Battery isolator relay broken

Edmather · May 05, 2014, 03:49 PM

Hi,
So on the first run after the improved door, I ended up on the side of the road.
Got back to the D19 after shopping, turned the key: got nothing at all. No power to the dashboard, no clunk from the starter.
So did some checking and narrowed it down to the switch over thing next to the battery. No idea what it is called, and it seems to be absent from all of the wiring diagrams too! There was no power forward of this unit. When checked there was a massive drop in current across it.

This was the culprit.

So, after a few checks, the AA guy reckoned that it was ok to by-pass, and sure enough the winnie started straight away. We were only about three miles from home, so things looked good.

So here are the questions: What is this thing called? And any idea where I can get another?

On a side note: I also noticed just before the bypass, that the indicators weren't working, nor was the fuel gauge. Post by-pass both were good, until a very hot smell up the hill, then not working. I can't figure how they are linked. Common positive earth?

Thanks.
Ed

Stripe · May 05, 2014, 05:19 PM

Solenoid

Any decent auto parts shop..

This looks close to yours.

Basically it's a powerful electromagnetic switch. So what could be wrong with it is the wire wrapping inside could have been shorted out.

DaveVA78Chieftain · May 05, 2014, 06:44 PM

100 amp Battery Isolator Relay. Do not let anyone tell you a standard starter relay will work. They are not designed for constant duty operation.

Dave

Stripe · May 05, 2014, 07:37 PM

So, not an auto solenoid to be sure.. But a Constant duty Solenoid?

I forgot to address the gauges. As far as I know, the ground is negative. and yes they all share a common ground which is usually the chassis.
The solenoid itself is also grounded to the chassis by virtue of being mounted to it in some way. Usually bolted to a frame section. The picture Dave posted shows the mounting bolt as ground.

circleD · May 05, 2014, 07:53 PM

BOOM! Dave had a diagram Stripe

Those solenoids are a nice extra piece of mind to isolate batteries but you have to remember that they are there. I've ran into that several times.

DaveVA78Chieftain · May 05, 2014, 10:01 PM

They make 2 styles
The 3 terminal version where the mounting bolt is ground. Used when mounting to a metal frame.

The 4 terminal version where a seperate terminal is used for a ground wire. Used when mounting to wood or fiberglass.

Either version can be used as long as it is grounded properly.

QuoteSo, not an auto solenoid to be sure.. But a Constant duty Solenoid

Yep, Constant Duty Solenoid.

Dave

Oz · May 06, 2014, 12:01 AM

Had to replace mine. $34 at the time, as I remember. OEM was made by General Dynamics. It was widely used in military applications. I replaced it with the 3 terminal version and sawed-off the EOM mounting bolt, which was welded to the battery box and rusted pretty badly. I replaced it with a stainless bolt, washers, and nut.

Edmather · May 06, 2014, 03:59 PM

Hi,
Thanks for the information everyone. Glad the bit doesn't sound too hard to find.

Came up with this:

http://www.intellitecmv.com/index.php/products/Power_Management_and_Distribution/Battery_Isolators_and_Contactors/Contactors_100_Amp

Look the right sort of thing?

Ed

DaveVA78Chieftain · May 06, 2014, 07:29 PM

Battery Isolator Relays are available at any RV store, many auto supplies (plow blade support), Farm Stores, EBAY, etc. It is not a hard part to locate.

Dave

TerryH · May 07, 2014, 12:48 AM

Common for serious 4X4's with winches and dedicated winch batteries as well.
T

PwrWgnWalt · May 07, 2014, 05:13 PM

Hi Ed,

The Intellitec solenoid is a very capable piece, I used them for my electric system overhaul and have been very happy with them. You may find it is more than you need - it has fused monitoring leads. See post #23 of my in-progress post (2nd post from bottom of page 1) here:
http://www.classicwinnebagos.com/forum/index.php/topic,6765.0.html

The easiest route for you, and cheapest, is likely to replace it with a three-post constant duty solenoid similar to what you have pictured. Widely available, as Dave and others note.

Unsure about your gauges, unless the lead wires were shorting from the emergency wiring done.

- Walt

Edmather · May 19, 2014, 04:00 PM

Hi, new shiny relay in and looks just the job. She even starts!
Once again thanks for the help.
However the other things looked ok, until I went to come back into the house this evening and found the headlights and taillights on, even though everything was off. I even disconnected the dash switch, and they stayed on! Oh joy!
There will be various other 'help' threads shortly!
Ed

Mytdawg · June 28, 2014, 09:58 AM

I've got something similar under my dash that's hot and has juice on all 3 poles with the key off. When I connect the battery I hear it switch on and it's draining the battery. Like it's hot wired (and it may be). What I don't know is if it's malfunctioning or hooked up incorrectly. There has been some mutilation under the dash. PO took power wherever he could find it. I'm assuming that is also some kind of solenoid. Most searches for ignition solenoid take me to the starter and that doesn't look right. Ignition relay or module also doesn't seem to find what I'm looking for. What the heck is it? Thanks!

Mytdawg · June 28, 2014, 11:32 AM

Well it doesn't appear to be much of anything. I disconnected it and the RV still runs and the only thing that stopped working was the radio. Lord only knows what it used to be for. Probably at least one of the no longer functional dash switches...

DaveVA78Chieftain · June 28, 2014, 02:12 PM

Quote from: Mytdawg on June 28, 2014, 09:58 AM
I've got something similar under my dash that's hot and has juice on all 3 poles with the key off. When I connect the battery I hear it switch on and it's draining the battery. Like it's hot wired (and it may be). What I don't know is if it's malfunctioning or hooked up incorrectly. There has been some mutilation under the dash. PO took power wherever he could find it. I'm assuming that is also some kind of solenoid. Most searches for ignition solenoid take me to the starter and that doesn't look right. Ignition relay or module also doesn't seem to find what I'm looking for. What the heck is it? Thanks!

Used as aux power source from coach battery when key is ON. Power to small post should not be there with key OFF. Was a Winnebago addition, not part of the Dodge original chassis. I also have one mounted to the forward bulkhead under the dash.

Dave

Mytdawg · June 28, 2014, 03:52 PM

Oh dear, I have no coach battery and I got juice on the first pole on chassis power. I disconnected the switch lead. It was wired directly off hot on fuse box of course. Where is the next likely spot working back toward coach circuit that it's possible to be crossed over? Assuming the dipstick didn't accidentally jumper the two together somewhere... I've pulled several feet of wire and scotchlocks out already. Is that a function of the isolator solenoid? Since I'm aware that the chassis is compromised I haven't even attempted to light the coach side yet. Now that I think about it, he could have bypassed the chassis and be running it all off the coach side. Yuck. That would be epically stupid but it would explain his exploratory search for power. Thanks for the endless patience and knowledge Dave.

DaveVA78Chieftain · June 28, 2014, 06:28 PM

Let me double check mine. I am going by memory on it being coach battery.

Dave

Mytdawg · June 28, 2014, 07:46 PM

I'll have to try to get a better idea of where the cables underneath all go so I can formulate a meaningful question. Every time I think I'm getting close it throws me another curve. I found several instances where he had tied so many positives together it was effectively a parallel. Everything was probably getting 6 volts. I'm hoping he didn't take that a step farther...

pvoth1111 · June 28, 2014, 07:55 PM

Previous owners ROCK!

DaveVA78Chieftain · June 29, 2014, 09:52 AM

I checked mine. The battery source is the chassis not house battery. Solenoid is only energized when the key is ON. If I recall correctly, I believe this is the voltage source for the dash heater motor.

Dave

Mytdawg · June 30, 2014, 01:47 PM

Alright, maybe it's not completely jacked then. Thanks for checking. I figure if I pull enough of his stuff out I'll hit a point where I can start making things work again. I'll obviously have to get more familiar with the architecture, such as it is. Like learning pig Latin, won't have anybody to talk it to but you guys (and ladies).