No generator

[dshinnick]

Calling all maintenance wizards!

We have an '05 Holiday Rambler Ambassador with an Onan/Cummins QD8000 generator. It is currently dead; no signs of life at all. Last time this happened I was advised to check the power connections at the rear of the unit. I did that just now. There are two, a red and a black. I put my trusty multimeter on them, and nada...nothing.

I assume these leads go back to the battery compartment and tie into the house batteries somehow. Everything back there looks clean and snug, and all other power to the coach is normal. I can run a continuity test and try to trace the cables from the generator to the battery compartment, but I'm not sure if that's the correct strategy. And, I can't find any circuit breaker which might be at fault, other than the one on the generator itself, which I have turned off and back on.

Thoughts?

Thanks-

Dave

[dshinnick]

Ok, the latest.

I cleaned and re-connected the power connections and I have 13v there.

I took the top off the gen and don't see anything disconnected.

I tried starting it, and when I pushed the Start button, I got a light, like I was supposed to! I was most impressed. But, it went out after a few seconds, and never did attempt to crank.

I got the 3 blinks indicating a service fault. I pushed Stop, and tried everything again, but nothing....dead. I can't even get the service fault blinks back.

So, I'm about to break out the credit card and call a service guy, unless someone has another idea. Last time this occurred, a few years ago, I think the guy spent about 5 minutes with the cover off, and said "found it. A connection was loose". I didn't think, at the time, to write it down and take pictures. Wish I had. So, that may be all it is, but I don't know anything else to check. Do you?

Thanks-

Dave

[dshinnick]

UPDATE:

I feel kinda silly, but I always used my multimeter around 120v systems, and when there was power, the multimeter vibrated and sounded a tone. So, I just assumed (hate doing that), that it would do it for 12v systems too. Not so. That's why I could get no response from any 12v lines anywhere on the coach! Just could not understand it. Then I just happened to glance down, and saw the "12V" on the display screen. Duh. Ok, I get it. So I crawled back under the generator, tried again, and yes, I do have power from the cables connecting to the generator. Sort of. The cables themselves have an "O" shaped connector at the end, which slips over a post protruding from the gen. I get voltage on the "O" connectors, part of the wire, but not on the "post" part. So I'm thinking that there's a bad connection between the cable and the gen itself. I'll remove the cables today and wire brush the connections and see if that does it. Is there any treatment I should put on the post to help maintain the connection, like folks use Vaseline on the posts of a car battery?

dave

[wa8yxm]

Where are these solenoids... That is a good question. Let me tell you where I have found them in the past.

First: The ONAN starter solenoid is part of the generator, Just follow the big wire from the starter.. It may be where the 12 volt battery lead connects. Depending on the model of generator.

Now we have the house battery disconnect and isloator solenoids (And the emergency start or aux start one)

IN my coach they hide behind a fuse panel in a box marked INTELLETEC BATTERY CONTROL SYSTEM which is under the hood, driver's side.. NOTE there is a box much like it, no label, in the center (Main chassis fuse box). I point that out only because.. Some day you may blow a fuse.

You might get lucky following the house battery positive line.

Additional... On my coach there is a big whomping thermal self resetting circuit breaker on the house line.. BUT the wiring diagram for the BCC (Battery control center) shows a pair of 30 amp breakers, POST type (Push and hard to reset) in the bottom of the box.

I have seen them in the compartment where the batteries are.

They can be behind the main power panel

In short, most anywhere. Alas, I can tell you they often look a bit like old FORD starter solenoids. A can, metal or plastic, with two LARGE bolts with heavy wires attached and two smaller terminals with smaller wires attached.

IF you operate the main battery disconnect, or have a partner do it, you should be able to hear it CLUNK as power is applied.

[bullydogs1]

I've seen a connector along the rails that once became slightly loose and that kept the generator from starting...

If you can get open compartment or get under it try to trace it back and check connectors..I know.easy to say but not to do..

Are you getting a flashing light when pushing the start switch...?

[dshinnick]

No, battery boost doesn't do it.
I'm not even sure how to check voltage in the battery compartment. Kinda nervous when I know I don't know,what I'm doing!
I'll try looking at some of the solenoids and see if there's anything obvious.

[tropical36]

dshinnick wrote:
Calling all maintenance wizards!

We have an '05 Holiday Rambler Ambassador with an Onan/Cummins QD8000 generator. It is currently dead; no signs of life at all. Last time this happened I was advised to check the power connections at the rear of the unit. I did that just now. There are two, a red and a black. I put my trusty multimeter on them, and nada...nothing.

I assume these leads go back to the battery compartment and tie into the house batteries somehow. Everything back there looks clean and snug, and all other power to the coach is normal. I can run a continuity test and try to trace the cables from the generator to the battery compartment, but I'm not sure if that's the correct strategy. And, I can't find any circuit breaker which might be at fault, other than the one on the generator itself, which I have turned off and back on.

Thoughts?

Thanks-

Dave

Look on the underside of the DC PC fuse board for black plastic encased solenoid relays. Might be a reset button or handle on these that are tripped. Double check for voltage at the house batteries and like has been mentioned, try the aux boost switch as well.

[rgatijnet1]

Will it start while using the "boost" switch on the dash?

[dshinnick]

ok, wa8yxm, very well written answer. I'm on shore power now, but about a week ago we dry camped for two nights and everything worked except the generator. I had, I think, about 11.5Volts in the house batteries. Right now, using my inside power management display, they're showing 13.6, and the chassis batteries are at 13.2. Now, where are these solenoids everyone speaks of? And when I was under the generator yesterday, and I said there was no power at the power connectors on the gen itself, the cables leading to those connectors go up and away toward the rear of the coach, I believe. That's why I thought I should look for a bad connection in the battery compartment, but all seems well there.

Also, when we were enroute to our current park I tried to start the gen several times. Nothing.

[wa8yxm]

There are 3 different battery systems used to start the generator depending on the Motor Home.
Most common: The house batteries
Next: the chassis battery
And on a very few.. A special battery.

Possible issues that can cause your symptoms.

1: Dead battery (Most likely house).
2: Disconnected battery. The generator in many rigs, INCLUDING mine, is on the HOUSE side of the disconnect solenoid.
3: Broken wire or loose connection.

Someone said "The power comes from a solenoid under the hood" TECHNICALLY correct. It does at least on some rigs as it comes in via the disconnect solenoid, (Which is under the hood on my coach) But the starter solenoid is part of the generator assembly. NOT remote.

But if you have the batteries in DISCONNECT, the generator has no power.

Some years ago (2006) I pulled into a Flyin-J and bellied up to the propane pump, Turned off the DISCONNECT (Well technically I engaged the disconnect) to kill all 12 volt power, this also killes all DSI systems on the coach and all flame save the oven and stove which were already off.

Gassed up Then pulled away to park and eat lunch, Pressed the end of the switch to restore 12 volt and .... NOTHING.....

Started the Generator using a jump pack so Id' have 12 volt, then bypassed the solenoid at a later time, downloaded the needed documents and trouble shot the disconnect system.. Found the switch was bad (Remote switch) and fixed it using switch cleaning method #1 (Which almost never works) which is remove all power and cycle it like fifty times.. Worked fine ever since so far.

SO the question is this: DO your 12 volt interior lights work.. IF YES, you have a problem between the solenoid and the generator

IF NO it is the solenoid, batteries or wires between them. Try starting the RV then wait one minute and start the generator.
Then wait one minute and shut off the Main engine.

(Logic: After 1 minute the isolator will have engaged providing engine power to the house, Interior lights should now work.
Then after one mintue of GENERATOR run the transfer switch should have transferred, providing power to the converter. If you shut down the main engine BEFORE the converter engages you will loose power to the generator fuel pump)

[Mr_Mark1]

This may not help the OP but when our generator wouldn't start, I checked our house battery level and they were fine. The engine would start fine and if the engine was running, the generator would start normally.

So, the service shop changed out my two chassis batteries and all was good with the world. What I don't understand is, that the engine would start fine from the chassis batteries but not the generator.

Two years after that I did change our eight house batteries for new AGM batteries. It could be that Monaco set up our systems different on which set of batteries start the generator.

MM.

[Bill_Satellite]

I don't believe he knows what battery(s) connect to the Genset.
When you push the Genset start button, do you hear anything clicking anywhere? Can you trace the cables from the Genset backward to any other connection?

[othertonka]

What does the volt meter read right at the battery itself?? Full charge should be around 12.7 volts. When trouble shooting you should start at the battery itself and go out from there, cables clean and tight, then the disconnect switch, ON? then a good clean ground connection. Well you get the idea. Report back what you find and someone will probably have the answer.

[nelson]

I believe the 12v comes to the gen thru on of the solenoid under the hood