751 Will not move and no controls

[dmk1978]

I have a 1999 Bobcat 751 and about a week ago the engine light came on and we lost the ability to move the machine or operate the bucket. We unplugged a few of the relays in by the engine for the start and power and the problem went away. I think this may have been just luck because today the engine light came on and the machine is doing the same thing. I tried to switch around the relays, I made sure they are not corroded but with no luck. I checked the hydraulic fluid and it is full. I am lost any ideas.....greatly appreciated I am really frustrated.

 

[RonAus]

I do not know how the 751 compares to a 753 or 763 but check the fuses and the fuse holders, you might have some corrosion there. It sounds like the bics.

 

[maccor]

I do not know how the 751 compares to a 753 or 763 but check the fuses and the fuse holders, you might have some corrosion there. It sounds like the bics.

Sounds silly, but is there a good connection to ground on the battery? My 751 "stopped" working twice now and it was a crappy ground connection (now fixed). But BICS does sound like a good place to start. Or the interlock solenoid...might be a intermittent connection to it.

 

[dmk1978]

Sounds silly, but is there a good connection to ground on the battery? My 751 "stopped" working twice now and it was a crappy ground connection (now fixed). But BICS does sound like a good place to start. Or the interlock solenoid...might be a intermittent connection to it.

How did you fix the ground issue? Where do I start with the BICS? Would you be able to describe where I locate the interlock solenoid? Thanks for your help....

 

[Tazza]

How did you fix the ground issue? Where do I start with the BICS? Would you be able to describe where I locate the interlock solenoid? Thanks for your help....

As Ron mentioned, start with the fuse holders, i had this problem with a 751 i owned that the fuse holder for the main power was corroded. It would work some times and others it flat our refused to work. Replaced it with an inline fuse holder and it was fine ever since.
As for grounds, check the connection at every point you see a ground lug on the wiring harness. You need a good connection between it and the frame.

 

[maccor]

How did you fix the ground issue? Where do I start with the BICS? Would you be able to describe where I locate the interlock solenoid? Thanks for your help....

Start at negative side of battery and follow it to wherever it is connected...usually a bolt through to the chassis/frame. Regarding BICS....when the problem occurs (or if machine is currently not working), look at the lights on the BICS. Are they all green? If not, need to look into what might be wrong. Interlock solenoid...Raise cab, should be gold-ish colored cylinder in middle of compartment, 1" diameter by 3" tall. Wires coming out of it... the color orange comes to mind. You might go online and find an electronic copy of the repair manual. Cost me $10-$15 but it was worth it trying to figure things out. I wouldn't say it is the most comprehensive manual, but should help. Mike

 

[dmk1978]

Start at negative side of battery and follow it to wherever it is connected...usually a bolt through to the chassis/frame. Regarding BICS....when the problem occurs (or if machine is currently not working), look at the lights on the BICS. Are they all green? If not, need to look into what might be wrong. Interlock solenoid...Raise cab, should be gold-ish colored cylinder in middle of compartment, 1" diameter by 3" tall. Wires coming out of it... the color orange comes to mind. You might go online and find an electronic copy of the repair manual. Cost me $10-$15 but it was worth it trying to figure things out. I wouldn't say it is the most comprehensive manual, but should help. Mike

I replaced the negative side of the battery terminals, I then cleaned the ground going to the starter. I cleaned up the grounds on the chasis and under the cab. I checked all the connections under the cab along for corrosion but everthing there is good. Any way I could get a picture of the interlock solenoid. I will have a manual in a few days but I wanted to keep working on the problem until that time. How do you test the solenoid once I locate it?

 

[maccor]

I replaced the negative side of the battery terminals, I then cleaned the ground going to the starter. I cleaned up the grounds on the chasis and under the cab. I checked all the connections under the cab along for corrosion but everthing there is good. Any way I could get a picture of the interlock solenoid. I will have a manual in a few days but I wanted to keep working on the problem until that time. How do you test the solenoid once I locate it?

This is from a different forum, but the thread had quite a good bit of information on the traction lock solenoid. http://www.heavyequipmentforums.com/showthread.php?5117-Bobcat-753-Traction-lock-problem Here is an image of the BICS error codes that would appear on your unit based on what might be wrong.... http://media.photobucket.com/image/...t/BICS_Troubleshooting_Chart.jpg?t=1312479844 Might help keep you going until the manual gets there....I bought a PDF version and had it in less than a minute.... Mike