863 blown "computer" fuse

[Smack]

The first clue was that I turned the key and got no lights, no anything. I thought that the battery was getting old and weak, so had it checked, desk clerk said it was defective, and installed a new battery. Surprise, still got no response when I turned the key. I opened the fuse cover and found a blown fuse labeled "computer". Replaced that fuse and it immediately blew again. My problem solving: disconnected starter, fuse blew again. Disconnected alternator, new fuse blew again. Disconnected fuel shut-off solenoid, new fuse blew again. Disconnected the BICS, starter module and center ('parking brake'?) module, new fuse blew again. Started looking at harness, but did not find an obvious short to the chassis. The fuse block is a bit rusty; I've cleaned it and don't see anything shorting right at the fuse. Got the maintenance manual, but I don't see all of the wiring (in schematics) that I see in the Bobcat. Where does that AWG4 wire (with 100A fuse) go??? I took the new battery back out, but didn't see any issues caused by the installation. Anyone seen this particular problem? Suggestions? Why doesn't my Bobcat electrical schematic show the BICS circuits? Thanks for any help. Brian

 

[7LBSSMALLIE]

you probally got a 7 14 pin connector on lh ldr frame? probally got smashed. dissiconnect 14 pin harness (cannon plug above batt lft side) replace fuse)

 

[bobbie-g]

you probally got a 7 14 pin connector on lh ldr frame? probally got smashed. dissiconnect 14 pin harness (cannon plug above batt lft side) replace fuse)

Thinking way back, I had a similar problem on a T180. It had the aux elec connector up by the aux hydraulic connectors on the lift arms, left side. Prev owner had replaced the real connector with a 4 pin trailer connector, and wired it so the exposed terminal was 12v. Wow. It would intermittently contact the loader arm and blow a fuse. I never suspected the dude had done such a poor job of wiring it wrong. I think that connector/harness is the one 7lbssmallie is referring to, which can be disconnected at a 14 pin connector near the battery. Good luck, and give us feedback so others can benefit! --- Bobbie-G

 

[Smack]

Thinking way back, I had a similar problem on a T180. It had the aux elec connector up by the aux hydraulic connectors on the lift arms, left side. Prev owner had replaced the real connector with a 4 pin trailer connector, and wired it so the exposed terminal was 12v. Wow. It would intermittently contact the loader arm and blow a fuse. I never suspected the dude had done such a poor job of wiring it wrong. I think that connector/harness is the one 7lbssmallie is referring to, which can be disconnected at a 14 pin connector near the battery. Good luck, and give us feedback so others can benefit! --- Bobbie-G

Thanks for the suggestions. I do have the 14-pin connector just above the battery, but it is 'plugged' (I don't have the aux harness) and appears fine (not smashed). Does anyone know where that 4AWG cable runs (runs into a harness forward of the battery)? The computer fuse has a red wire (assuming hot, direct from battery) and 3 red/white stripe wires on the other fuse lug. I'm thinking of tracing those 3 wires and doing a continuity/grounding test next. Still have not found a schematic of the BICS. Thanks again. Brian

 

[Smack]

Thanks for the suggestions. I do have the 14-pin connector just above the battery, but it is 'plugged' (I don't have the aux harness) and appears fine (not smashed). Does anyone know where that 4AWG cable runs (runs into a harness forward of the battery)? The computer fuse has a red wire (assuming hot, direct from battery) and 3 red/white stripe wires on the other fuse lug. I'm thinking of tracing those 3 wires and doing a continuity/grounding test next. Still have not found a schematic of the BICS. Thanks again. Brian

Update. Continuity test between one leg (there are three red/white stripes wires) of the "computer" fuse shows that side is grounded. I unplugged the connector from the controller (Bobcat P/N 6682421) and the red/white striped wires are no longer grounding. So, I think that something in this black box has faulted to ground. It looks expensive... and I'm guessing this is a dealer only type of part. Can the dealer test the controller to determine if it is faulty ? I will upload a photo, if I figure out how. Brian

 

[Tazza]

Update. Continuity test between one leg (there are three red/white stripes wires) of the "computer" fuse shows that side is grounded. I unplugged the connector from the controller (Bobcat P/N 6682421) and the red/white striped wires are no longer grounding. So, I think that something in this black box has faulted to ground. It looks expensive... and I'm guessing this is a dealer only type of part. Can the dealer test the controller to determine if it is faulty ? I will upload a photo, if I figure out how. Brian

I don't believe they can test the controller, but they can install another controller to see if the problem still exists or not.
You can use a used controller, but may need to talk to your dealer to get it programmed to enable all your functions, but i am unsure if you can alter the program like that on a used module.
Sadly it does sound like it's an internal short.

 

[Smack]

I don't believe they can test the controller, but they can install another controller to see if the problem still exists or not.
You can use a used controller, but may need to talk to your dealer to get it programmed to enable all your functions, but i am unsure if you can alter the program like that on a used module.
Sadly it does sound like it's an internal short.

I took the 863 in to Bobcat Austin last week. They confirmed it was an internally-shorted computer ("controller"). New computer $1200. Had them change the timing belt, too $1100 (7.5 hrs labor?). New problem: the toggle on the right-hand Steering Lever (Deluxe handles) does not operate the auger (front hydraulics). The toggle (operator's side of the handle) does nothing (it used to work), but the 'trigger' (front side of handle) will rotate the auger backwards. Here is the new question: since the trigger does something, does that mean the handle's wiring/connection is good and the problem is that the dealer did not program the front hydraulics operation or the Deluxe handle operation? Brian

 

[Tazza]

I took the 863 in to Bobcat Austin last week. They confirmed it was an internally-shorted computer ("controller"). New computer $1200. Had them change the timing belt, too $1100 (7.5 hrs labor?). New problem: the toggle on the right-hand Steering Lever (Deluxe handles) does not operate the auger (front hydraulics). The toggle (operator's side of the handle) does nothing (it used to work), but the 'trigger' (front side of handle) will rotate the auger backwards. Here is the new question: since the trigger does something, does that mean the handle's wiring/connection is good and the problem is that the dealer did not program the front hydraulics operation or the Deluxe handle operation? Brian

Sadly if it's a deutz engine, it does take time to do the belt. I have never done one, but it is quite involved, i'd think the dealer would know all the tricks to do it quickly.
If the trigger works, i'd like to think the computer was programmed correctly, was it working before the computer died and got replaced? If it did, you may need to talk to the dealer to see if they could have forgotten something.

 

[Smack]

Sadly if it's a deutz engine, it does take time to do the belt. I have never done one, but it is quite involved, i'd think the dealer would know all the tricks to do it quickly.
If the trigger works, i'd like to think the computer was programmed correctly, was it working before the computer died and got replaced? If it did, you may need to talk to the dealer to see if they could have forgotten something.

Thanks Tazza, I'll call and ask if the computer needs a specific programming input that was forgotten. Alternatively, do any of those relays in the fuse block control the delux handles? I'm not sure why the trigger would work and the thumb toggle would not though. I'll scan the schematics to see if I can figure out a link... Brian

 

[Tazza]

Thanks Tazza, I'll call and ask if the computer needs a specific programming input that was forgotten. Alternatively, do any of those relays in the fuse block control the delux handles? I'm not sure why the trigger would work and the thumb toggle would not though. I'll scan the schematics to see if I can figure out a link... Brian

I'm really not sure if the handles will be fused, i thought they went straight to the controller, they will only run low foltage and current, or so i thought.

 

[Smack]

I'm really not sure if the handles will be fused, i thought they went straight to the controller, they will only run low foltage and current, or so i thought.

So, the handle wiring was just fine. The service manager told me that these "older machines" have to have the front hydraulics activated in the software and this was not done on my machine when they replaced the controller (computer). He drove out to my house one evening, opened the door in the back and connected to plug (I thought it was for an unused option) just above the battery. His laptop had the controller software and, sure enough, there was a box for Front Hydraulics and that box was not checked. The whole correction to about 3 minutes. I started the machine and viola, the front hydraulics were working ! I had an auger attached and ran it CW and CCW to confirm hydraulic operation. Back to normal !! Brian

 

[Tazza]

So, the handle wiring was just fine. The service manager told me that these "older machines" have to have the front hydraulics activated in the software and this was not done on my machine when they replaced the controller (computer). He drove out to my house one evening, opened the door in the back and connected to plug (I thought it was for an unused option) just above the battery. His laptop had the controller software and, sure enough, there was a box for Front Hydraulics and that box was not checked. The whole correction to about 3 minutes. I started the machine and viola, the front hydraulics were working ! I had an auger attached and ran it CW and CCW to confirm hydraulic operation. Back to normal !! Brian

Glad it was so simple!
It baffles me as to why the front aux hydraulics is not enabled as standard, but i'm sure there are reasons.

 

[Stonehands]

Sadly if it's a deutz engine, it does take time to do the belt. I have never done one, but it is quite involved, i'd think the dealer would know all the tricks to do it quickly.
If the trigger works, i'd like to think the computer was programmed correctly, was it working before the computer died and got replaced? If it did, you may need to talk to the dealer to see if they could have forgotten something.

Hello Tazza I have an 863 F series Turbo unit. I hear the horror stories on what happens when a timing belt goes out. Is changing this on my Deutz powered 863 a do it your self process or best left to the Bobcat shop? I am not unhandy and do all the routine repair and service on all of my equipment but I know getting to anything in the back of this Bobcat looks like a job. I have replaced the injectors and hoses, alternator and starter myself and had no issues. Your thoughts? do it yourself or send it out.

 

[Tazza]

Hello Tazza I have an 863 F series Turbo unit. I hear the horror stories on what happens when a timing belt goes out. Is changing this on my Deutz powered 863 a do it your self process or best left to the Bobcat shop? I am not unhandy and do all the routine repair and service on all of my equipment but I know getting to anything in the back of this Bobcat looks like a job. I have replaced the injectors and hoses, alternator and starter myself and had no issues. Your thoughts? do it yourself or send it out.

You will need special tools to do it, i have heard of other members talking to their deutz dealer and hired the tools to do the job. They did it without any problems, i'd assume the belt/idler kit would have instructions.
If you are handy with a spanner, i can't see why you couldn't do it.
Just mark everything before you take the belt off, mark the gear teeth and the belt, just to be sure if something goes wrong and you aren't sure what marks are to line up where, you will have it.
It's a job i have never done myself, but i have done it on other engines without any issues.
You could always ask the dealer how much, but sadly i bet it won't be pretty as it does take time.