Update:::Unidentified Electrical part on Allegro Bus

[hotjag1]

This part was bolted onto the left rear frame rail beside the transmission. It has a 6 gauge cable(wire) attached to the battery side, and a smaller wire(16gauge)attached to the aux side. Both terminals were corroded, so I was removing the nuts so that I could clean them, but the threaded stud on the battery side started to turn and cracked the housing.
Does anyone know what this part is? I've been told by the RV places that it is either an isolator, relay, or some sort of circuit breaker.

It is on a Freightliner chassis. I called Tiffin, but their tech was busy and I did not leave a voicemail. I'm hoping someone on here recognizes this part or replaced it. I don't know if it is Tiffin or Freightliner

Thanks for any help on this.

[hotjag1]

Update: I called Freightliner and they confirmed that it is a 135 amp breaker that powers up the entire dash and ignition. I found one at Del City for about 2/3rds less than Freightliner or Napa. It will be here in about 3 days.

I do need to clarify one thing: There is a 6 gauge wire that comes directly from the battery to the circuit breaker, but there is "another" 6 gauge wire and a 16 gauge wire that connect to the aux side of the circuit breaker. I originally said that one side only had a 16 gauge wire attached, but indeed there was another 6 gauge cable also.

By the time I came in the house and posted my question(a few hours later)I didn't remember that there was a heavy gauge cables on each side. I only remembered the light weight wire on the one side. It only makes sense to have the same heavy cables on both sides, so I hope this clears up that question. Freightliner did tell me that the 16 gauge wire could go to any accessory that the coach builder needed a power source for.

Thanks again for all the helpful comments and suggestions.

[fcooper]

When you call the Freightliner help desk ( 1 800 385-4357), have the last 6 digits of your vin number handy.

While you're talking with them, ask for a wiring diagram for your specific coach. It will be a big help now and in the future.

Let us know what you finally determine the part to be.

Fred

[rgatijnet1]

It appears to be an older Hi-Amp circuit breaker like this.

Since these came in various sizes I would certainly verify the exact amp rating before you replaced it. Too large and you could have a big fire problem. Too small and it will continue to reset.
Auto reset circuit breaker.

Since you say that it had a 6 gauge wire hooked to one side and a 16 gauge wire to the other, it is probably not functional anymore. It may have been installed for a previous inverter or energy management system that is no longer being used. Certainly a 16 gauge wire cannot handle 135 amps and 6 gauge wire is only rated for around 60 amps.
I would either NOT replace it or verify with an electrical diagram for YOUR coach exactly what it was used for. If you are right about the gauge of the wires that are attached to it, it IS NOT 135 amps.

[YC_1]

hotjag1 wrote:

BobGed wrote:
I would suggest you send your photo to Don Boyd at Tiffin, don.boyd@tiffinmotorhomes.com Ph: 256-356-0261 Ext 3824. He should be able to identify it in seconds.

I contacted Don Boyd at Tiffin, and he was almost certain that it was a circuit breaker rated at 135 amps. He also told me that this circuit powered up the dash and the ignition switch. He did say that this was a Freightliner chassis part and to contact Freightliner to get 100% verification on it and that they could supply it for me.

Thanks BobGed for the contact info for Tiffin.

Disconnect it and see if the dash is dead, that way you know for sure.

[BobGed]

hotjag1 wrote:
I contacted Don Boyd at Tiffin, and he was almost certain that it was a circuit breaker rated at 135 amps. He also told me that this circuit powered up the dash and the ignition switch. He did say that this was a Freightliner chassis part and to contact Freightliner to get 100% verification on it and that they could supply it for me.

Thanks BobGed for the contact info for Tiffin.

You're welcome. Don is very knowledgeable on most all things Tiffin. Hope Freightliner can take care of you.

[hotjag1]

BobGed wrote:
I would suggest you send your photo to Don Boyd at Tiffin, don.boyd@tiffinmotorhomes.com Ph: 256-356-0261 Ext 3824. He should be able to identify it in seconds.

I contacted Don Boyd at Tiffin, and he was almost certain that it was a circuit breaker rated at 135 amps. He also told me that this circuit powered up the dash and the ignition switch. He did say that this was a Freightliner chassis part and to contact Freightliner to get 100% verification on it and that they could supply it for me.

Thanks BobGed for the contact info for Tiffin.

[hotjag1]

Thanks for all the good replies. The general consensus seems to be that it is a circuit breaker. Problem is that there is no amperage marking or part # of any kind on it. I agree, it needs to be waterproof also.

Thanks for the link to Don Boyd at Tiffin. I will send a picture to him as I would like an identical replacement.

[mccsix]

A plain ol' terminal to attach any ol' accy

[BobGed]

I would suggest you send your photo to Don Boyd at Tiffin, don.boyd@tiffinmotorhomes.com Ph: 256-356-0261 Ext 3824. He should be able to identify it in seconds.

[BB_TX]

Don't go guessing as to what it is based on comments here. Make sure you KNOW what it is before installing something in its place. Even if it is an auto reset circuit breaker, do not replace it with one of the cheap ones from the auto parts store. Most, if not all, of those are not water tight. Mounted on the frame near the transmission it would need to be water tight. That one in the picture appears that it probably would be.

[wa8yxm]

Another argument in favor of circuit breaker over diode isolator

NO HEAT Dissipation fins.

Diode isolators develop heat,, a fairly large amount of it, so they have fins.

[azrving]

With looking at one picture my guess is circuit breaker. 16 g wire is only good for about 20 amps max so that breaker shouldn't be over 15 amps or so. I would replace it with a type 3 manual reset. Those automatic types are fine until you have a fault that makes it keep tripping. If it continues to trip, it finally goes into melt down and welds to the ON position and takes out the wiring harness. Not real common but I have seen it a few times. It's cheap and easy to just upgrade to manual reset. I would agree to find out what is on that circuit before determining the breaker size.

The reason another 16 gauge wire may be on the side with the large wire is because they ran a hot wire to another device.

One example

2

[RoyB]

l would contact TIFFIN Allegro Bus with photos and location of the component.

Being only two connections marked BAT and AUX I would lean towards a BATTERY SYSTEM component and most likely a DIODE BASED ISOLATOR. However most DIODE BASED ISOLATOR requires THREE LARGE CONNECTIONs if used in the POSITIVE TERMINALS of the battery systems..

This could very well be high current AUTO RESET RELAY CONTACTOR.

I have been scanning the internet without any good results. Was even able to look through a couple of USER MANUALS PDFs for the Tiffin Allegro Bus.

I am just guessing like all the others here...

Roy Ken

[YC_1]

While it is off, try to find out what does not work. Be sure to insulate the wires of course.