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Farmall 656 electrical problems


BOOMER LANDT

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OK , first off before the trip to RPRU in Ohio everything worked without any problems at all except air filter restriction gauge . When I unloaded & parked it everything was OK . Thursday morning I went to start it for the parade and the troubles began . I turned the key on and glow plugged just fine . When I hit the starter button it rolled over for a few seconds and quit . While I sat there pressing the button to try again , smoke rolled up from behind the tach/speedometer (Hydro) :o .

I ended up unhooking battery cable at the starter to avoid anymore problems and jumped the solenoid from there on out to do the parades & load on trailer for trip home . Tonight I tore into it and found the wiring for the air filter restriction gauge were melted . This gauge mounts below headlight switch and always went to red even with new filter . I removed gauge and wiring and taped off wire that goes to air filter and put everything back together and hooked up battery cable .

The key does not do anything when turned on and the starter button does nothing but the glow plugs work . The 3 positions on the light switch are all messed up . The first click gets me the amber flasher , red tail part of rear light and RH side dash/gauge lights . The second click gets nothing and the third click gets the inside fender lights :blink: .

Could it be that it ruined the key switch , starter button & light switch ? Hate to just start throwing parts at it but I need it at night next weekend for a wedding hayride . Thanks in advance .

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You need a good test light and follow the voltage, key on power to starter switch, gauge cluster, air cleaner indicator. If your good with wiring, I recommend a complete rewire from scratch. The problem with the original harness is none of the harness plugs are weather proof, dirt dust and water penetrates these and creates contact issues that lead to hot spots and then burned wires or fires.

I built mine with 14g wire and ran wire from point a to b, no plugs. I also used 4 wire trailer wire for fenders to enable a ground wire from fender to chassis. Any plugs used were the modern weather proof ones, I even found the wire wrap all purchased from McMaster Carr.

If your not great with wiring Porsche electric has all the replacement harnesses to fix you up.

Also using your favorite search engine will find you a pretty good diagram, as I recall C&G has harness diagrams uploaded.

Scott

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Check voltage drop across your key switch and starter button. Sounds like you have a short somewhere in the air restriction gauge circuit or the switch is bad. I dont know if it is an NC or NO switch but you can un hook the wires and ohm it out. I would get an electrical diagram for the tractor it will help you out a lot.

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The key switch should have 12v coming in to it, turning it on powers the starter button. The glow plugs are on a completely different circuit independent of the switch and guages. ( except the gp meter) Did the lighting circuit fuse blow? It sounds like you have a short under the dash area that has resulted in the light switch being "back fed" and has caused an open circuit to the starter button. As mentioned, use a test light to trace where you have 12v, coming in to the key and coming in to the light switch and try to find out where the open circuit is.It sounds like when you saw the smoke a wire "burned off" and that maybe the one that was supplying 12v to the key or between the key and starter button. Have fun! :mellow: Been there.

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Sorry for the delay but we are on a last minute July 4th mini-vacation . Thanks for the replies and wiring diagram .

The only wiring that was burnt/melted was the air restriction gauge and I removed all of it to help make room to see . One weird thing I saw was 1 wire from that was hooked to 1 terminal on the starter push button . The fuse is good for the lights and I have some of the lights/flasher so the switch is kinda working . When I get back home I will do some testing and post what I find .

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Update time . I had some time today to look at key switch and took off RH side hood panel . Both wire ends at the switch were melted and key switch looks burnt :( . I do have one wire with power and the other wire has a problem down line at the dash fuse holder . It seems to have melted solder that used to hold 2 wires together at female connector at the fuse .

Next time I'm going to wire key switch wires together and splice fuse wire back together and see if that gets things back closer to normal . I'm really leaning towards a whole new wire harness after Saturday's hayride . Also am considering installing master switches to avoid fires <_< . I'll keep you posted .

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OK , here's the run down :

  1. Key switch ruined
  2. Both wire ends at key switch melted
  3. Hot wire to key switch rubbed thru coolant gauge lead
  4. Double wire into single female end at light fuse came un-soldered
  5. Air filter restriction gauge wiring melted
  6. Road lights in fender wire unplugged from connector

Got everything done in time for hayride last night and it worked fine B) .

I removed air filter gauge all together and am still puzzled why it had one wire going to starter push button <_< .

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