My M6800 blows the 20a fuse whenever the key is switched to the start position. It is fine in Off, on and glow positions but blows immediately when switched to start. We recently replaced the started switch and it worked fine for a short time and now doing it again. Suggestions on where to start tracking this short down?
M6800 Blows Fuse
- Thread starter drack
- Start date
It could be the starter relay or a safety switch that is grounding out because of frayed wires.
Look at the wiring diagram and read the starting circuit description on the attached page.
There are more than one model of M6800 so plse provide your serial number.
Do you have a cab? Does your machine have an Operator Presence controller aka OPC?
Dave
Look at the wiring diagram and read the starting circuit description on the attached page.
There are more than one model of M6800 so plse provide your serial number.
Do you have a cab? Does your machine have an Operator Presence controller aka OPC?
Dave
It is a M6800DT Serial number M680-51219. No cab and I do not believe it has the Operator Presence Sensor. Thanks.
I disconnected the battery cable going to the starter then tested continuity between the other (red) wire going to positive post on starter solenoid and the Black wire on starter solenoid with Key switched to start position and there is no continuity. We checked for bare wires but don't see any.
I disconnected the battery cable going to the starter then tested continuity between the other (red) wire going to positive post on starter solenoid and the Black wire on starter solenoid with Key switched to start position and there is no continuity. We checked for bare wires but don't see any.
I see there is a diode located near the relays.
Any chance you have been boosting the battery or other electrical work just before this problem arose?
I have seen a diode like this fail resulting in a short.
A long shot I agree.
Dave
Any chance you have been boosting the battery or other electrical work just before this problem arose?
I have seen a diode like this fail resulting in a short.
A long shot I agree.
Dave
Attachments
We have not tried to jump it off. It just started blowing the fuse when switch hits the start position. I removed the steering wheel and instrument cluster last night and removed all 4 of the relays to bring back and test. It was really dirty under the instrument cluster and a quick visual look at all the wiring didn't find anything worn or frayed, just dirty. I will try and clean that up today. I wonder if I put a fresh fuse in and plug relays back in and unplug one at a time and see when the fuse gets shot. I will check diode too. Thanks!
I just remembered. Saturday it was running and i took off a mower. Hydraulics working fine. I went to attach a backhoe to it, but the hydraulics for the backhoe would not work. When I tried to move the backhoe in any direction it would just barely move. I was thinking it might be low on fluid so I ran to get some fluid. When i returned, that is when it would not crank and began blowing fuses. I wonder if there is a relationship?
I just remembered. Saturday it was running and i took off a mower. Hydraulics working fine. I went to attach a backhoe to it, but the hydraulics for the backhoe would not work. When I tried to move the backhoe in any direction it would just barely move. I was thinking it might be low on fluid so I ran to get some fluid. When i returned, that is when it would not crank and began blowing fuses. I wonder if there is a relationship?
I'm not familiar with your machine so I will ask, is there a switch/handle that needs to be moved when the hoe is removed or attached? If so, you might have forgotten it or failed to fully activate it. You might also check your quick connections. They sometimes don't fully engage. The fuse thing could possibly involve a pinched wire where you connected the hoe. I don't know where it could be but it's suspect that both problems seem to have started at the same time.
Since the rear of the tractor was involved just prior to the trouble, I would focus on the pto switch as it would be in series with the starter in some way.
Dave
I tested the relays that I knew how to and the switch. Everything seemed fine. I went back and put them back in with a new fuse and it started fine. ??
I did not connect the instrument cluster, lights and hazard lights back up.
I cut it off and on several times. Started fine each time. I engaged the PTO, tested hydraulics, everything fine. I left the PTO engaged and turned it off and tried to started it again. IT started. ??? I didn't think it would start with PTO engaged? If that is correct, then my problem is probably between the switch/relays and the PTO switch. I will look further and reply.
I did not connect the instrument cluster, lights and hazard lights back up.
I cut it off and on several times. Started fine each time. I engaged the PTO, tested hydraulics, everything fine. I left the PTO engaged and turned it off and tried to started it again. IT started. ??? I didn't think it would start with PTO engaged? If that is correct, then my problem is probably between the switch/relays and the PTO switch. I will look further and reply.
You may have had a bad connection at one of the relay spades (or fuse spade) and by you removing the wire and reattaching after testing fixed the problem?