Hello! Thanks for this greate forum! At first,sorry for my bad english-grammar. I have some problems with my bobcat 751.(2100 hours) The engine is 4 syl peugot diesel XUD. Last autumn i washed the bobcat, and stored it in a garage during the winter. Yesterday i started the engine. The engine is running well. But i can not move it! Could not get the brakes off, the hydraulic is not working either. I can drive forward and backwards 3inches.But stops in the brakes. When i turn on ignition, or start engine, and even when "operator in seat" "seat bar down" all the BICS indicatorlights is always OFF. All fuses next to the engine is tested and they are ok.
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mrfixitpaul
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if none of the bics lights are on, including the power light, recheck the fuses as they can corrode and look good but not work. next check/swap out the 'switch power'relay.
the fuses are rechecked again. Used a test lamp first,then a multimeter with ohm on the fuses. They were fine. Tried also to change "brake relay vs switch relay" . Both seems to be working fine. Then i disconnected the BICS control unit inside the driver cabin. I found 1 wire with power. I opened the BICS unit,and checked inside. The printcard ,diodes; everything looks good. No corroson or water have entered inside the bics unit. So no im not sure what to do.
mrfixitpaul
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If you are getting power my next guess would be to check the grounds.
If the BICS box light is out, its a wiring or BICS bix issue, it controls the brake and hydraulic lockout system. I assume you have checked the main connections in the harness? the big round plug/socket? if you look in the manual section, OM has the manual i sent him for a 751, there is an electrical wiring diagram. I used that exact scan to work out burnt wiring on my 751. It will tell you where 12v should be in the wiring loom to the BICS box. I'd start there.
All of the bics light is out. Checked all the connection i could find. Can somebody share the wiring diagram on this site?
OldMachinist
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Check the fuses in the engine bay too, they get corrosion on the legs and may not be providing power to the bics box.
thanks! i called the bobcatdealer and discussed the problem with them. they told me that if the BICS box got one + wire, and one - wire,and it wasn't working,then i had to buy a new BICS box. is this correct? i hope not..... because it costs 1.291,24 USD Im afraid this part is not available on the pirat-market, so i have to buy an orginal one.
OldMachinist
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Yes if you have ground and power on the proper wires and the BICS power light isn't coming on the box is bad or the connection at the box has corroded terminals not making connection.
A BICS box is not programmed, you can get one from a bobcat wrecker if you can find one. Its an alternative to buying a new one from the dealer.
If power is going in, i'd have to agree, the box may be bad or a terminal. Power is 'generally' the orange one. Check the wiring diagran OM gave you a link to. I used that one to rewire my 751, take your time, print it out and stick it together (multiple pages) and work out wire colours from the plugs. Its not as hard as it may seem. There are lots of wires, but go slow, and take notes. All the wires are colour coded, it helps a LOT.
At the wiring hardness connection to the bics box, there is a lot of numbers. 1 - 32 I used a multimeter. Ignition ON. Number 8 is the only wire with + power. Ignition OFF. I ohmed all the wires, from battery minus, to each pin in the contact. Number 1.2.3.4.5.8.16 is in contact to minus. Is it not strange that numer 8 is both + and minus? Probably a switch that is grounded. I dont have a printer or pc in the garage, i have to borrow a printer and print the wiring diagram soon. Is it possible to easyli swap out the whole bics box? Will the machine work without it?
The box is 3 or 4 bolts, slip it out, pull the plug and plug in another box. Its that simple.
What colour was the wire? that is used to identify what is the main power from the ignition too. Orange or orange with a green stripe? i can't remember exactly.
See if you can swipe a printer, the wiring diagram will make it much easier!
This weekend i got the wiringdiagram written on paper. + 12v(orange) and -ground(black) is good. So the problem have to be at the bics controller box. I have called a lot of possible" bobcat wreckers" in norway, but nobody got 751 parts. So if you know anybody in the USA who is selling 751 in pieces,give me a tip.
Don't worry about it being a 751, the BICS box is the same in 751, 753, 763. This is for the BICS machines, not the BOSS.
I have a 763, the BICS box in it is the same as the 751 i had.
mrfixitpaul
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Also same as 773, 853. The 863 & 873 are definitely different and won't work for you because they have an rpm sensor to lock the brake if engine stalls.
Hi, I have been reading this thread with interest I have a 751 and untill the other day all,was fine, powered off and went to restart no power no lights no click of the relays not even the relay to relase hydraulic pressure would I be correct in assuming this may the the power switch relay causing this; or at least is it a good place to start? cheers Andy
The switch is one place, the battery is another. Batteries these days can simply go dead for no reason. Check the voltage and keep checking it when the key is on. Some may show power, but when there is a slight load it drops to zero.
If it has a main power fuse (about 200A), look there as well. Mine didn't have a fuse, but newer ones do.
Thanks for the info, I didn't know about the main fuse any idea where it might be located? If not I'll just follow the +ve from the battery. Thanks again I'll give you an update later. Cheers
