Electrical Problem - II

[DFW]

Hi all, sorry for the delay, had in-laws visit and was forced to go up to Lake Tahoe and do some spring skiing. Now, if you remember my original post:
<font color="blue"> It seems whenever I turn on any of my lights (headlights, marker lights, working lights, signals) and the tractor is running, my tachometer stops. Also, with the tractor not running, if I switch the lights on the ammeter jumps to the positive side. Any help of where to start looking would be much appreciated. FYI, the ammeter never goes negative... </font>

Well, the saga continues... I've replaced the instrument cluster, dealer suggestion, as I couldn't get to the tack leads as suggested, to test it. So, polished the frame where the negative connects to make sure I had a good ground. Still got the problem!!! /forums/images/graemlins/shocked.gif Tested the generator with no connections and the tractor running, 4.7 volts output, hmmm, not good. So, I asked the dealer for a new generator/regulator. Installed it, still no output with new generator/regulator /forums/images/graemlins/confused.gif (all wires disconnected from the generator when tested BTW). OK, now what? Tried tracing wires, gave up when they disappeared into the wiring harness never to be seen again. Checked the fuses (did before, but what the heck). Curious, looks like two hot leads coming into the fuse block, one feeds all the circuits and has an outbound side and provides current for all the accessories. This line has a 5a fuse (which is blown). The other connection is just a one-to-one connection, does not feed anything else on the fuse block and is protected by a 30a fuse (it's ok). So, I replace the blown 5a with the 10a from the signals (won't be on the roads for a while), plug that in where the blown 5a was, start the tractor, the generator is generating /forums/images/graemlins/smile.gif(my meter reads 13.5v), but the now the ammeter burys itself to the negative side. /forums/images/graemlins/crazy.gif I know something's wired wrong here but don't posess enough knowledge to know what and don't want to burn the thing down. I'll talk with the mechanic tomorrow, but just thought y'all might have been here before.

 

[JimR]

Ammeter should go negative when the lights are turned on with the tractor off. The wires on the ammeter are backwards.

 

[DFW]

Jim, agreed, but I am a little hesitant to switch them since they came connected that way on the new instrument cluster (just like the old one too).

 

[AndyMA]

</font><font color="blue" class="small">( Tested the generator with no connections and the tractor running, 4.7 volts output, hmmm, not good. So, I asked the dealer for a new generator/regulator. Installed it, still no output with new generator/regulator /forums/images/graemlins/confused.gif (all wires disconnected from the generator when tested BTW). )</font>

Just wanted to clarify a few things. What you are attempting to test is a alternator, not a generator. The alternator generates AC which is converted to DC via a set of diodes. An alternator will not generate any electricity without having a field voltage applied. In other words an alternator will not work unless it's field terminals are connected to a 12 v source of DC (battery). DC Generators used quite a few years back did not require a field voltage. As far as the rest of the problems, I suspect that the ammeter may be connected in backwards, but I also think you probably have another thing or two miswired. (or a defective component).

Andy

 

[DFW]

Andy, thanks that was what I was thinking too. In the Chinese translation to English they call it a generator in all the manuals. So, I went on that premise... /forums/images/graemlins/frown.gif

 

[Junkman]

When all reasonable things seem to be correct after having been replaced, replace the ignition switch. This is where all the connections are made and where most things can get "mis wired" without being detected and there is no way to know for sure. It is a simple task and is one of the first places that I have learned to look when things suddenly go bad. If the wiring was correct last week, it doesn't get crossed this week unless someone deliberately does this. The same goes for other components of the machine. Since you are the only one that operates the tractor, the chances of this happening is nil. The chances of the ignition switch going bad without any outside intervention is very plausible.

 

[JimR]

Without seeing what your panel looks like, I have to guess that the + and - wires to it are backwards since the ammeter was not changed. Your ammeter pegs negative because your alternator is putting out the max right now. It should be buried to the positive. Never replace ANY blown fuse with a higher number fuse than what it calls for. The circuits are made to blow a certain amperage fuse if there is a problem. Using a higher amperage fuse is a big no-no. Years ago I fixed quite a few idiotic mistakes due to people wrapping a blown fuse with a tin foil gum wrapper or putting a cut nail in for a blown fuse.

 

[MossRoad]

<font color="blue"> Never replace ANY blown fuse with a higher number fuse than what it calls for. </font>

I agree. It's very easy to smoke a wiring harness by using larger than original fuses. /forums/images/graemlins/shocked.gif /forums/images/graemlins/mad.gif

 

[DFW]

Totaly agree, I only switched the fuses to see what would happen if I had working fuse in that slot. I do not intend to run it like that. Thanks for the hint on the ingition switch, I'll pull that out next.

 

[DFW]

It's fixed /forums/images/graemlins/grin.gif!!! Thanks to all the TBN'ers that offered their suggestions. Jim, I switched the wires on the ammeter, held my breath and started the tractor and everything works great. I guess the factory doesn't know + from -... FYI, I've got the proper fuse in the slot.