743 fuse keeps blowing

[mkueffler]

after fixing the u-joint problem between the motor and the pump, I have a fuse that keeps blowing instantly. I have checked for a short somewhere and have double checked that all electrical was put back where it came from during the u-joint fix. this fuse works with the three gauges on the right side of the cab. I turn the key to on and the fuse blows instantly. then there is times it will wait until I start cranking over the engine. currently for a quick fix so I can run the machine, I have replaced the fuse holder with a toggle switch. I turn on the toggle switch long enough to start the machine and then turn it off. of course I don't have any gauges that work doing this.

 

[mmsllc]

If the machine only started blowing fuses after the repair, then I would suggest checking all wiring in the immediate area where that u-joint flew apart for exposed wires, or wires that have become pinched together. Assuming that everything there checks out, I would then suggest re-viewing ALL wires (& harnesses) that were taken apart so the engine could be removed. (Those areas would include any "pinch points" such as the cab pivot / hinge area, rear door hinge area & rear door latch area.) If all else fails, unhook everything that connects to the engine, except your battery connections & wiring coming from it, then replace the fuse again to see if it blows. IF it DOES blow immediately, then you have a problem with the wiring that hooks up to the gauge functions (such as the engine coolant temp sensor, fuel level sensor, fuel shut-down solenoid or starter solenoid trigger wire, or key switch) hooked up to power (+) instead ground (-). IF it DOES NOT blow then it was (MOST LIKELY) hooked up to the engine incorrectly & keeps blowing the fuse to protect that circuit. (Doing the diagnostics this way will help rule out the cab area from the engine area & will speed up the repair time, too.) I am guessing the engine side of the harness is where you will most likely find the issue after you do some more double-checking. I hope this helps point you into a direction of finding it.

 

[Tazza]

If the machine only started blowing fuses after the repair, then I would suggest checking all wiring in the immediate area where that u-joint flew apart for exposed wires, or wires that have become pinched together. Assuming that everything there checks out, I would then suggest re-viewing ALL wires (& harnesses) that were taken apart so the engine could be removed. (Those areas would include any "pinch points" such as the cab pivot / hinge area, rear door hinge area & rear door latch area.) If all else fails, unhook everything that connects to the engine, except your battery connections & wiring coming from it, then replace the fuse again to see if it blows. IF it DOES blow immediately, then you have a problem with the wiring that hooks up to the gauge functions (such as the engine coolant temp sensor, fuel level sensor, fuel shut-down solenoid or starter solenoid trigger wire, or key switch) hooked up to power (+) instead ground (-). IF it DOES NOT blow then it was (MOST LIKELY) hooked up to the engine incorrectly & keeps blowing the fuse to protect that circuit. (Doing the diagnostics this way will help rule out the cab area from the engine area & will speed up the repair time, too.) I am guessing the engine side of the harness is where you will most likely find the issue after you do some more double-checking. I hope this helps point you into a direction of finding it.

Sounds like it could the a short on your switched power. When you turn the key, the switched power turns on, I think it's the orange wire, or orange and black.
Just not sure what you could have touched with the engine pull that could do this unless something was put back on wrong, but you checked that already.

 

[mkueffler]

Sounds like it could the a short on your switched power. When you turn the key, the switched power turns on, I think it's the orange wire, or orange and black.
Just not sure what you could have touched with the engine pull that could do this unless something was put back on wrong, but you checked that already.

I finally got some time to work on it. right now I can pre heat for 60 seconds with no problem, turn key on to activate gauges with no apparent problem. but when I start cranking over the motor the fuse blows in about five seconds. I have looked and checked everywhere for shorts. any ideas???

 

[mkueffler]

I finally got some time to work on it. right now I can pre heat for 60 seconds with no problem, turn key on to activate gauges with no apparent problem. but when I start cranking over the motor the fuse blows in about five seconds. I have looked and checked everywhere for shorts. any ideas???

one other quick question, what size fuse is suppose to go in there? I also unhooked the hour gauge and tried it, no difference, so it isn't that.

 

[mmsllc]

one other quick question, what size fuse is suppose to go in there? I also unhooked the hour gauge and tried it, no difference, so it isn't that.

I do not know what that fuse operates or what size it should be. But, after looking at the location of it, it should be powering something such as the key switch, work lights, hour meter or the heater. When it blows, does the machine run? or is that the major issue, that it does not start??

 

[mkueffler]

I do not know what that fuse operates or what size it should be. But, after looking at the location of it, it should be powering something such as the key switch, work lights, hour meter or the heater. When it blows, does the machine run? or is that the major issue, that it does not start??

there are two wires that run from this fuse to the gauge cluster on the upper right corner of the machine. the yellow with brown strip goes to the hour meter, I disconnected the hour meter and no change. the other red and white striped wire goes to the other gauges if this fuse blows, the machine will not turn over, so I installed a toggle switch in place of the fuse so I could crank the engine over long enough to start the machine. once the machine is running it don't matter if the fuse I blown. but I don't have the hour meter and other gauges operational. if this just powers this gauge cluster, I don't understand how it affects the starter. I'm headed to the shop to troubleshoot this some more. thanks in advance for any advice/help here!

 

[mkueffler]

there are two wires that run from this fuse to the gauge cluster on the upper right corner of the machine. the yellow with brown strip goes to the hour meter, I disconnected the hour meter and no change. the other red and white striped wire goes to the other gauges if this fuse blows, the machine will not turn over, so I installed a toggle switch in place of the fuse so I could crank the engine over long enough to start the machine. once the machine is running it don't matter if the fuse I blown. but I don't have the hour meter and other gauges operational. if this just powers this gauge cluster, I don't understand how it affects the starter. I'm headed to the shop to troubleshoot this some more. thanks in advance for any advice/help here!

it turns out that the red and white wire going to the gauges was melted to an orang wire and shorting out. all is good now lol.

 

[mmsllc]

it turns out that the red and white wire going to the gauges was melted to an orang wire and shorting out. all is good now lol.

Good job finding it. I should have suggested opening up the area behind the fuse holder, but thought you might have done that all ready. Be sure to use electrical tape to repair those wires that were damaged, or replace them all together. Fixing stuff is a great feeling. Again, GOOD JOB!!

 

[mkueffler]

Good job finding it. I should have suggested opening up the area behind the fuse holder, but thought you might have done that all ready. Be sure to use electrical tape to repair those wires that were damaged, or replace them all together. Fixing stuff is a great feeling. Again, GOOD JOB!!

thank you, I had checked there but missed it. then I decided to start there and check every inch of wire to the end.

 

[mmsllc]

thank you, I had checked there but missed it. then I decided to start there and check every inch of wire to the end.

From the looks of the picture, it would be easy to miss. You got her right & that is all that really matters. Rock on!