvious I can think of. Does anybody have an idea of where else to check? Or how to check to see if the PWM is good? Thanks.

More food for thought......I tracked down the hot wire leading to the Controller box....it has 12v coming to it. When I hooked it back up the green light came on when I pushed the button. I disengaged it and tried to reengage it and it would not come back on. I unplugged and plugged the connector five times trying to duplicate it and nothing. I put the meter back on it and hooked it back up and it engaged. I tried to start it but it disengaged when I started and would not engage again. When I say engage I mean the green light comes on when I hit the button. Any good ideas?

 

[TriHonu]

More food for thought......I tracked down the hot wire leading to the Controller box....it has 12v coming to it. When I hooked it back up the green light came on when I pushed the button. I disengaged it and tried to reengage it and it would not come back on. I unplugged and plugged the connector five times trying to duplicate it and nothing. I put the meter back on it and hooked it back up and it engaged. I tried to start it but it disengaged when I started and would not engage again. When I say engage I mean the green light comes on when I hit the button. Any good ideas?

Were you in the seat, with the seat bar down when you tried to activate the auxiliary hydraulics?
If so, were all the lights on the BICS box green?
You should only be able to engage the auxiliary hydraulics if you are in the seat, seat bar down, BICS lights green
OR
if you machine has the "Push to Operate" over-ride button, push it and then try to activate the auxiliary hydraulics.

 

[Parx10]

don't forget the easy stuff....check the fuses.

I checked the fuses today and the one for the PWM was blown. I didn't have any in that size so I'll have to replace it tomorrow and see if that was it. I have been stressing for two weeks about this and it might come down to something as simple as the fuse. I want to thank everyone for their tips and suggestions about this problem. I haven't been able to use my computer b/c I live in Oklahoma and a tornado came through and hit our neighbors all around and leveled a Love's gas station about an eighth of a mile from my house. There is some slight damage to our carport but most everything else is tree damage. We've been out of power for more than two days and this was my first opportunity to check back. I was almost done cleaning up my property but after monday it looks like I got a lot more work to do...lol I want to say thanks again for everyone's help.

 

[Tazza]

I checked the fuses today and the one for the PWM was blown. I didn't have any in that size so I'll have to replace it tomorrow and see if that was it. I have been stressing for two weeks about this and it might come down to something as simple as the fuse. I want to thank everyone for their tips and suggestions about this problem. I haven't been able to use my computer b/c I live in Oklahoma and a tornado came through and hit our neighbors all around and leveled a Love's gas station about an eighth of a mile from my house. There is some slight damage to our carport but most everything else is tree damage. We've been out of power for more than two days and this was my first opportunity to check back. I was almost done cleaning up my property but after monday it looks like I got a lot more work to do...lol I want to say thanks again for everyone's help.

Hopefully thats all it is, the other question is, if it was the fuse, what made it blow?
Glad you and your family are safe though.

 

[Parx10]

Hopefully thats all it is, the other question is, if it was the fuse, what made it blow?
Glad you and your family are safe though.

The fuse fixed it. The aux hydraulics work fine now. Don't know what it was that could have made it blow. I was just picking up loose branches and sticks when it happened so I have no idea. Thanks again for your help.

 

[Skid Steer Guy]

The fuse fixed it. The aux hydraulics work fine now. Don't know what it was that could have made it blow. I was just picking up loose branches and sticks when it happened so I have no idea. Thanks again for your help.

Fuses can get weak and old and just blow best to have a few extra hanging around.