I have a 753F series Bobcat skid loader. Was using it and parked it. Started it back up...Connected the bucket and then it would not move. Its acting just like it does if you forget to take the parking break off. I noticed it was doing that earlier in the week. Id shut it off restart it and all was fine. It does not have the boss control panel. If I start it I can hear the pop noise. Then a few moments later it pops again. if I start it up and hit the traction lock button and work the foot controls I can get them to work. But they will stop working after a few moments as well. On the control panel there's a traction lock override but its just a symbol of the seat bar in the up position (I'm not sure what that does?). I raised the cage and unplugged where the foot brake plugs in. I plugged a paper clip in to bypass the foot brake and that didn't work. I checked all the fuses and there good. There's talk of checking the relays but I have no clue at this point where they are? Just behind the seat there's green lights. The traction lock is blinking..3 fast blinks. After a while there's another one labeled valve I think It starts blinking 3 times as well. Any thoughts on what's going on? Its blocking my driveway and I cant move it?? Thanks
Very common problem......My best guess is the ground from the brake solenoid and the BICS coil on the valve is bad. Both solenoid grounds are tied together in the mainframe harness around the area of the brake solenoid. I'd run a new ground wire from the splice all the way back to the battery. Solves the problem most of the time. Also check all the ground connections at the battery while you are there
Well I installed the new traction lock solenoid. Rats! That didn't work...Still locked up. When I had the solenoid block removed of course it will then drive. And the lift arms work for a bit then they lock up as well. HHMM?? Its flashing 3 times on the traction lock. Should I take the parking brake assembly out and inspect all that? You say a ground problem? So should I tap into the black wire on the traction lock solenoid and run it straight to the battery? Oh its an F series 1999 bobcat 753. What doe bics stand for and where is the bics coil?
BICS = Bobcat Integrated Control System. 3 flashes on traction lock LED is traction lock hold coil circuit short to ground. Not likely the new traction lock coil is shorted out, but not impossible. Can also be a faulty BICS controller or the wire that goes from the controller to the traction lock hold coil is shorted to ground somewhere along the path, most likely suspect.
hold coil short to ground..... i'm still betting it's a bad ground since both the traction lock and bics lights are flashing
Hold coil? bics controller? Are these parts? Iv learned what the traction lock solenoid is and where it is. Iv replaced it. But these other two items your talking about I have no idea where and what they are or where they are located. I'm a pretty good wrench but i'm not to good with the terminology of my skid loader. I just got it six months ago and this is the first issue iv ran in to with it. I know its a simple fix but locating it is the hard part. I pulled out the entire brake pedal assembly. Unbolting it from the floor to disconnecting it at the plug under the cab. Im wondering if the switch at the parking brake pedal is faulty? Is that one of the things your describing?
BICS is not a component, it's a system of components and electronics that are all a part of the Bobcat Integrated Control System (BICS). The BICS controller, the traction lock solenoid, and the BICS hydraulic lock valve on the main hydraulic control valve are all part of the BICS "system". The foot pedal parking brake switch won't be your problem, that circuit isn't directly connected to the traction lock solenoid, it's simply two wires, one comes from the BICS controller and the other goes back to the BICS controller with a switch in the middle of the two, it's simply sending a signal to the BICS controller to turn the traction lock solenoid on/off. The traction lock solenoid has two different coil windings inside of it, pull coil and hold coil. The pull coil has a high magnetic capacity to initiate pulling the solenoid spool in (white wire at solenoid), this winding is powered up by the brake relay which gets it's signal from the BICS controller, it only stays powered up for a few seconds, long enough to "pull" the solenoid spool. The other winding inside the traction lock solenoid is the hold coil (red wire). It gets its signal directly from the BICS controller, that's the wire/circuit that is flashing a code on your BICS controller. The other BICS component is the BICS hydraulic lock valve on the main control valve. It gets its signal directly from the BICS controller.
the traction lock is a 2 part coil, "pull" gets its power from the fuse and relay, "hold" is powered by the BICS the BICS is the black box with all the flashing lights on it behind your right elbow... at the brake solenoid, mainframe harness side, pull back the convoluted tubing and find the cluster of 3 or 4 ground wires spliced together, ( usually within 6 or 8 inches of the connector. cut the splice reconnect everything AND run an additional ground wire all the way back to the battery. 99% of the time this will solve the problem. the BICS coil is located on the control valve, kinda centered between all the tubelines and fittings. the brake and bics have 1 thing in common, the ground wire. early BICS sometimes would lead you off in the wrong direction trying to diagnose using the flash faults
True that, kinda like early OBDI on vehicles, gives you just enough information to leave you scratching your head. Thanks for jumping in about the ground wire circuit crewchief, I yield to your experience on that one.
Now this is good info! Its all starting to make sense to me. First thing tomorrow morning ill go ahead and do this. I did test the parking brake switch. Its fine and has the proper continuity. Ill clean that up real good, get those exposed wires taped up real good and re-install it. Should I solder all those ground wires together or use the appropriate wire nut and electrical tape? My gut says this will work....Thanks for all your great advise. I really appreciate everybody hanging in there with me.
i would solder and heat shrink, or use an insulated butt connector. wire nut and tape?
LOL Ya I suppose that's interior wiring hogie fix.. Ill heat shrink
crewchief... I pulled back the tubing 18" or so. I can only find two black ground wires. There not spliced together. One goes to the brake solenoid the other to the bics. Maybe I'm misunderstanding? Where the new brake solenoid/traction lock solenoid plugs to the harness this is where I pulled back the tubing. Maybe I'm confusing your term mainframe harness side? Oh boy! I want to get this right
I did not peal back the tubing that's on the new solenoid I installed. I pealed it back on the?? Mainframe side??
somewhere in the mainframe harness those grounds should be spliced together. ive never seen one that wasnt. if you cant find the splice, try this, in the mainframe harness , splice in 2 new wires, one for the brake, the other for the BICS coil, and run them back to the battery. clean your battery cables until they are bright and shiney
Those two wires were taped together with electrical tape. But not spliced together. Im wondering if you could give me a call Karl at 734-637-7680 Thank you!!
Im sure the splice you are describing exists. Im obviously opening up the wrong harness
Like crewchief stated, the easiest thing to do is not bother looking for that ground wire splice but rather just run new ground wires from parking brake solenoid and BICS hydraulic lock valve solenoid on main control valve back to the battery ground post. Fairly easy to do.
YES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Problem solved!!!!!!!!!!!!!!You guys are awesome!!!! Thanks a bunch.........Today is my birthday... This is a great present!! OH!? Did I mention YES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
My s185 can't get power to brake lock solonoid, checked fuses, relay all good, what's next ? don't know can anybody help,?. Thank you.
I know this is an old thread but I want to have a manual unlock set up for the brake solenoid. So I need a switch for hold and a push button starter swich for pull? Can I have this with the BICS without screwing up the BICS controller? IE sending power backwards to the BICS when BICS isn't powering the coils?
I read that the BICS system uses low voltage for the hold coils 4-6 volts. I'd really like to get rid of the BICS computer all together and have all solenoids on toggle switches and warning lights for temps and pressures.
Why?
I inherited this low hour Bobcat 864. The rats and mice have been chewing the wires off. I have soldered about 40 wires back together and got it all working. Then I have to leave where it is for a week or two and when I get back it has wiring problems. I have done everything I can think of to stop the rats and mice but I'm not there to fight them. It's 23 years old and the wiring will become more and more of a problem. I'm used to running equipment with two wires. One for the starter and one for the Alternator. That's how all equipment should be built in my opinion. I can power each solenoid with a toggle switch and have a much more reliable and easy to fix machine if I can figure out the hold coil voltage. As for safety - I know the hazards of operating a skid steer and maybe I'll keep the seat bar switch and would never operate it without the bar or get in and out without locking off the the lift and tilt functions. Everything else - temps, oil pressure etc can be on gauges or idiot lights.
Never gutted a Bobcat before, don't know that I'd want to, I'd be building a sheet metal enclosure that the rodents can't penetrate to park it, but that's me. It's possible to make one analog, the Deutz engine only needs a hot wire and a ground for the shutdown coil. Alternator just needs an exciter wire. The only way you can deal with the parking brake solenoid is with a delay timer module for the pull coil circuit, hold coil circuit can be done with an ignition input to a relay. Control valve spool lock solenoids are 12V, can be controlled with either a switch or momentary controlled latching relays, but you're going to loose your seat bar safety feature, again, one of the reasons I wouldn't want to do this. The one thing you won't be able to use is the aux circuit because those coils are not 12V and they work off of a pulse width modulation signal from the main controller. No main controller, no aux circuit.
I use the seat bar already and don't need the computer to enforce it. Those adjustable DC step down units cheap on amazon are PMW aren't they? The bobcat is in a shed so I'm thinking about building a wire enclosure but the door would be difficult to make mouse proof. My dad payed a fortune for this unit and it only has 710 easy hours on it. They ate the whole cab harness off at the hinge point and other areas but I fixed all of that. One rat fell into the fan belt when I started it one day and jammed the belt and melted the idler pulley but I fixed that too. I had it all fixed and went down two days ago and it wouldn't move. I found the ring gear sensor wire eaten through and soldered it back together and that fixed it. But every time I feel like they are going to get a wire I can't see and then I'm going to be screwed. The other thing that is bothers my conscience is that stupid timing belt that is now 23 years old. It doesn't look easy to replace but I better do it..... I would never buy a diesel engine with a timing belt - gears last forever.
The computer doesn't enforce the seat belt on a Bobcat, but what the seat bar does is if you leave the engine running and exit the machine momentarily it automatically locks the parking brake and the loader controls, a worthy safety and possibly required safety feature, you will lose that feature.
I can keep the seat bar switch if it makes everyone here feel safer. I've operated a Bobcat enough to know I don't want to tumble out the front as it goes over!
I said id put a switch on the loader controls for getting in and out or keep the switch on the seat bar because I know about that human mouse trap too! Thanks for pointing it out though because that would be super dangerous!
Everything powered down with the seat bar up should be easy.
One relay operated by the seat bar powering my switch panel and my DC step down power supply - might work.
Keep in mind that seat bar switch is a Hall Effect sensor. If you can figure out how to make that work then you're good, way above my knowledge.
Thanks - I didn't know that. Might have to get a spring pull switch on it or something. Hopefully I don't have to do all this but the mice and rats are terrible there and love wires!
Where is the traction lock on a tracked machine? I tried to find it but couldn't so far.
The silver lining is that I can solder upside down in a cramped space with my glasses falling off and do a beautiful job of it after doing about 40 of them on this machine.