TC25D - Fuse #5 Blowing

SteveInMD · Jan 22, 2009

I should point out that this fix is not something I dreamed up. It's a standard method of making starting circuits more reliable on equipment with complex starting circuits such as lots of safety interlocks or very long circuit runs such as yachts. I don't know exactly what is wrong with the original design, but I do know that I've not burned up any more fuses, ignition switches, or glow plug timers since I made the change.

Drue · Jul 30, 2014

It's been awhile since you had a problem. Could you send the wiring diagram? I have a 2003 TC33D that keeps blowing #5 fuse.
Thanks,

Halftrack · Jul 30, 2014

Here is the wiring diagram for your TC 33. I had the same issue that started for no apparent reason. Retracing my steps prior to the repeatedly blowing the 30 amp fuse, I found I had removed the ignition key and reinserted it upside down and that is when the problem began. I now have it marked with a top and bottom and have not had a blown fuse since. Other suggestions for the problem is a self-resetting circuit breaker in place of the fuse and possibly gong to a 40 amp fuse that the later models have. BUT FIRST check the key.

sparc · May 1, 2016

Halftrack said:
Here is the wiring diagram for your TC 33. I had the same issue that started for no apparent reason. Retracing my steps prior to the repeatedly blowing the 30 amp fuse, I found I had removed the ignition key and reinserted it upside down and that is when the problem began. I now have it marked with a top and bottom and have not had a blown fuse since. Other suggestions for the problem is a self-resetting circuit breaker in place of the fuse and possibly gong to a 40 amp fuse that the later models have. BUT FIRST check the key.

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Can you explain how the orientation of the key causes the fuse to blow? I am researching a repeated blown 30a fuse on my TC25 and came across this thread.

In my case I went to start the tractor last week and had no power like a dead or missing battery, no lights, nothing had power. Last time the tractor ran and I put it away without incident. After locating the cause (or so I thought) I got a replacement 30A fuse and installed it. When I turned the key to energize the glow plugs the fuse popped in less than 2 seconds. It was cool (about 50°F) that day. So two blown fuses with no apparent reason I am looking for answers before I put another fuse in. I've had the tractor a couple years and never popped any fuses, don't understand why now without warning this fuse blows.

Halftrack · May 1, 2016

I can not explain why the up-side-down key makes a difference and can not see a noticeable difference in one side compared to the other, but it obviously makes a difference in the start switch. I do know that if I tried to start the tractor today with the key up-side-down, it will blow the 30 amp fuse. I went through a box (5-6) of fuses before I retraced my steps and reversed the key.

sparc · May 11, 2016

I will have to experiment and see if this holds true for my TC25.
Can you tell me which way is up (as silly as that might sound) on your key?
What about other Ford/NH keys, did you have the same problem using other
keys.