Shunt location

Topic: Shunt location (Read 1307 times) previous topic - next topic

Shunt location

April 28, 2018, 04:54:19 pm

Can someone tell me where the starter shunt is located on a 95 u320. And would it keep the alternator from working.

Re: Shunt location

Reply #1 – April 28, 2018, 06:25:28 pm

I don't think there is a starter shunt. The only shunt I can think of would be on an amp meter.

Re: Shunt location

Reply #2 – April 28, 2018, 06:40:29 pm

Don't know about a starter shunt. Are you talking about the starter relay or solenoid? I don't know if anything directly related to the starter itself that would affect the alternator.

Re: Shunt location

Reply #3 – April 29, 2018, 07:12:10 am

Do you mean the splitter from the battery to the isolator and the starter?

Re: Shunt location

Reply #4 – April 29, 2018, 08:13:11 am

The shunt I am refering to is on dwg. B2126. It is between the starter and the ground lug. I think i located in where my coach batteries are. It appears to tie engine batteries, starter, and coach batteries and ties into a central ground lug.

Re: Shunt location

Reply #5 – April 29, 2018, 08:22:04 am

Think were having trouble figuring out the shunt part,will check my drawings,in answer to the question I don't think that would
effect the alternator,which engine and alternator do you have?

Re: Shunt location

Reply #6 – April 29, 2018, 09:05:11 am

Shunt, or just junction where grounds come together?

Re: Shunt location

Reply #7 – April 29, 2018, 11:29:24 am

Like Brett said are you talking about the Black piece with the stud that all the cables come to? If so then yes that could be a problem if those connections are dirty or loose.

Re: Shunt location

Reply #8 – April 29, 2018, 12:17:49 pm

On my '95 U320 power came off the coach batteries through a shunt then distributed into the coach. That shunt was there next to the coach batteries. There was also a large (300 Amp?) fuse before the shunt.

Re: Shunt location

Reply #9 – April 29, 2018, 01:00:25 pm

Those are not shunts. They are terminal connection posts. A shunt is something to read an amp draw.

Re: Shunt location

Reply #10 – April 29, 2018, 01:20:41 pm

Amazon.com: DC AMMETER SHUNT 500 AMP 50 MILLIVOLT: Home Improvement

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Re: Shunt location

Reply #11 – April 29, 2018, 01:36:10 pm

Amazon.com: Positive Insulated Battery Power Junction Post Block 3/8 Lug X...

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Shunt location

Reply #12 – April 29, 2018, 01:50:16 pm

Possibly a picture of the part working lad help us understand.

Re: Shunt location

Reply #13 – April 29, 2018, 03:21:43 pm

John you are correct. That is what Im talking about. I need to check to see why my alternator is not charging. I going to start at the batteries and work through the starter, solenoid , isolator and all connection related to alternator. I will also need to test isolator.

Re: Shunt location

Reply #14 – April 29, 2018, 03:34:50 pm

Easiest quick test of alternator/isolator:

With engine off, check voltage at the two outer lugs of the isolator. They should exactly match the current voltage at their respective battery banks. If not, wiring issue.

Start engine and, using cruise, raise idle to 1000. Check voltage at the two outer lugs AND at the center lug. Center lug should be about .6 VDC higher than the two outer lugs with the outer close to 14 VDC. If so, all is good.

If good voltage (14+) at the center lug, but not at outer lugs, the isolator is bad.

If voltage doesn't change with engine running, may be alternator OR wiring problem. Check the following carefully:

Large gauge wire from alternator B+ terminal to center terminal of isolator.

Ground wire if equipped (some ground through metal connection with engine).

Sense wire-- the small-gauge wire from "somewhere on the chassis battery side of the battery isolator" to sense terminal. An easy one to break.

If an ignition hot wire/terminal, verify that it has 12 VDC positive with ignition on (engine running or not).

Re: Shunt location

Reply #15 – April 29, 2018, 03:52:07 pm

The shunt on my coach looked a lot like the one pictured in post #10.
The amp meter did use it to measure how many amps went in or out of the coach battery bank.

Re: Shunt location

Reply #16 – April 29, 2018, 03:57:28 pm

Quote from: John Duld – April 29, 2018, 03:52:07 pm

The shunt on my coach looked a lot like the one pictured in post #10.
The amp meter did use it to measure how many amps came in or out of the coach battery bank.

Aftermarket, or an option from Foretravel? Not shown in my b-2126 drawing.

Re: Shunt location

Reply #17 – April 29, 2018, 04:56:44 pm

Jim I think the coach was built with that shunt and battery monitor system.
That coach did have some optional items like four outside fluorescent lights. Two on each side and the generator exhaust up through the roof.

Re: Shunt location

Reply #18 – April 29, 2018, 05:09:02 pm

Quote from: John Duld – April 29, 2018, 04:56:44 pm

Jim I think the coach was built with that shunt and battery monitor system.
That coach did have some optional items like four outside fluorescent lights. Two on each side and the generator exhaust up through the roof.

That's cool, just like a Newell!

Re: Shunt location

Reply #19 – April 29, 2018, 10:26:13 pm

what Brett said. as usual a wealth of helpful info.
what the op is proposing is akin to having a light bulb in your house not coming on when the switch is flipped.then starting the trouble shooting at the incoming transformer instead of looking for a burned out bulb.!!

Re: Shunt location

Reply #20 – April 30, 2018, 07:10:02 am

Leaving st. Augustine this morning. Hoping to make it home on house batteries with boost sw. on to keep engine batteries charged. Will check connections later this week and report out. Thank you all for your help.

Re: Shunt location

Reply #21 – April 30, 2018, 09:22:56 am

Start the generator.

Re: Shunt location

Reply #22 – April 30, 2018, 10:14:45 am

Not sure on your engine but last year our alternator died on my 8.3 in Wash.state,made it home without boost switch on,just
charged the start batt every night,just needed juice for the start solenoid and trans.

Re: Shunt location

Reply #23 – April 30, 2018, 11:55:06 am

When start batteries are not being charged by a faulty alternator or other issue, the standard emergency fix is drive with generator running, creating 120v so battery charger charges house battery with 12v, then close boost switch to also have engine battery & engine have 12v. This simple procedure can be repeated each day for weeks of driving until problem is resolved. We and others have done this for extended days.
Do not drive without battery charging as a low battery will kill engine without notice and restart may not be possible without jumping, etc.

Re: Shunt location

Reply #24 – April 30, 2018, 02:19:49 pm

Made it home only about 120 miles. Had generator and boost switch like you all suggested. When I shut engine, generator and boost switch off. I had 12.38volts at the engine batteries. Not bad. Now I will start to look for the problem, after a Johnny Walker or two. Thank you everyone.

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