Electric problem: a real mystery

[K7JV]

I asked your question of a friend of mine in Ft Myers, and he shared the following:

Rick Horner
Horner’s RV Service
941-575-7254
He is about 12 miles north of Fort Myers on US 41

I do not have personal knowledge of him, but an old friend passed that along to me, for you. He likewise doesn't have personal knowledge, but he said, "my sources say ...".

Since no one else chimed in, it might be a great starting point. And we're all looking forward to finding out what turns out to have been the root of your problem.

[zmotorsports]

Originally Posted by BT-III

Note to Vanwill: I do not know what an ignition contactor looks like. Please send me a picture.
So the problem remains and I wish at this point someone could recommend a knowledgeable technician here in the Fort Myers, Florida area.

Thanks again!

This is what a contactor will look like. These look like the old Ford starter solenoids but these are continuous duty relays, contactors or solenoids. Common terminology for them. They are the silver items to the right, below the echo-charger in this picture and are orientated with the "tophat" upright as Van mentioned.


This picture was taken at my rear engine bay panel but there should be 2 or 3 of them in your front run panel just in front of your left steer tire. Each one feeds different circuits, I would check these first as they can be intermittent and then fail completely.

Mike.

[Vanwill]

Originally Posted by zmotorsports

This is what a contactor will look like. These look like the old Ford starter solenoids but these are continuous duty relays, contactors or solenoids. Common terminology for them. They are the silver items to the right, below the echo-charger in this picture and are orientated with the "tophat" upright as Van mentioned.


This picture was taken at my rear engine bay panel but there should be 2 or 3 of them in your front run panel just in front of your left steer tire. Each one feeds different circuits, I would check these first as they can be intermittent and then fail completely.

Mike.

Louis, thanks to Z-Mike, you now know what the "solenoids", "relays" or "contactors" look like. I'm sorry I cannot refer you to anyone in your area, but if you feel comfortable replacing one of these contactors, they are not expensive, and not difficult for even an amateur to replace. Find (Amazon, DelCity.net, etc.) a version that is CONTINUOUS DUTY 12VDC, has the same number of terminals as yours and is listed as having SILVER contacts. These silver contact versions are much better at handling light loads. The reason I suggest replacing these things blindly is that intermittent electrical problems are the pits to diagnose. Sometimes, your only reasonable recourse is to begin "throwing parts at it", starting with the least expensive ones.

http://www.texasindustrialelectric.com/pdf/SAS_4202.pdf Here is an example which is about $55. The ones with silver contacts are nearly double the price of copper contacts. I think you need only concern yourself with the ones in the Front Run Bay. HTH

[zmotorsports]

In reference to Van's post above, if you merely want to replace them with a direct replacement continuous duty relay you can go to your local NAPA store and purchase an ST85 but it will not have the silver contacts like Van mentioned.


Mike.

[BT-III]

Thanks to Jim, Mike and Van.

I have two of those located in the Front Electrical Panel. They are White Rodgers W 70-111224-5 COIL 12VDC CONT.

They are mounted sideways, with one 'top' in the direction of the front of the Coach , the other with the 'top' looking towards the rear.

Is there a way to find out if one is indeed defective before removing it?

At this point, the Dear Wife want's me to quit this ghost chase for the X-Mass time.

I will get back to it after New Year day. We are parked here until April so time is not a factor for now.

Merry Chrismas and Happy New Year to all.

[YC1]

I just posted this on another thread.

The solenoid is a very basic dumb device. It has a coil that voltage is applied to via the small terminals. One gets voltage and the other is for a ground. It indeed will clunk when energized. It will also get very warm or even hot to the touch if energized for a long time. This is normal for this type of solenoid.

If you have the voltage on one of the small terminals and no voltage on the other you can lift one of the small wires off and touch it on and off to hear the solenoid slamming a piece of metal between two contacts inside.

Those contacts are a very common source of failure. I keep a spare solenoid because of the failure rate of them.

They can be intermittent as heck, when energized you should have the exact same voltage on each of the large terminals.

[Yaj]

Private message sent

[jacwjames]

Car Circuit Tester DC 6V 12V 24V Voltage Auto Vehicle Gauge Test Light Green | eBay

Go to Walmart or an auto parts store and get a 12 volt test light. With this you can check to see if 12 volt power is going through the solenoid.

Does all the chassis power seem to be off when you are having this problem?? I was having a problem with my rig earlier this year, I would turn the key on and the dash would go dead, flip it off then on again and it would start. Ultimately I lost all power to the dash and found the rotatory chassis power disconnect switch bad.

There are acutally 2 of these on my rig, one for the chassis & House, looks like this.


http://www.ebay.com/itm/Guest-Switch...VV14nn&vxp=mtr

[clifford j]

Hi Louis, wish I was with my friends in No. Ft. Myers this year, I'd come over and give you a hand.
The important clues you gave are devices that Monaco did NOT install ,they are part of the original chassis wiring installation. I don't know what chassis the Monaco Company built on but that's the direction I'd head. There may be items Monaco installed that share the same power source. Don't let the after market items that became inoperative cause confusion.
The ignition switch was a great start ,it has a couple of circuits that it turns on. Some of those circuits activate relays which in turn supply powe to various components. There is a commonality to the items that have failed ,that is a great clue to start your search. Not having a volt meter is a drawback. You can but a cheap one from a bunch of stores for less than 10 bucks. I would start by testing the fuses for voltage ,not just looking for a blown fuse. The small black cube relays are another place to look. Identify what relays operate the items not working and see if they are in trouble. Sometimes you can flip flop relays to see if you have a defective one. If you pull one of the relays look at the bottom where the prongs are, you will see the contact identification. 30 is the power contacts and numbers like 87 /86 are for I think the coil .I'm a little fuzzy trying to remember with out being there.
I 'm retired now from being an automotive repair center owner for 25 years.
Hope this gives you some help

CLIFF

[zmotorsports]

The best way to check for the condition of the contacts in the relay is to do a voltage drop test across the load side of the relay. If there is any resistance it will show up under a voltage drop test.

That is probably the quickest and simplest test I can think of.

Mike.

[zmotorsports]

Originally Posted by clifford j

Hi Louis, wish I was with my friends in No. Ft. Myers this year, I'd come over and give you a hand.
The important clues you gave are devices that Monaco did NOT install ,they are part of the original chassis wiring installation. I don't know what chassis the Monaco Company built on but that's the direction I'd head. There may be items Monaco installed that share the same power source. Don't let the after market items that became inoperative cause confusion.
The ignition switch was a great start ,it has a couple of circuits that it turns on. Some of those circuits activate relays which in turn supply powe to various components. There is a commonality to the items that have failed ,that is a great clue to start your search. Not having a volt meter is a drawback. You can but a cheap one from a bunch of stores for less than 10 bucks. I would start by testing the fuses for voltage ,not just looking for a blown fuse. The small black cube relays are another place to look. Identify what relays operate the items not working and see if they are in trouble. Sometimes you can flip flop relays to see if you have a defective one. If you pull one of the relays look at the bottom where the prongs are, you will see the contact identification. 30 is the power contacts and numbers like 87 /86 are for I think the coil .I'm a little fuzzy trying to remember with out being there.
I 'm retired now from being an automotive repair center owner for 25 years.
Hope this gives you some help

CLIFF

Just for clarification, Monaco DID install these relays/contactors in the front run panel. They were installed after the coach body was built on the chassis.

Also just for clarification, Monaco coaches were built on a Roadmaster chassis, also built by Monaco. Roadmaster was a division of Monaco and each chassis was specifically built for the coach it was going on. The start and run circuits are not "aftermarket" per se.

Mike.

[clifford j]

Thanks Mike for the clarification. MHO is that chasing these massive solenoids as a culprit is not the right direction to search.

CLIFF

[larry koenn]

Louis, I've had your same problem with two different motor homes in the past 15 years. Both times it was the run solenoid. It's possible to turn the key off and on many times while watching the voltage gauge and get a better connection. When the solenoid gets corroded it develops a voltage drop due to resistance and you only get partial battery voltage to the dash and running services.

The easy way to determine which is the run solenoid and the one giving you the problem is to turn the key on while watching for low voltage on your dash gauge, and then lightly tap the two solenoids, one at a time, while DW watches the dash. She should see fluctuations when you tap the offending solenoid. You can also correct the voltage and improve the contact by taping the solenoid but it will only be temporary. Tap the solenoids with a small hammer or maybe a good sized screw driver handle.

Before trying to remove the run solenoid all power must be shut down, both chassis and rv battery switches off and also remove ac power so the invertor is not supplying 12 volt power.

I've always replaced the solenoids with part store items but make sure you are getting a continuous duty solenoid. A starting solenoid will burn out in a few hours.

Good luck and let us know what you find.

Larry

[Vanwill]

Originally Posted by clifford j

Thanks Mike for the clarification. MHO is that chasing these massive solenoids as a culprit is not the right direction to search.

CLIFF

Cliff, that would normally be a good assumption and good advice. But these solenoids are long known to be a common failure item in Monaco coaches. Many, if not most, folks completely bypass the one non-technically known as the "Salesman Solenoid", which cuts all 12VDC power to the coach. It was such a frequent failure item that it became the "first place to look" if you lost 12VDC power in the coach. Monaco also probably made a poor choice in the solenoid for the dash instruments (too large and no silver contacts) and they SURELY mounted it in the incorrect orientation, according to the manufacturer. That sideways actuation exacerbated the problem of trying to connect a modest load through a huge contact.

But I'm sure the OP appreciates your suggestions. When one is chasing an intermittent electrical problem, you want all the input you can get. Thanks for helping.