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nplenzick · 03-23-2010, 12:46 PM

This is the solenoid that controls most of my main distribution panel that relates to the chassis. When you turn the key on the solenoid closes there by supplying 12 volts to dash and pretty much everything else related to the chassis . When this solenoid fails it's a catastrophic failure. By this a mean you lose power to everything, motor dies, no lights, brake lights, four way flashers, just about everything. It happen to me once when I first bought this coach right down the road where I live and had to have it towed to a truck repair where they replaced it with a "heavy duty" type. All was fine until this past summer, when we were returning home the dash warning lights would start to flick on an off and my back up monitor started acting weird. I suspect that solenoid as these were some of the things it would do before it first went out. Put a new one in and took the old one apart and found it to be burned on the power coming in side. All was fine again until this past trip, while traveling down I-95 in North Carolina I saw my ATC light come on and stay on. Usually when that comes on it's a sign that a filter is clogging but this wasn't the case this time. A few minutes later my TV monitor started to go out and shortly after the coach died. Lucky for me my buddy was following me in his pickup and helped keep traffic from plowing into me. Once we got it to the side of the road it started and I drove it to a rest area where I replaced the solenoid with the spare that I carry. All is fine again.
The photo's I attached are of that failed unit. It only has about 6000 miles on it. You can see the burned area that I believe is causing the problem. I thought it could have been from a bad ground so I even ran a #2 wire right to the grounding block in the panel and another ground from the panel to the frame. Apparently that's not it.
While in Daytona Beach FL I stopped by a NAPA dealer and bought the heaviest duty solenoid that they have ST85 ( it actually weighs 3 oz more then the others). That's what I have in right now but I'm still paranoid that this two will go at sometime. I'm thinking of running two solenoids at the same time. Does anyone think that would be a problem? Also on the switch side ( the two small terminals) there's a resistor or capacitor of some sort installed be Monaco. Does anyone know what that does? When I asked Monaco tech support they said as long as the engine shuts off when you turn the key off then you don't need it. When you check it with a meter you get no resistance or continuity. Any suggestions or ideas are appreciated.

nplenzick · 03-23-2010, 12:51 PM

Don't know where the photo's are so I'll try again

Mike Canter · 03-23-2010, 02:54 PM

The NAPA ST-85 is a continous use 80 amp solenoid vice a starter solenoid which cannot stay on for a long time because it will overheat. We use the ST-85 a lot in professional drag racing to control the nitrous oxide systems and never have a problem with them. It is a great choice for replacement. The capacitor that you are talking about is to help stop relay chatter. We never had a problem with them chattering. Well hooking two of them in parallel would work but sooner or later one would die and you wouldn't know it until the other one died and then you would be stuck again. Having two in parallel would help spread out the current flow so they would not arc so much when tutning on or off. Like I said we use these a lot without a problem and there are a lot of NAPA dealers around. I would just carry a spare just to make you feel better.

ShapeShifter · 03-23-2010, 03:20 PM

Quote:

Originally Posted by Mike Canter

Well hooking two of them in parallel would work but sooner or later one would die and you wouldn't know it until the other one died and then you would be stuck again.

That would be my concern, as well. You would have to periodically test them to make sure both are working. Otherwise, while you may extend the time between failures, you won't eliminate failures that leave you dead.

Quote:

Originally Posted by Mike Canter

Having two in parallel would help spread out the current flow so they would not arc so much when tutning on or off.

It may help reduce the continuous current that one solenoid sees, but may not stop the arcing. I would guess it's unlikely that both will switch on or off at the same instant. When pulling in, I think one will be more likely to make contact first, and there will be an arc at that point. Same with turning off, first one will break, and when the second breaks there may still be an arc.

______________________

How common of a problem is this? I've not heard of it before (but that doesn't mean anything!) Since stepping up to a larger solenoid didn't fix things, before I started doubling them up I would want to know why they keep burning up. Seems to me that there is some unusual load that is either causing a high inrush current, or there is some heavy inductance that causes a bad arc when turned off.

Twomed · 03-23-2010, 03:33 PM

I've replaced several on coaches with the ST 85, and never have had to go back on the issue. It's just a better/heavier unit. Your problems should be over.

nplenzick · 03-23-2010, 03:33 PM

Quote:

Originally Posted by Mike Canter

The NAPA ST-85 is a continous use 80 amp solenoid vice a starter solenoid which cannot stay on for a long time because it will overheat. We use the ST-85 a lot in professional drag racing to control the nitrous oxide systems and never have a problem with them. It is a great choice for replacement. The capacitor that you are talking about is to help stop relay chatter. We never had a problem with them chattering. Well hooking two of them in parallel would work but sooner or later one would die and you wouldn't know it until the other one died and then you would be stuck again. Having two in parallel would help spread out the current flow so they would not arc so much when tutning on or off. Like I said we use these a lot without a problem and there are a lot of NAPA dealers around. I would just carry a spare just to make you feel better.

Thanks for the reply and you confirm what a Freightliner dealer told me when they did some work on the MH in Lake City FL. The solenoid that's in the photos is from a Volvo truck. I'm not sure what their rated for.According to that dealer the St 85 does not have a copper washer but a silver one instead.
My concern is when this fails, sometimes you have very little warning. Kinda like flying a plane loosing power and now you have to find a place to land. I use this MH a lot for my business and I drive all hours of the day many times I'm by myself. I was lucky this past time, next time it could happen on a bridge, tunnel, or any place where there is no room to pull over.
A friend suggested if I add another to also add a switch to the switch side of the solenoid, that way if one does fail all I would have to do is throw a switch on the dash and I would have power again.
This whole thing seems odd to me though, has anyone else had this problem?

ShapeShifter · 03-23-2010, 03:43 PM

Quote:

Originally Posted by Twomed

I've replaced several on coaches with the ST 85, and never have had to go back on the issue. It's just a better/heavier unit. Your problems should be over.

Oops, I missed that part -- I thought the ST-85 had already failed, and he was on the second one. That was the basis of my previous comments, maybe they make more sense now?

Mike Canter · 03-23-2010, 05:04 PM

If you look into the top of that solenoid that you have taken apart you will see that the copper washer is not hitting flat on top of the contact terminals that are attached to the bolts coming out of the sides. Actually if you look carefully the contact area on the bolt is rotated in the direction that the nut was tighten to hold the bolt so only a corner of the contact was hitting the washer. It would sure seem to me that when they tightened those nuts they should have kept those terminal straight and then it would have lasted longer. In a pinch if stuck out in the middle of nowhere you could loosen the nuts and turn the bolts in the opposite direction to make a new contact area with the copper washer.

wa8yxm · 03-24-2010, 11:04 AM

I carry a short jumper cable.. If the solenoid fails.. I jumper it.

True story.. Very old true story... Some years ago a carpet cleaning company was trying to get a contract with the Battle Creek (Michigan) Public Schools. This company used a truck mounted Wet system to deep clean the carpets.

They soaked down the carpet with cleaning solution and hit the start button on the Wisconsin Engines V-4 in the truck to suck it up as it were.

CLACK: but no Rrr Rrr Rrr VARROOM

Solenoid was bad

I removed the starter side wire from the solenoid and using pliars "Slammed" it against the battery side.. Thus.. They were able to suck it up.

They lost the contract... but at least they did not have to replace the carpet in the boardroom at their expense.

gg · 03-25-2010, 01:52 PM

What chassis is this solenoid on, where is the box/ solenoid located?
thanks gg

nplenzick · 03-25-2010, 03:59 PM

Quote:

Originally Posted by gg

What chassis is this solenoid on, where is the box/ solenoid located?
thanks gg

It's a diesel pusher, not sure if a gasser has anything like that.

BURR-HEAD · 07-21-2011, 04:07 PM

I had a similar problem except mine was intermittant failure. I got the ST85 replacement, my husband took the old one off without defining where all the wires went. Do you have a diagrahm of the wiring, or where they go. I spoke with Monaco, and know where all go except a small red wire coming down from the ignition in the dash. Does it go where the orange wire is or on the copper band strip where the med size red jumber goes from the left side post to the copper band strip?

timdriver · 07-21-2011, 08:02 PM

I've got a Safari pusher and have never had this problem but I will now go to the NAPA dealer and purchase a spare.

rpasetto · 07-22-2011, 06:03 AM

My Dynasty uses White-Rodgers solenoids, #70-11224. (see DC Power Solenoid, 12V, Amps 80 - DC Power Solenoids - Solenoids - 6C028 : Grainger Industrial Supply)

Note that they are rated 80a, "continuous" duty. I have a few in the front run box and also in the rear RH side box. Over the years a few have failed, after all, nothing is really "continuous" forever

. It's worthwhile to carry a few spares.

Whatever the case, make sure the relay matches specs, e.g .continuous duty 12v NO, 4-pole. Some of the higher amp rated ones might last longer, if they'll fit. for example...
Search 12v dc power solenoid - Grainger Industrial Supply

and ...
ASE Supply Outlet Store