763 bobcat electrical problem

[WildWIGinseng]

I have a 763 bobcat g series problem. Dump hydraulics locked up and parking brake locking up. Codes said alternator so I replaced it and put a new battery in. Replaced fuses and made sure I was getting power to them. Still the same but getting worse, the machine will shut itself down completely after running a few minutes. Temp gauge going haywire too. The best luck I've had is to have the seat bar down before starting and I can get a minute or two of run time before the brake locks up. Any ideas on where to go from here?
Thanks

 

[willie59]

What codes are you getting when the alarm goes off?

 

[WildWIGinseng]

First it's a 753 not a 763. I'm getting a 3-09, 9-21,18-07 and 41-09. The fuel gauge does not work and I know one of those codes is for that. It has never worked so I ruled that out as a problem.

 

[WildWIGinseng]

Also I'm getting the exclamation point light and the battery light on the dash.
Thanks

 

[willie59]

I don't have an answer for your problem as you have a lot going on there. You've replaced the alternator and the battery, but have you actually checked the voltage at the battery with it running? Have you cleaned all the terminals well? What about the ground wire connections at the negative terminal at the battery, have you busted that loose and cleaned them well? Lastly, have you checked voltage at the master fuse with it running?

 

[WildWIGinseng]

I did all the battery terminal and connections, I do not have a voltage meter so maybe I should pick one up and try testing that. Is there any way that this could be caused from the arm bar sensor? As I said if I start it up with the arm bar up I immediately get the lights and lock ups but if I have it down, start it and hit the green button I can get a couple of minutes out of it before it starts acting up.
Thanks

 

[willie59]

I can't say anything isn't possible, but the lap bar sensor has its own fault codes and they aren't showing up. With the G series Bobcat, pretty much everything electrical is controlled by the main controller, that's where all your codes are coming from, things that the main controller is seeing in the system. None of those codes are related to the lap bar, rather, voltage problems. If you've checked all those issues and found they're not faulty, then it's possible the main controlled is flipped out. It does happen. But after you've done everything to make sure all these noted issues are good, and before you condemn the main controller, it would be worth it to have a Bobcat tech plug into the machine and verify.

 

[WildWIGinseng]

Yea, I'm just about there, taking it to the dealer, was just trying to avoid that big bill. Where is the computer on this machine and is it something I can replace or does that have to be done by a dealer.
Thanks

 

[Delmer]

dude, a volt meter is $3 at harbor frate, and worth it. Check the voltages at the battery, running at the battery, between the engine and battery etc. etc. until you're confident everything in the system is seeing correct voltage.

Cables can rot out in the middle of the run, connectors can be rotten inside, anything can happen with enough corrosion.

 

[WildWIGinseng]

Ok, I'll try that and let you know what I find.
Thanks

 

[willie59]

dude, a volt meter is $3 at harbor frate, and worth it. Check the voltages at the battery, running at the battery, between the engine and battery etc. etc. until you're confident everything in the system is seeing correct voltage.

Cables can rot out in the middle of the run, connectors can be rotten inside, anything can happen with enough corrosion.

Yep, that's why I said "check the voltage at the master fuse with it running". The master fuse comes right off the positive battery terminal, but a poor connection inside the cable connection to the terminal can cause all sorts of flip out on a G series main controller.

 

[frg]

chekc the fuse, the is a 25A fuse named Alt/Kit. i think it is blowen.

 

[WildWIGinseng]

I checked the alternator fuse, it was not blown, replaced it for good measure and made sure I had power there. All my volt checks are good. Again if I have the seat bar down and start it I can get it to run fine for a while. Once I put the seat bar up everything goes haywire, or if I start it with the bar up I have warning lights on and will not be able to get the parking brake unlocked.

 

[Delmer]

Like Willie says, you can get a bobcat tech out to check the controller, I don't have anything to add to check the controller.

The only other thing I'd still check is the voltage at the controller, and maybe at the switch at the lap bar. Check the voltage they're seeing, that is the power and ground at the controller, and at the switch. Since you can get it to work consistently and get it to fail predictably, it might be possible to find what's going on.

Sometimes a failing coil will work for a bit cold but fail as soon as it heats up, is there a solenoid that's getting power as it's supposed to but failing to act when it gets hot? If it was partly shorted inside the coil, it would draw more amps and possibly cause a low voltage somewhere it the circuit. Could easily be a smaller relay coil inside your controller too.

 

[WildWIGinseng]

What do you mean specifically when you say "the controller" not sure I'm following you. The coil thing would make sense since wants it is warmed up usually everything goes nuts. Thanks for being patient with me, I know my way around a wrench but the computer/electronics sometimes has me baffled.

 

[Ronsii]

Controller == computer. computers do not like voltage fluctuations or spikes!!! they need a very good connection to the battery and the ground side of the battery, any time you start seeing weird things happen the first thing to check is that the computer is getting good solid voltage!!! this includes checking fuses that may be feeding the computer grounds to it and a few other things... also check along the entire wiring harness as rodents like to chew through things and cause shorts or just movement and vibrations can rub through the wires insulation and cause similar issues.

Computers can warm up and have problems also kinda like a coil would do just on a more electronic level but still heat related when a component in the computer is going bad.

 

[WildWIGinseng]

Ok thanks for the explanation. Where exactly is the computer on a 753, G series? I did check all wiring for rodent chews etc and did not find anything.
Thanks

 

[willie59]

It's "Bobcat" who refers to the computer (ECU) as the "main controller", it's their terminology. On a G series, sitting in the seat, it's located behind those sheet metal panels to the left of your left foot.

 

[WildWIGinseng]

Ok, thank you!