Hello, I'm new to this forum, however I read on here a lot. My 2001 Bobcat 864 has me stumped so I'm posting on here in hopes that someone can help. I have had an intermittent seat bar sensor issue (the traction lock would randomly lock up like I raised the seat bar). I ended up getting a new senor and just taped the magnet in place for the time being. Well the machine ran for about 6 more hours and now I'm back to having my traction lock randomly locking up. Then today I couldn't even get the traction lock to turn off. I had to hit traction lock override and just park it on the job site. I've also had some random other sensors acting up suddenly. The low hydraulic fluid pressure light started coming on and would turn the machine off. So I unplugged that sensor under the cab and it stopped shutting off the machine. I'm 99% sure I don't have a hydraulic pressure issue... Its all electrical. Then today my low oil pressure light started coming on and turning off the machine too. I'm starting to wonder why I'm having so many random electrical issues. I've only owned this machine for about 5 months and have put on a little less than 60 hours. It runs great mechanically but has these electrical issues. Not sure where to start... I've raised the cab and traced wires but nothing looks damaged. Fuses were all good too. Anyone have any ideas or a way to fix the traction Lock?
PS: I'm not even getting the yellow light (Seat Bar Light) on upper panel to light up.
Start inspecting your wiring harness for rubs, cuts any damaged points even if buried in muck inside the frame as sounds like you are losing a ground or sensory inputs may be receiving higher than normal resistance(corrosion/shorts).
Thank you! I looked over the wiring pretty good and didn't find any damage... but there has to be something I'm missing. I'm going down to work on my Bobcat tomorrow and I'll look it over again. Hard part is that this jobsite is about an hour and a half away from home in a remote area. All the wiring under the cab is pretty covered in dirt and I don't have access to water to wash it off.
Does anyone have access to a wire schematic for a Bobcat traction lock system? I was going to buy a manual but not sure that would even be in there. Sometimes the schematics reveal what you need to know
What is traction lock on a skid steer? No idea what a 863 electrical system is like. In general, I'd find, clean, grease, and tighten your grounds near the battery, at the engine and anywhere else you can find them. Maybe add an additional heavy ground wire from the chassis to engine to battery, and smaller ones to any panels that already have a ground wire. Also inspect the panels/printed circuit boards, and clean them with some electrical cleaner if they're dirty.
Good pointers Delmer! I'll bring some electrical grease and electrical cleaner with me tomorrow. As well as some wiring to clean and add grounds.
Traction lock on the skid is a safety system that locks the hydraulics when the seat bar is raised. Some have a sensor on the seat too. In my case the control system thinks I raised my seat bar (when I didn't) I'll be running full speed and bam, the hydraulics lock. Its freaking annoying. Now I can't even get the hydraulics unlocked. I have an enclosure and got stuck inside the machine the other night. Hydraulics wouldn't unlock and my bucket was up. Luckily after messing with it for about 10 minutes, I got the bucket to go down. and to top it off I am getting a low pressure warning that shuts the machine off.
I am starting to wonder if it is the computer. So Friday nothing I did would unlock the traction lock system and the low oil pressure light was coming on and shutting down the machine. I finally gave up and parked the machine. Today I show up to work on it and it runs fine. Traction lock turns off and no oil pressure light. After about 45 minutes to an hour the machine starts acting up again with the same issues. I raised the cab, checked all my wires again. Cleaned some of the connectors, cleaned my relay and fuse connections, swapped the traction lock relay. Nothing I did would unlock the traction lock. I finally gave up and figured maybe I'll try replacing the traction lock sensor again and maybe the pig tail. Other than that I am stumped.
Has to be a breaking or intermittent connection somewhere.
Stopped by Bobcat today and spoke to their service guy. He told me that it sounds like an alternator issue. I also picked up a new hydraulic pressure sender. Got to the job site and fired up the machine. Sure enough the seat bar sensor worked fine but the hydraulic pressure light was on. Flipped up the cab and swapped the sender and the hydraulic pressure light went off. Ran the machine without any issues for about 2-3 hours. Suddenly the seat bar sensor started acting up and a few minutes later the hydraulic pressure light was on again. Battery voltage was at about 12.5 and alternator was strong at 14.5v. (Didn't think it was my alternator because the seat bar light will flicker when the machine is off with the key turned to start). However, I got excited because while probing I wiggled the ground strap from the engine to the frame and it made the seat sensor light click on and off. Thinking I found the problem, I cleaned that ground up real nice.... AND no luck... couldn't get the seat bar sensor to engage and unlock the hydraulics at all. So parked the machine.
My issue is consistent.. Machine runs for around the first hour without any issues. Then the seat bar sensor starts acting up followed by hydraulic and oil pressure sensors. Let it sit for 4 hours and the machine runs fine again. I have 3.4 volts at the seat bar sensor even when acting up. Seat sensor and hydraulic pressure sensors are new. Battery tested good, alternator is good. Cleaned up all grounds and no frayed wires are present. Fuses and relays are good. Cleaned connections. I don't know what else it could be other than the control/computer. Going to see if I can find one to swap in. Either that I might have to take the machine to Bobcat because I'm in middle of an important project and can't get it done with this problem. I'll keep everyone posted once I figure it out.
Something by that explanation is getting seriously HOT, connection, sensor, processor.
Simething may be warming up, expanding, and somehow losing contact or becoming loose enough to cause intermittent no contact. Look at all of the connections close to high heat (like exhaust, if course). Untighten and re-tighten what you can see.
The hard part is that all the electrical exposed to heat appears fine.... Its all back by the alternator and battery. Unless I'm missing something. Couldn't be the alternator because this issue happens with the motor off and key in on position. Plus I have proper voltage. Battery is good. All other electrical isn't near a heat source (Under cab). I've lifted the cab and felt every sensor/connector and none are putting off heat. The electrical system isn't very complicated. Just frustrating.
you might be on the right track with the ground wiggling making the sensor click on and off. Or maybe not? I'd dig into that more, take a volt reading of both sides of the ground cable with the engine running, all accessories on. Or run extra grounds everywhere. The cable itself can have breaks in it. Also, are those volt readings with the engine off at the battery, and with the engine on at the battery? stupid question, but have to ask, sorry. You might also have two problems, a weak board, and a loose ground or other connector. If you can see the control board, sometimes you can SEE the bad component, like a smoked doohicky or a bulging capacitor (black barrel component), or hear a relay click on and off when you tap it but it shouldn't otherwise click.
The battery ran 12.5 volts on a bench test. But it was getting around 12.7ish with the motor running. 14.5 ish at the alternator with the motor running. I tried cleaning all the grounds I could find... un-screwed them and polished the metal up. When my sensors started acting up, I tried adding a ground to the seat bar sensor. It didn't do anything. But I touched the power wire and ground on the seat sensor wire. When I took the wires apart the seat sensor/traction look button clicked on and then went off.. Did it again and the same thing happened. Not sure why it would do that. Almost like it tricked the sensor or computer and made it work for a second. Good idea at taking a peak at the control board... Maybe I will see a burn mark or something. I'll have to unplug all the harnesses and pull it off. More and more things are pointing to that control board. I found a used one around $500 but I hate to throw parts at it.
sounds like you have a voltage loss between the alternator output and the battery. should be only about 1/2 volt max drop. you may have voltage fluctuations to the electronic components. check the voltage drop with the eng shut off . the voltage should be the same at the batt and alternator output terminal hot or cold
Could be a broken wire inside the wire’s insulation that you can’t see. Maybe start with the main alternator and battery wires thst get the most heavy use and heat.
That's not right, fix that before you worry about anything else. Use the voltmeter to figure out where those 2 volts are going.
Another point noted above that more or less goes with that intermittent disconnect of harness clicking, start looking for a inline diode in that harness, if one has failed could be getting feedback causing this entire issue. Try to get a schematic on the system, anything looking like ->I- (sorry for the bad illustration) in the wire lines is a diode. Can be across a plug connector, inline to a wire which will appear as a rubber covered splice or connector, even on a circuit card, a popped one will be burnt or browned. Corrosion at a diode can do the same thing on a card.
Are you sure I should have 14 at the battery? The tech at Bobcat told me I should have around 14V at the alternator. I just figured 12ish at the battery was normal. Sure enough... Went down to drop off my mini ex and pick up the Bobcat today (Decided to just take it to Bobcat because I'm loosing too much time troubleshooting this thing).... Dang sensors were acting up right off the bat. Couldn't get it on the trailer with the hydraulics locked.
Probably won't help, but, when I had 863 & 864 Bobcats, I had issues with the seat sensors, not the seat bar. Had issues with the seat sensor on all five of mine. As for the voltage, it had damned well better be the same voltage at the alternator as it is at the battery.
With the alternator pushing hard on a borderline battery the voltage is not stable enough for the controls within the processor. As little as two or three volts or excess amps will drive a machine nuts. Happens trucks cars HE do not care for odd power fluctuations especially of resistance in a cable is intermittent sending spikes will just expand on the problem.
yes, we're sure. If you're losing 2 volts to the battery something is seriously wrong with a wire or connection somewhere. And it should be easy to find with a voltmeter. normally there might be half a volt drop from the alternator to the battery WITH all the accessories running, nothing with the battery charged and not much running, you have found a problem, maybe THE problem.
Okay... I ran my test probe off the starter wire and negative battery terminal (Its really hard to reach the positive wire on the battery). I'm getting same voltage at the starter and alternator while running. I apologize for spinning everyone in the wrong direction. Not sure why I thought I had less voltage at the battery. However, I went down yesterday and all my electrical was going haywire off the bat. Couldn't get the tractor to run. Today I show up and the machine ran perfect all day. First time in weeks its ran like that. No issues and ran like 4+ hours. I didn't shut it off once I realized it was going to work. Really strange.
my crystal ball is still glowing electrical, if not the alternator wire, then possibly a ground. It gets tougher when it works sometimes and doesn't work sometimes. You have to diagnose it while it's not working, if the wire decides to connect and run then you have nothing to find.
Thanks Delmer. I was shocked today to get a full day of work in. I planned to trouble shoot the machine. Jumped in and it ran all day. Electrical issues are frustrating.
Resolved! It was the computer. After going through every wire and sensor I could find, I found a cheap used one for sale and decided to buy it. Sure enough it fixed my issues.
Had it gotten contaminated or wet?
I have only owned the machine since June 2017. Since I've owned it, the computer has never been contaminated. Visually, it didn't look like anything happened to it. I spent more money replacing sensors than buying the computer. Just glads its fixed.
Resolved! It was the computer. After going through every wire and sensor I could find, I found a cheap used one for sale and decided to buy it. Sure enough it fixed my issues Hey I know this is and old post but I am have the EXACT same issue did you replace the upper left controller in the cab or what computer did you replace? I appreciate any help.
Hi Holden - did you resolve the issue? I'm tempted to put a switch on every solenoid and get rid of the whole BICS system.