Reefer 15 Amp Fuse Melting Down

**Denny_A** · 07-22-2003, 06:29 PM

Greetings,

I just removed my SECOND 15 Amp DC Reefer Fuse tonight. The first one went a couple of weeks ago. The latest one was used, just once, to supply DC power for the DC mode of the reefer and reefer fan during a 1 hour tow. The reefer worked fine then.

After installing an ammeter a few days ago, I turned on the DC mode of the reefer to record current draw. Saw about 11 amps. Today, while on shore power, I tried the reefer in the DC mode and the tubes carrying the coolant did become quite hot, confirming proper operation. When I removed shore power, reefer still on, the ammeter was dead on zero. Checked the coils - stone cold.

Immediately, popped open the converter panel and, sure enough, the 15 Amp reefer fuse ruptured, but not before the plastic on the upper leg of the fuse melted, ran and exposed the metal along the entire fuse leg! Happened the same way last time. Also, this time, there are burn marks around the upper female connection into which the melt portion of the fuse was inserted.

This does not seem good. ??? I am open to suggestions (actually pleading) folks. Traveling with an inop reefer can't be a good thing. Where to begin. BTW, the reefer fan is on the same fuse/circuit. It's the 5th fuse from the left on the DC portion of the fuse panel.

Looking for TM/DC experts here :-\ .

Denny_A

**mjlaupp** · 07-22-2003, 07:17 PM

The problem is in the connection to the upper leg of the fuze. The connection was loose and has overheated the connection. It is now weak and contaminated by oxidation. You will have to replace the faulty connector or most likely you will have to replace the entire 12v fuze panel board. A job for a qualified repairman.

Not good news, but that is my take on the situation.

MJL

**Bill** · 07-23-2003, 09:51 AM

Denny -

I am confident that Mike is right about a bad connection on the fuse board. You can buy an exact replacement fuse board from BR-Wholesale (http://www.brwholesale.com). Their on-line catalog lists it as
"6 + 3 FUSE BOARD (3200, 6300 SERIES), BRW number 1-30506922".
Delivery is fast, cost is (gulp) $40 + probably $10 postage.

Their web site is a mess. I would suggest that in the end, you use their toll-free number to order.

I'm sending a private message on this topic.

Bill

07-23-2003, 10:37 AM

But, $50.00 is a whole lot cheaper than paying to replace a burned TM :'(. You should probably double check the condition of the existing wires. Overheating this bad could cause brittle wires that could lead to a fire. Just my $.02 worth.

ColoradoCop

**Denny_A** · 07-23-2003, 10:51 AM

Mike and Bill and COCop,

Thanks to each of you for your reply.

Bill - I was able to get the fuse board on the BR Wholesale site. Am ordering the (gulp) board.

I'm guessing it needs to be installed and wiring checked by a "professional"(as Mike and COCop stated ). I tend to do my own electrical work - but, this is definately a case for which my insurer would balk at reimbursing me if the trailer were to burn to the ground following an electrical catastrophe (if I had made the repair}

.

Again, thanks for the quick response.

Denny_A

**BobWilson** · 07-23-2003, 01:18 PM

If it was me, I would try to pull the fuse board out a little without disconnecting the wires and see what the trouble is. Maybe you just need to replace one of the crimp-on connectors on the end of the wire that plugs into the connector on the board. Or maybe the connector on the board just needs a squeeze with needle nose pliers to make it tighter. Maybe you just need to tighten one of the terminals at the top of the board.

If you have to replace the whole board I'd take pictures so you are sure to get all the wires back in place. The TM manual does have a wiring diagram, I do believe. Make sure the wires are labeled if you take them off. This doesn't sound like too hard of a job for someone who has done a little electrical work before. Sounds like a fun job.

Bob W.

**Denny_A** · 07-23-2003, 04:55 PM

[quote author=BobWilson link=board=2;threadid=1034;start=0#msg7211 date=1058987930]
If it was me, I would try to pull the fuse board out a little without disconnecting the wires and see what the trouble is. Maybe you just need to replace one of the crimp-on connectors on the end of the wire that plugs into the connector on the board. Or maybe the connector on the board just needs a squeeze with needle nose pliers to make it tighter. Maybe you just need to tighten one of the terminals at the top of the board.

---------snip-------
Bob W.[/quote]

Bob, et al,

I've decided to proceed one step at a time, using caution and standard troubleshooting procedures; then, order the board, if need be. Will post the result when finished -- unless I need to return here for more "hep" first. :P

Denny_A

**mjlaupp** · 07-23-2003, 08:45 PM

Bob,
I have been working in the electronics and controls industry for years. I have not seen a friction connection like the one used on the this fuze that will hold up after severe overheating. The temper is gone from the metal and in some cases the metal composition is changed. The only sure and safe repair is to replace the connector. Usually this requires an ORU (Optimum Replacement Unit) to be installed. In this case it would be the "(gulp) board". The wire that connects to the back of the terminal on the back of the board should be cut back and stripped to provide a fresh contact area, and if a connector is crimped onto the end of this wire, it should also be replaced. Any attempt at repair by bending/squeezing the connector or tightening a screw connection would at best provide only a short term solution. This would do for an emergency repair while on a camping trip but the permanent, long term repair would have to be replacement of the connector/(gulp) board.
MJL

**Denny_A** · 07-24-2003, 11:31 AM

Mike,

Thanks for your additional input. I am paying close attention and will be belt/suspenders cautious (to borrow from a Site Sponsor). Having been (during thr dark ages) a metalsmith, I can relate to "loss of temper". A bad thing! 8)

Denny_A

07-24-2003, 05:01 PM

I'm by no means an expert on electrical stuff, but at first thought, I'd kinda wonder if one of the connections in the back of the board might somehow be touching the side of the converter case (which is grounded) causing a short. Agreed, I'd have the whole board replaced, but I wonder if that's what actually caused it. I bought a brand new Interstate Deep Cycle battery biggest one I could find and installed it. A few months later, I noticed it wasn't working at all. (It had been sitting plugged up so the converter was charging the battery). So, when I discovered this, I simply unhooked the two wires, and it was a bit dark in there when I did it and didn't notice anything. I took it back, and got a free replacement, but noticed this peculiar black mark going down the side of it. When I went to put it back in, I made sure I had lots of light. Knowing that red is hot, and black is ground usually in a DC system, and faced with a white and black wire, I simply thought, well, the black wire was ground when I first hooked up the battery that died on me. After putting more light on the subject, I had found I had wired it backwards, and the wire coming off the positive battery post had burnt off every bit of insulation.......ALL THE WAY BACK ALMOST TO THE CONVERTER ITSELF! (AKKKKKK!) I showed it to my dad, and he replaced all the wire with the proper gauge and all, and got it all hooked up the way it was supposed to after I pulled up the converter from the floor under the couch. (He knows a LOT about those sort of things, and even once built a radio station from scratch for his old college back in the days of the tubes. At any rate, I definately learned my lesson there.....had it caught the TM on fire, I'd have not only lost it, but as close to my house as it is, probably would have lost my house as well! At any rate, I would definately let a professional take a look at it and do the job right as the possible outcome can be a complete disaster!

[glow=red,2,300]Happytrails............[/glow]