My 753G (1,700 hours) is completely dead. No lights, no indication there is any battery at all, but the battery reads 12+ volts. Last time running, the fuel / temp lights would flash several times with the ignition key removed, as if the key was turned on and off to the first (ignition) switch position. With the plug removed from the BICS panel I've got 12+ volts at the battery terminal of the starter switch - when the BICS panel is plugged in it falls to around 2v. There is continuity between all the pins of the 10-pin BICS & starter panel plugs with the exception of the ignition pin. I've inspected the wiring harness from the two panels (BICS & starter) to the back post of the cab and all looks good there. I can jump the solenoid and the engine turns over normally. I've inspected the main electrical plug above the battery and all the pins look very clean. The battery terminals have been cleaned. Continuity across the ignition switch positions appears normal. I'm thinking either the BICS or starter circuit boards are bad (there are no obvious burnt spots), and am looking for how to test them. Based on some other postings here, I see that Bobcats have an electric panel behind the seat? I haven't looked at that and since I'm 3 hours away from my machine I won't be able to until the weekend. I've ordered a repair manual from Finney but would greatly appreciate any tips if anyone has wrestled with an issue like this before. Thanks, Bruce
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But if the battery had a bad cell the engine wouldn't turnover normally when I jumped the solenoid, no?
I didn't read your post too well, early badger game equals early drinking. Honestly if I was checking this out, i'd swap the controller.:
The controller? Do you mean the BCIS circuit board? I'd like to test it before replacing. Does anyone know how to test whether one of the circuit boards is bad? (I hope that's covered in my yet-to-arrive service manual.)
When you say BICS board, are you talking about the left dash. Most likely the dash is not you problem. First, check all the fuses. All the fuses are between your legs in the the cab. If all fuses look good, flip the cab and check the wiring going to the cab down to where it meets the mainframe harness. The contoller should be located on the leftside of the machine under the cab. More then likely yours is the four connector style. There is no good way to test other then swap.
Dan, yes, I was talking about the left dash.
I haven't checked the fuses but will next weekend when I'm up with the machine (for the four years I've owned it, I've only had to change oil, filters and grease, so now I'm just getting familiar with the rest).
"flip the cab"?? Sounds like a project. Can one man do it? I assume the details of "how to" will be included in my yet-to-arrive service manual.
Thanks loads for all your help!!!
Two nuts and lift. Put a jackstand under the back.
Can one man lift the cab ? ------------if everything is right then easily , if the cab has not been lifted in a long time then sometimes the foam under the seat pan gets stuck to the cowl and I will have to put a 5ft pry bar under the cab and break it loose and then it will go up easy if the gas loaded cab shocks are in good condition , if they have lost their charge it is hard to get it up by yourself ----- I have never block the back of the machine , even with the boom support in the up position without any attachment on it and it is very stable ---- level , hard ground helps
I had a 743 with no bucket on, boom down, cab down tip back when I open the back door in the shop. I put a jack stand under anything smaller the a 863. I have had many 753s reat on the stand with the cab up to the point I could rock the front wheels back and forth. Never hurts to be safe with something with a 30 70 weight spilt.
mahans7
Well-known member
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- Aug 22, 2012
- Messages
- 317
Where do you put the jackstand for the cab when up? Under the cab in the driver compartment?
Back corner of the machine so whole unit won't tip back. If the boom is down, there normally isn't a problem. I will never flip a cab on a 40 series without a jackstand under the back.
Rec'd the manual - the wiring schematic was helpful but I wasn't able to resurrect the machine. (I'm coming around to believe that I will be replacing the computer.) There didn't seem to be anything out of the ordinary after flipping the cab - no mice nests, etc.
The 'unswitched power' fuse was burnt, but replacing it made no difference. I was able to pull the relays, jump the appropriate sockets and get the lights on, the fuel pull to respond, the starter to crank. But jumping the switched power did nothing. I was hoping to get some power to the left dash (BICS) to be able to read some error codes, but nothing
Does anyone know a good bobcat mechanic with the tools to replace the computer in the Chico, CA area, who's willing to make house calls?
You need the dealer to do it, the controller has to programmed using bobcat software. If it is a controller problem, a good tech should be able to verify thats it, replace it and program in about an hout.
jackmcjack
New member
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- Nov 7, 2012
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- 1
I had to change my computer same problem. You only need a dealer to reprogram your hourmeter that is if you want to put the original hours into the new computer. I left mine at 0. ps simple to change I have the old computer board and you can see where it fried a hole in the circuitry for unknown reasons.
there is one other thing that is programmed into the controller of a 753 , the serial number , I seen a few times where this came in handy , a couple of years back a guy got his Bobcat back , it was stolen here in the New Orleans area quite a few years back , it showed in at a Bobcat Dealership in Atlanta for service work and the serial number off the computor linked it with Bobcats Hot line and the guy got it back , rest of the story went that the guy bought it for $10,000 from someone and had a bill of sale , the guy from here had no mercy and flew to Atlanta and pressed charges and sued him personally in civial court for all kinds of stuff like lost of use , transportation back to it's home , depreaciation and damages , I don't how that ever worked out , I don't think that would have gone anywhere
I've had the controller replaced but the mechanic couldn't program it because of more wiring issues, although in my inspection of the wiring it never looked bad (no corroded connections, worn insulation, etc). Everything works except auxiliary hydraulics - I can't open my grappel. The mechanic seems to think I need to replace the main wiring harness (part cost =~ $1,100) but for that price I've gotta spend some time to see if I can fix it myself. My new question relates to running the bobcat with a controller that's not been programmed. The mechanic said he heard that once you put 1.0 hours on it, it can never be programmed. From moving it around, etc I've got 0.5 hours, would like to eventually get it programmed in case I sell it some time, and now I'm afraid to operate it. Can anyone confirm that you can't program a controller once it's got 1.0 hours? Thanks
I personally never heard the 1 hour cut off time , but have heard that the only one that can "scrub " ( reset , wipe clean ) a controller clean is the factory rep
