intelpenel lights blown fuses

[unadilla]

My intel panel lights blow fuses. I have had it to the local dealer and they can't find the fault. I changed the 7.5 amp to a 15 amp. It takes longer to blow but it still blows.

 

[BillyP]

My intel panel lights blow fuses. I have had it to the local dealer and they can't find the fault. I changed the 7.5 amp to a 15 amp. It takes longer to blow but it still blows.

I don't have a clue to your problem but I will strongly suggest that you stick with the 7.5 amp fuse. A fuse is nothing but a safety link and when that link gets broken it's telling you something is wrong. Most likely a short somewhere but shorts (sometimes) are a booger to find.

If this tractor is still under warranty and you fry something due to this 15 amp fuse, most likely the bill will be yours.

 

[AndyMA]

My intel panel lights blow fuses. I have had it to the local dealer and they can't find the fault. I changed the 7.5 amp to a 15 amp. It takes longer to blow but it still blows.

Definately change back to the 7.5 amp. Otherwise you may melt your wiring. How long does it take to blow? Almost instantly, a few mijnutes or significient time. A short will blow instantly. If yo have a short caused by panel movement then the fuse will blow when the panel moves. Take the fuse out and measure the load side of the fuse socket to ground with an ohmmeter and let us know what it is. It nees to be 1.7 ohms or higher. Troubleshooting these issues can be difficult since you can't always get to what you need to measure. do you have a wiring diagram?

Andy

 

[unadilla]

Thanks. It takes about 30 min to blow. The 15 amp fuse was the dealer's idea. I will do the ohm check tomorrow.

Bill

 

[sandman2234]

The dealer could be looking for a way to make this problem go away. If you burn the wiring up by having too big a fuse, he doesn't have to explain why he didn't fix it, and the fact that he "knew" you put a 15 amp fuse in it just gives them something to look for when they try to figure out why it burnt to the ground.
I would do without what ever the fuse was running, rather than have a fuse twice the wires rated value in there.
David from jax

 

[AndyMA]

Thanks. It takes about 30 min to blow. The 15 amp fuse was the dealer's idea. I will do the ohm check tomorrow.

Bill

Electricity does not tend to be most dealer's strong suit. Keep asking questions here if you need more help. Between myself and several other electrical engineers on this site I think we should be able to help you. I will tell you one thing, based on reading posts on this site and may years of experience electricity is viewed as black majic by many.

The fact that the fuse does not blow until 30 minutes indicates an overload condition rather than a short. A short would be immediate. If you can pull the dash I would do that. 7.5amp at 13 v (nominal system voltage) = 97.5 watts. Imagine how much heat is produced by a 100 watt light bulb and that is how much power that is being dumped somewhere in your system That is enough heat that you ought to be able to locate it by touch (be careful not to get burned). At first glance the things that I think of that could use that type of power would be glow plugs and lights. If you have glow plugs I would pull the input line to the and see if the problem persists. You could also check if the glow plugs are on this circuit by measuring the voltage on them and then pulling this fuse to see if it goes away. You'll have to check one circuit after another. On a dash panel I have a hard time imagining that almost 100 watts would not cause a visible burn.

Good luck

Andy

 

[unadilla]

Today I discovered that the fuse that blows is marked on the cover as the Alternator. Isn't that odd?

Bill

 

[RoyJackson]

What brand tractor is this, anyway?

 

[AndyMA]

Today I discovered that the fuse that blows is marked on the cover as the Alternator. Isn't that odd?

Bill

An alternator requires a field current to operate. This fuse could be supplying the field current. Have you noticed that the battery is going dead lately? If this is a small tractor with a small alternator this could be the input point to the fuse panel I suppose. How many fuses are there in the panel/ What is the max size. At this point I'm betting on field current for alternator. You could remove the alternator and have it tested. One way to do a crude test for ths on tractor is to measure the battery voltage as you start it. Prior to starting it should be about 12.0. When you start it should rise to about 13.7 if this system is charging correctly. If you pull the fuse and it is the field current the voltage will drop back to about 12.

Andy

Andy

 

[unadilla]

Andy, I think you got it. I unplugged the alternator, replaced the fuse and the panel lights came on. Could it be a diode in the alternator?

Bill

 

[AndyMA]

Andy, I think you got it. I unplugged the alternator, replaced the fuse and the panel lights came on. Could it be a diode in the alternator?

Bill

Sounds liek you've narrowed ti down to the alternator. For a bried discussion of the parts of the alternator see:
HOW DOES AN ALTERNATOR WORK?

It may be the diodes but it also could be many other things. I would really suggest taking the alternator to a rebuild shop and letting them check it out for you. I think it will be the cheapest route in the long run. You may also just want to look at the cost of a rebuilt unit.

Andy

 

[unadilla]

Andy, If it fried all or part of the alternator what could have caused it? I will take the alternator to the shop tomorrow.

Bill

 

[BobRip]

Andy, If it fried all or part of the alternator what could have caused it? I will take the alternator to the shop tomorrow.

Bill

Another possibility is an intermittent failure (probably a short) Does the failure always take about 30 minutes or is it sometimes much longer or shorter. If it varies then it is most likely an intermittent failure. The failure may only occur randomly or under certain vibration conditions or when the system warms up. I would put a headlamp across (in parallel with) a blown fuse. The lamp will get brighter when the failure occurs. You can them easily monitor the situation. You can wiggle wires, tap things, and let the engine warm up. For example the alternator could be failing when it gets hot. I have used this several times to find problems. It is also very safe. It also helps to have a second person watch the light while you wiggle things.

 

[AndyMA]

Bob gives good advice. I still think that the alternator shop can determine what (if anything) is wrong with the alternator. Assuming the alternator has an integrated regulator that could also be th esource of the problem. Make sure that you tell them that it usually takes itself about 30 minutes to occur.

Andy

 

[BobRip]

Bob gives good advice. I still think that the alternator shop can determine what (if anything) is wrong with the alternator. Assuming the alternator has an integrated regulator that could also be th esource of the problem. Make sure that you tell them that it usually takes itself about 30 minutes to occur.

Andy

My concern would be the shop would test it cold and it only will show a problem when hot. I believe that Andy is alluding to that. Still, if you pull the leads off of the alternator and it does not blow the fuse after thirty minutes of running, that's a pretty good indicator that the problem is in the alternator. Be sure to tape off the loose leads so they don't short to ground when running.

 

[AndyMA]

My concern would be the shop would test it cold and it only will show a problem when hot. I believe that Andy is alluding to that. Still, if you pull the leads off of the alternator and it does not blow the fuse after thirty minutes of running, that's a pretty good indicator that the problem is in the alternator. Be sure to tape off the loose leads so they don't short to ground when running.

I would ask them to use a heat gun on the alternator while they are testing it to bring it up to temp. My guess is that there is some problem that is causing heat all along and that after 30 minutes the problem becomes acute.
Andy

 

[BobRip]

I would ask them to use a heat gun on the alternator while they are testing it to bring it up to temp. My guess is that there is some problem that is causing heat all along and that after 30 minutes the problem becomes acute.
Andy

The heat gun is a good idea and can help pinpoint the problem area.

 

[unadilla]

OK it is back from the shop. It seems to work. He replaced the regulator. I will run the tractor this morning and see if it still works when it is heated up. I did not read your suggestions about heating the alternator when the shop tested it until just now.

Bill

 

[AndyMA]

Good news. The more I thought about it the more I suspected that the regulator was the problem. I'm glad you got out of it without having to buy a new alternator. How much did this set yo back? I expect the heat problem left with the defective regulator.

Andy

 

[unadilla]

I have now operated the tractor all day and everything works. Thanks Andy and Bob for your help. The shop charged $56. The dealer worked on the problem for 6 hours @ $69 an hour! Even taking out the panel and installing one from a new tractor to test the wiring and did not fine the problem. The mechanic did want to know where I got the answer to the problem and I told him of this website. Thanks again.

Bill