BICS

[Stephend]

I have a 1999, 751 diesel with about 1750 hours on it. I am using it with tree shear to clear cedars on my small ranch in Oklahoma. This is my problem: I have owned the unit for about 3 years and have used it for about 2 years before I started having this problem. About 2 months ago I going to cut cedars when it suddenly just quit. I had replaced the fuel pick up tube about 3 months ago. After it quit it would not even click when I turned the ignition. I made several bad assumptions; I cleaned all the contacts, I checked the starter, the ignition switch, the battery everything. Then my wife said did you check the fuses? Sure enough when I checked the fuses the BICS fuse was blown. The diagram shows a 15 amp but it had a 25 in it. I replaced it with a 15 amp which lasted about 6 weeks then it started to blown fuses again. I could not keep a 15 amp it as it blow as soon as turned the ignition switch, so I moved to a 20 amp that helped a little but still would blown after about 20 minutes of operation. I had to go back to a 25 amp. Does anyone had any ideal what could be blowing the fuse? Can I keep use the 25 amp without doing any damage? Thanks in advance for your help.

 

[OldMachinist]

Anytime a fuse blows there is something wrong and putting in a higher amp fuse could cause more damage or fire. Try to figure out which wire supplies power to the BICS controller and check its entire length for rubbed thru areas that may be shorting out. If you don't have a wiring diagram start at the fuse block and see which wire is on the fused side. Most of the wires are 16ga and a 25 amp draw should be melting the insulation so it shouldn't be too hard to find the short. Good Luck

 

[mrfixitpaul]

Anytime a fuse blows there is something wrong and putting in a higher amp fuse could cause more damage or fire. Try to figure out which wire supplies power to the BICS controller and check its entire length for rubbed thru areas that may be shorting out. If you don't have a wiring diagram start at the fuse block and see which wire is on the fused side. Most of the wires are 16ga and a 25 amp draw should be melting the insulation so it shouldn't be too hard to find the short. Good Luck

If it wouldn't even start with the fuse blown, the fuse can't be for the BICS. The BICS is the safety interlock system, only prevents brake and hydraulics from unlocking, not able to shut down the engine. Maybe the fuse panel is installed upside down or something. Anyways, OM is right by saying trace the wires from the fuse to look for the short. If cab has windows, check where the back corner of the window hits the wiring harness.

 

[Stephend]

If it wouldn't even start with the fuse blown, the fuse can't be for the BICS. The BICS is the safety interlock system, only prevents brake and hydraulics from unlocking, not able to shut down the engine. Maybe the fuse panel is installed upside down or something. Anyways, OM is right by saying trace the wires from the fuse to look for the short. If cab has windows, check where the back corner of the window hits the wiring harness.

Armed with the new information from the 2 replies I checked out my fuse diagram and to my dismay determined that I had miss read the labels all this time. I it was not my BICS fuse that was blowing it was the engine fuse. It turns out the BICS fuse is a 10 amp and the engine fuse is a 15 amp. Now that I have gotten some of the the egg of my face( my says that is normal for me to wear egg on my face!) what do I need to look for or at that would cause the engine fuse blow. I guess in away I am asking just what is in the engine circuit that could blow a fuse besides a wire rubbing some where. Find a rubbed wire is going to be challenge since most of the wire are wrapped in plastic bundle. Again thanks very for past and in advance for future help.

 

[OldMachinist]

Armed with the new information from the 2 replies I checked out my fuse diagram and to my dismay determined that I had miss read the labels all this time. I it was not my BICS fuse that was blowing it was the engine fuse. It turns out the BICS fuse is a 10 amp and the engine fuse is a 15 amp. Now that I have gotten some of the the egg of my face( my says that is normal for me to wear egg on my face!) what do I need to look for or at that would cause the engine fuse blow. I guess in away I am asking just what is in the engine circuit that could blow a fuse besides a wire rubbing some where. Find a rubbed wire is going to be challenge since most of the wire are wrapped in plastic bundle. Again thanks very for past and in advance for future help.

The power from the engine fuse goes to the ignition switch and then is distributed to several places when the key is turned. Here's what I would do since you said the proper size fuse blowns right away when you turn the key. Pull the ignition switch, figure out which wire brings the power to the switch and which one is for the starter relay. The remaining wire or wires are the ones your looking for. Disconnect them leaveing one on at a time and put in the proper size fuse, turn the key and check the fuse. If it didn't blow turn the key off and do the same thing with each wire until you blow the fuse. Now you know which circuit is drawing a high load, trace it and disconnect it from the other end, put in a new fuse and turn the key if it blows the wire is shorted to ground somewhere, if it didn't blow what ever it was hooked to is the problem. If the wire is shorted you can run a new one of the same size next to the wire bundle and leave the old disconnected at both ends. If whatever it was hooked to is the problem then come on back and ask about it.

 

[Stephend]

The power from the engine fuse goes to the ignition switch and then is distributed to several places when the key is turned. Here's what I would do since you said the proper size fuse blowns right away when you turn the key. Pull the ignition switch, figure out which wire brings the power to the switch and which one is for the starter relay. The remaining wire or wires are the ones your looking for. Disconnect them leaveing one on at a time and put in the proper size fuse, turn the key and check the fuse. If it didn't blow turn the key off and do the same thing with each wire until you blow the fuse. Now you know which circuit is drawing a high load, trace it and disconnect it from the other end, put in a new fuse and turn the key if it blows the wire is shorted to ground somewhere, if it didn't blow what ever it was hooked to is the problem. If the wire is shorted you can run a new one of the same size next to the wire bundle and leave the old disconnected at both ends. If whatever it was hooked to is the problem then come on back and ask about it.

Just wanted to say thank you. this past weekend I had the time to look for a short. I started by just looking for wires that might be rubbed to expose bare wire. I wrapped those with electrical tape even if I could not see bare wire and tied them back with electrical ties and that solved the problem. It ran it for a total of about 8 hours without one blown fuse. I also noticed it did not bog down as well, I guess from time to time I was getting a quick short causing the electric shut off to momentarily to close causing it to bog down. In summary all is well. Thank you!