Light switch

This question is asked way too soon without all of the information. I want to know anyway! Can a light switch operate but cause blown fuses periodically?

886. I put two additional work lights on it a couple years back. This fall I was fertilizing with it ("field" lights on) and it blew the fuse for the lights. I replaced the fuse and it would run the "road" lights fine without blowing the fuse so I didn't tempt fate and just used those to finish. I looked and thought I found a loose connection where I had added the lights that may have grounded out. I replaced the connector and all was well. This winter I have noticed the switch getting picky about where it had to be for the lights to come on so I kept meaning to pick one up the next time I was at CIH. Two nights ago it blew the fuse with the work lights on again. I replaced it and only used the road lights to chore (with those stupid flashing lights annoying me the whole time). Last night I got in it and could get the flashers to work but no others. If I wiggled it just right I could get the front road lights to flash but not stay on. I was so mad I used another tractor to chore and put the new switch on the RIGHT NOW list. I didn't even check to see if it blew the fuse but I'm doubting it since I could sometimes get them to come on with creative wiggling. I'm in the house for the night or I would go look at that fuse.

Do I have two problems or can a bad switch blow a fuse?

It is possible by adding the 2 extra lights you have overloaded the switch and circuit. Anytime you add lights in parallel circuits, the resistance goes down and the total amperage goes up. You may have to put the work lights on a circuit by themselves with another switch someplace. By increasing the amperage, you could also be overloading the light switch contacts causing them to burn. I would use a clamp on ammeter and test your total amperage draw when all the lights are on. The test is done using the power wire that supplies power to the light switch. Compare it to the fuse that is suppose to be in the circuit. You may find the amperage is almost equal to the fuse which could cause the fuse to heat up and eventually blow. This is one possible cause since all the lights stay working until you turn on the extra lights.

I just gave in and went and looked. It's not blown. I'm guessing it was the switch all along.

Correct since you could get the lights to turn by wiggling it, but the extra lights may burn up the new switch also if it has too much amperage. The switch could have had bad contacts, but they would not cause the fuse to blow unless they were touching the case somehow. Bad contacts reduces the amperage causing low light brightness. So do watch the fuse and if it blows again, it would be wise to check the amperage flow before you burn up another switch.

Two solutions: Put LEDs on place of the lights you added (and the normal lights as well if you want to see very well.
The second is to use a common electrical rela=y to supply voltage to the extra lamps. The wire now going to the lamps turns on the relay, and the lamps use electricity through a 25 amp fuse or circuit breaker from the battery positive. Jim

If that switch is the same as on the 06/56 series tractors and I think it is, then it had marginal current carrying capacity when new. Add a bunch of years of use, dust, dirt, corrosion and some added lights and you have problems. The battery terminal on these switches is the weak point,they will overheat and corrode. Check yours. I'll bet it is badly corroded if it has never been replaced. Replace the terminal on the end of the wire also. As Jim says, put your additional lights on a relay and if you want to make it really bulletproof put all the lights on relays.