Looking for some wiring diagrams for an MT345e

[Earthur]

I have an issue with power to the gauge cluster. Sometimes with the key in the Run position it will light up and work normal but most of the time now it all just flashes until i turn on the head lights then it works fine until its turned off. Ive checked grounds and fuses and removed the lower dash for inspection but not found anything yet. Need to track down power to/from the cluster.

 

[Asteral]

MT345HE MT350HE.pdf - should be this version electrical section start on page 625 out of 676

 

[alexpops]

Check the wires coming off the key switch (inside the anti-chafe tubing). Mine was doing that due to water in the tube. There may be a funky short/splice in there.

 

[alexpops]

Did you wind up resolving this?

 

[Earthur]

Did you wind up resolving this?

Nope still doing the same thing. The gauge cluster use to light up when the key was in the on position, that stopped now the gauge cluster itself flickers on and off even after its running for the first 10 minutes or so then works fine.

 

[alexpops]

Another thing to check is all the fuses including the main fuse off the Battery +. I had a bunch of corrosion in the fuse holder there that was giving me intermittent power drops due to resistance until I replaced the whole mess. 12.6v @ battery, 5v at fuse panel & key switch. Obviously check the ground as well ... all LS grounds get funky at the attachment to the frame.

 

[GS650GL]

If it starts working when you turn on the lights, then it is most likely a ground issue. Besides on the battery and negative cable, there are grounds on the clutch housing, firewall, and engine block.. If it has a cab, there are grounds under the roof. It is also possible for all the ground points to be OK, but still have a ground issue because of internal splices in the harness where a bunch of ground wires are spliced together. I've seen high resistance in the splice causing lots of weird symptoms. I tapped into the ground wire in the instrument cluster harness under the dash and added another ground wire and cured it. Also check voltage at ALL the fuses. A bad main relay can cause intermittent low voltage to some of the fuses. It is possible (but not likely) that the instrument cluster is defective. All other things should be ruled out first.

 

[Earthur]

Another thing to check is all the fuses including the main fuse off the Battery +. I had a bunch of corrosion in the fuse holder there that was giving me intermittent power drops due to resistance until I replaced the whole mess. 12.6v @ battery, 5v at fuse panel & key switch. Obviously check the ground as well ... all LS grounds get funky at the attachment to the frame.

I did grind off the paint at the ground by the battery fuse (Clutch Housing) but didnt see anything wrong with that 50 amp fuse. Of course i checked all the fuse in the main panel and all were good. The wiring diagram shows two feeds going into the cluster, one through the controller fuse a 10 amp that then goes through the Relay/horn fuse and to the key switch. The other side goes through the hazard fuse then a 50 amp "Vehicle fuse" (Which i cant seem to find in the docs) then onto the Alternator, I assume that 50 amp fuse is on the battery positive cable gettign charge back from the alt. I suck at electrical troubleshooting and using meters. Trying to get a youtube education on that now. With the key in the on postion and one led on the black wire and one Red /White stripe of the key switch i had 12.6 volts.

 

[Earthur]

If it starts working when you turn on the lights, then it is most likely a ground issue. Besides on the battery and negative cable, there are grounds on the clutch housing, firewall, and engine block.. If it has a cab, there are grounds under the roof. It is also possible for all the ground points to be OK, but still have a ground issue because of internal splices in the harness where a bunch of ground wires are spliced together. I've seen high resistance in the splice causing lots of weird symptoms. I tapped into the ground wire in the instrument cluster harness under the dash and added another ground wire and cured it. Also check voltage at ALL the fuses. A bad main relay can cause intermittent low voltage to some of the fuses. It is possible (but not likely) that the instrument cluster is defective. All other things should be ruled out first.

Thank you- i previously found the ground at the clutch housing and made sure it was good. Where are the grounds at the firewall and engine block? Did you run your new ground wire from the dash back to the one at the Clutch housing?

 

[Earthur]

MT345HE MT350HE.pdf - should be this version electrical section start on page 625 out ofT

MT345HE MT350HE.pdf - should be this version electrical section start on page 625 out of 676

Thank you!

 

[GS650GL]

Even if you have 12.6 at the key switch you can still have low voltage at the fuses because some are powered by a relay, not directly from the key switch. I was only getting 7 volts on a couple fuses when I fixed mine and it was a bad relay. Then another time I had ground issues and added the extra ground wire. The firewall ground is on the right side about half way up the firewall and the wire goes to the clutch housing. I think I attached the extra ground wire at the clutch housing also.

 

[Earthur]

Even if you have 12.6 at the key switch you can still have low voltage at the fuses because some are powered by a relay, not directly from the key switch. I was only getting 7 volts on a couple fuses when I fixed mine and it was a bad relay. Then another time I had ground issues and added the extra ground wire. The firewall ground is on the right side about half way up the firewall and the wire goes to the clutch housing. I think I attached the extra ground wire at the clutch housing also.

Ok so i put this whole circuit on a sheet of paper so i could follow it in the Garage. When I checked the White wire with a red stripe at the key switch i had 12.54 volts, when i checked the top fuse in the box with the key on i only had 11.9 on all the fuses all the way down to the controller fuse. Then i went to the Pink wire at a15 for the gauge cluster and had 12.2.V, when i went to b11 on the gauge cluster i had 11.9. I am not good at electrical stuff so i dont know whats good or bad but it seems i should have 12.54 at the cluster on b11 which is fed from the fuse box right?

 

[Earthur]

How can i test the ground? or should i just run another one and see what happens?

 

[GS650GL]

There can be a slight voltage difference and 12.54 to 11.9 is such a small difference that it doesn't matter. Still pretty close to 12. And if you turn the key on and the glow plugs are on while you test, the voltage will definitely change. When I found my ground problem, I tested resistance with an ohm meter between the black ground wire in the harness under the dash and the negative battery cable clamp. I should have seen zero ohms or pretty close to zero which would indicate good continuity all the way through the harness back to chassis ground. I got about 14 ohms so I knew there was a bad ground splice somewhere in the harness. I had already verified all ground points were clean and tight. I cut some insulation off the harness ground wire under the dash and soldered in another wire and attached it to the ground point on the clutch housing which I already verified was good. Then I had zero ohms on the harness ground when I rechecked it. All the weird problems went away such as dash flickering, gauges not working right, starter clicking when pushing on brake pedals or turning on lights, flashers and work lights on one side dimmer than the other side, etc.

 

[Earthur]

I ran another ground wire to the display ground and it made no difference. Still no power to the display with the key on, and just everything flickers after i start the tractor. I am out of things to check at this point. I ordered another instrument display from Messicks. I read some where that the display has to be programmed, does anybody know how to do that?

 

[alexpops]

The dealer needs to do programming. You won't have the UPLOAD equipment or the files from LS. Before playing parts roulette, you want to rule out bad splices, cold solder joints, corrosion, mouse damage, etc. If you don't have the knowledge or equipment to check the electronics confidently, may be time to have a dealer tech look it over.

 

[Earthur]

The dealer needs to do programming. You won't have the UPLOAD equipment or the files from LS. Before playing parts roulette, you want to rule out bad splices, cold solder joints, corrosion, mouse damage, etc. If you don't have the knowledge or equipment to check the electronics confidently, may be time to have a dealer tech look it over.

Yeah I have ruled out all power and ground issues out at this point. I have around 12 volts on each power wire to the gauge cluster noted on the diagram above. Last ditch effort was a new ground wire to the gauge cluster from the clutch housing ground. Still no difference. There may be something else im missing the cluster
needs to operate but I can't find anything else it could be. Maybe some control or signal wire.. ? Idk

 

[GS650GL]

It is possible the instrument cluster itself is defective now that you have tested and verified other things. On your model tractor i don't think there is any programming that needs to be done with the dealer's service tool. There isn't a computer in the instrument cluster so it should be plug and play. The only things that would need to be programmed would be the ECU for the engine and the vehicle control module if they are ever replaced.