I have a Bobcat Ct 335 tractor, I'm having problems with my electrical system. I have no headlights, tach works when it wants to, 4 wheel drive light stays on all the time, very dim, except when I switch it to 4 wheel drive, then it goes out temp gauge works until you set the parking brake, could this be in the computer, or maybe a rat has been eating on the wiring, now when I turn the lights on to try them the fuel pump clicks and the engine shuts off, I have cleaned the safety switches at the parking brake, and the neutral switch, but that didn't help any, thanks for your help....... I think this is a Dae Dong or Koeti tractor with a Bobcat name on it.......
tractor electrical problem
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Fuddy1952
Elite Member
- Joined
- Apr 17, 2018
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- 4,333
- Location
- South Central Virginia
- Tractor
- 1973 Economy and 2018 John Deere 3038E
On our old 50s-60s cars when we have multiple electrical problems I think bad ground which it usually is, so I would either check those (battery-- , frame to motor, etc.) or check with voltmeter.
With it off across battery if it's 12.5v (normal), leave -- neg. lead side on then with key on (but not running) lights on, check grounds...motor block, frame, etc. and you shouldn't measure voltage (Maybe 0.1v is all).
Next would be corrosion at connectors. Then like you said rats, ground hogs chewing wires. Carefully look where it's parked for pieces insulation or wire.
With it off across battery if it's 12.5v (normal), leave -- neg. lead side on then with key on (but not running) lights on, check grounds...motor block, frame, etc. and you shouldn't measure voltage (Maybe 0.1v is all).
Next would be corrosion at connectors. Then like you said rats, ground hogs chewing wires. Carefully look where it's parked for pieces insulation or wire.
Thanks for the information Fuddy1952, hoping its something simple like a grounding issue, but with my luck it will be something BIG, I'll check it today if the rain lets me, and let you know what I found........ Thanks again.
atsah
Elite Member
Weird, my guess is you have a bad ground also..
Trails End
Gold Member
I think that you'll find that the problem is the
switched power relay - the relay shown in
the attached photo as the "eroneously labeled"
timer relay. It's item 5 in the photo below.
I've had to replace this relay twice now in the
last five years. It's failure (intermittent or continuous)
results in the same symptoms that you have described.
Good luck, and please let us know what the final
resolution is.
switched power relay - the relay shown in
the attached photo as the "eroneously labeled"
timer relay. It's item 5 in the photo below.
I've had to replace this relay twice now in the
last five years. It's failure (intermittent or continuous)
results in the same symptoms that you have described.
Good luck, and please let us know what the final
resolution is.
Last edited:
atsah
Elite Member
It's always good to have someone with the same tractor that has had the same problem and fix it..
Trails End
Gold Member
In case this might help, shown below are the electrical schematics for the CT335
electrical system. I've highlighted the parts of the circuit that are fed from the
switched power relay which is the probable cause of your problem.
electrical system. I've highlighted the parts of the circuit that are fed from the
switched power relay which is the probable cause of your problem.
The hole keeps getting deeper , I took the cover off the tractor to look for the relay you had told me about, I checked the relays the way the manual said and they checked out good, now the engine stops running when I try to turn on the lights or when I try to switch to 4 wheel drive, hour meter stopped working and tach only shows reading at higher RPM's doesn't read more than 10. I was hoping this would be an easy/simple repair, but now I'm wondering..... I'll look at it again today and see what else I can mess up, Thanks for all the support and help. Trails End......
Fuddy1952
Elite Member
- Joined
- Apr 17, 2018
- Messages
- 4,333
- Location
- South Central Virginia
- Tractor
- 1973 Economy and 2018 John Deere 3038E
Now I would check grounds. Weird electrical problems usually manifest like that. Everything takes two wires, hot and ground. If there is a bad ground then something getting power will find a ground through something else. Example is you turn a light on...it's dim and something else comes on because that's the path to ground. Another suspect would be connectors, especially ones with a lot of wires...corrosion either poor connection or trace between two pins.
I would disconnect battery , then use electrical contact spray. Take your time.
Also look at wiring for rubbed places.
You say no headlights, so start there. Battery disconnected unplug a light, either check resistance or simply use clip leads to jumper it over to battery...be sure bulbs are good. Then check switch, spray it...temporarily connect battery...wiggle wires.
Disconnect battery and check grounds...clean and tight contact. Over the years I have found broken wires easily by gently pulling on them. If a wire is broken sometimes you can't see it...but insulation will snap with a gentle pull where wire is broken. The main thing is taking your time, and one thing at a time. Check...disconnect, clean, reconnect, move forward.
I would disconnect battery , then use electrical contact spray. Take your time.
Also look at wiring for rubbed places.
You say no headlights, so start there. Battery disconnected unplug a light, either check resistance or simply use clip leads to jumper it over to battery...be sure bulbs are good. Then check switch, spray it...temporarily connect battery...wiggle wires.
Disconnect battery and check grounds...clean and tight contact. Over the years I have found broken wires easily by gently pulling on them. If a wire is broken sometimes you can't see it...but insulation will snap with a gentle pull where wire is broken. The main thing is taking your time, and one thing at a time. Check...disconnect, clean, reconnect, move forward.
