TC40DA Blows #5 Fuse After 15-30 Minutes

[dakota52]

jinman,
Thank you for help and patience in helping me troubleshoot my problem. I feel your pain about troubleshooting from a distance. I am often asked to call customers at work (we make electric/hydraulic vehicle lifts) to see if I can help them get their equipment back up and running. The most frustrating part is knowing that if I was there in person I could probably find the problem 10X faster than having to work over the phone.

You are right that I am getting off track to look at components outside the hi-shift circuit. I do not blow the #5 fuse unless the transmission is in rabbit so it must be in that circuit. I guess the frustration of chasing this problem got me moving too fast and not thinking things through. I will pull the diode pack in the next couple of days. If it looks suspicious at all I will order a new one and let you know if that fixes things. You are right that the diode pack plugs into a socket just like the relays near it. I will also look over the high shift relay socket and see if I notice anything there. I appreciate the help in knowing where to look.

 

[dakota52]

I pulled the diode pack off the tractor the other day and ordered a new one. It was marked "Dill Blox 100690" on the outside of the plastic case. I was a little shocked to see that the dealer wanted $67 for such a simple looking part. I decided to see if I could source the part elsewhere and found it for only $15 at Dill Blox Diode Module 100690 6A 1000V 100685 100686. They had about 150 of them available so it looks to be a reliable source of this part. I should receive the diode pack later this week and will try it out once it arrives and then post an update

I also wanted to let everyone know that I found a good alternative range solenoid coil instead of spending $450+ at the dealer for the whole range solenoid assembly (I still can't believe they don't offer just the coil and make you buy the whole thing). I had started researching this a couple of weeks ago and was glad when I found out that the range solenoid coil wasn't causing my fuse to blow. I figured since I had a couple of coils that looked like they would work I would go ahead and try them and report what I found. I borrowed a HydraForce 6352012 coil from work to see how it fit and worked. I installed it on my tractor today and it fit and worked perfectly. It shifted fine and I didn't notice any difference between it and the factory original. I checked the resistance of the coil and it checked at 7.2 ohms so it is pretty close to the original one on that as well. The best part is that I found the coil available on the web from several sources such as http://www.hydraulicstore.com/index.php?loc=items_detail&data[history]=&data[catalog]=1&data[itemcode]=7014959 for under $20. The only modification required to use this coil is that you have to leave off the metal case that goes over the original. So it may not be quite as well protected, but for the price you can buy an extra coil and still come out way ahead.

 

[dakota52]

Good news. I got my new diode pack the other day and put it in. So far I have run the tractor about 3 hours in rabbit and have not blown the fuse. So it looks like my problem is solved. Jinman, thanks a bunch for your help with this.

 

[jinman]

Great news Tom, and thank you for the info on a bargain source for the parts. It's amazing how much money you can save by shopping the web.

 

[dakota52]

I know it has been a while since I last posted on this thread, but I wanted to post an update on my TC-40DA (Hopefully this doesn't break a rule about posting on old threads). After replacing the diode pack the tractor did not blow the #5 fuse for a few weeks. However, the weather cooled off here during that time and I was working without the A/C on. When it heated up again and I was using the A/C I started blowing the fuse again after about the same 15-30 minutes of use.

I finally found that the problem all along was a couple of wires with damaged insulation. The wires are located under the hood near where the two large plugs pass through the firewall from the cab (on the right side of the tractor as you sit in the seat). The wires are close to some A/C lines and when the A/C ran condensation collected on the damaged wires allowing them to short to one another. After repairing the wires and putting all of the wires in that area in some loom the problem has gone away for good. I am really glad this problem is solved. Just wanted to let everyone know how I finally fixed this problem in case anyone else is fighting the same thing.

 

[jinman]

Tom, it would be interesting to know what those wires are going to since they must pull power from fuse #5. Since I don't have a "with-cab" schematic, it's a mystery to me. Perhaps the power is to lighting inside the cab.

 

[dakota52]

Jim,
The wires are going from the relay block under the steering wheel out to the high range shift solenoid coil. They pass thru the firewall on the right side (almost directly behind the relay block) in one of two large round plugs. So it made sense that the fuse would only blow when the rabbit/turtle switch was on rabbit since that was the only time this wire had power to it. It took a combination of the rabbit switch being on and the A/C causing condensation on the wires to blow the fuse.

 

[jinman]

I understand where it was now. Thanks!

 

[docyandell]

My New Holland TC 40 DA has started blowing the 7.5 amp number five fuse. This takes out my high speed range (rabbit/turtle switch) and cruise control. The tractor starts fine and will run 15-30 minutes before the fuse blows. I have looked for a frayed wire but haven't found any. I tried changing the high range shift relay and that hasn't helped. Can the diode be bad? I will appreciate anybody's suggestions. This is getting very frustrating. Up until now the tractor/cab had been fine.

Dakota, my New Holland does the exact same thing only blows fuse in 2 minutes. Have taken it to dealer many times which helped it for a few days and it starts all over. Did you ever figure out what your problem was? docyandell

 

[dakota52]

The AC water condensation was shorting out under the hood where the AC lines and wires go into the cab firewall on the right side. It was barely a nick in one wire where it went thru the cab firewall that caused the trouble. A simple wrapping of waterproof electrical tape over the wire group solved the problems. However, it caused many grey hairs before the headache was found. Good luck on finding your short!