Bobcat S450 Electrical Problem

Bobcat S450 Electrical Problem Problems

Hello everyone here… Having a major issue with my Bobcat S450 loader (gas). Was working the machine with no problems. Turned it off to have discussion with home owner. Went to turn the machine on and it wouldn’t start.

The history is as follows:

1. Using battery charger, jumped from the left of the starter solenoid, engine started but no controls or BICS indicator lights.

2. Had already been having a problem with starting prior so I went to John Deere and bought a replacement 6 prong ignition switch. It appears to be the same exact switch right down to the patent number stamped on the side. Still no start.

3. Lifted off caps for fuse block and apparently the cap had a hole in it, because it was full of water. So water splashes out. I dry that up and the BICS controller fuse is blown. Replace that and it blows right away.

4. Start checking all fuses with a voltmeter and find the 15amp engine fuse is blown, even though it looks good. So I replace that and engine starts but still no controls.

5. After study of the wiring diagram, I removed the BICS unit and opened it. Circuit board was burned – verified by sight and smell.

6. Got a replacement BICS unit from local repair shop. Guy explained that there are different units due to Bobcat discontinuing the seat sensor. Assured him that I did NOT have the seat sensor. I have the green push-to-operate switch on the left control panel.

7. Installed the replacement BICS unit. Now the motor will start with the key but still no controls. BUT, the fuse is NOT blowing now. I guess I’m getting closer? I get the power light and sometimes the seat and seat bar lights flash. Also, the key will not turn off the machine.

8. The two BICS units have different Bobcat part numbers.

9. Also, when the machine rpm is lowered, by the choke or throttle, from normal to low all lights on the BICS will light solid intermittently, but never stay on for more than a split second. I appreciate any help or advice that anyone can give. Thanks in advance.

Welcome. I would suggest you call your local bobcat dealer and get the part number to confirm you got the right BICS unit. A faulty or improperly functions BICS panel will cause a multitude of problems. After that, I would start with the simple stuff. If your Fuse panel was soaked with water and it were me, I would just bite the bullet and replace all the relays. Having been thru Katrina, Rita, and Ike in south louisiana, If there is one thing I learned its that submerged electronics will let you down sooner or later. If not sooner, for SURE later and typically when its most inopportune. Even electronics dunked in fresh water have poor reliability and since you were able to splash water out of your fuse panel, i would call it as good as submerged. While everything was out, I would spray it down with CRC 2-26. Its an electrical cleaner/lubricant/corrosion inhibitor. It works wonders for electronics and leaves a film that inhibits corrosion but is non-conductive. After that, I would ferret out all the grounds (not just battery ground, but all the chassis grounds), clean and redo them. By the time you get done with all that, it might accidentally work right.If not, you may have run across something that is just as visibly bad as your BICS panel was. With all the flickering and dimming and whatnot, it sounds like a power supply problem, versus a controlling component problem. The thing that strikes me is your key not turning off the machine. Thats a bit of an odd symptom when you look at it with the rest. You may want to trace THAT specific problem, and whatever is causing the remaining symptoms might be related to that, or you could have simply wired the switch wrong, but either way I would think that circuit would be the easiest to trace. If you cut the power, it SHOULD shut off, especially if its a gas unit.

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