Remote generator start not working, please help

[ShapeShifter]

Problem: Remote generator start switches (dashboard and main control panel) and auto generator start are unable to start or stop the generator.

Motorhome: 2007 Holiday Rambler Endeavor PDQ (Cousin to Monaco Diplomat)

Generator: Onan 8k Quiet Diesel

Wiring Diagrams: 38040925 (DIAGRAM, GENERATOR).pdf and 38051318 (DIAGRAM, AUTO GEN START).pdf

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Sorry for the long post, but I'm really scratching my head on this, and I figure more information is better than not enough.

I'm having a problem with starting and stopping the generator from within the motorhome. Using the switch on the side of the generator itself everything works perfectly. But trying to use one of the switches inside the motorhome, or the automatic generator start, and I get is some stuttering clicking but no action.

Using the above referenced diagrams, I have determined that the wiring between the switches and through connectors C334/P334 and P410 appears to be good. I have also also determined that the remote control functions of the generator are working by going straight to the connector coming out of the side of the generator:

Un-mating that connector, and shorting the wires that correspond to the brown and red wires on the generator side causes the generator to properly start, and shorting the brown and green wires on the generator side causes the generator to properly stop. Measuring the current shows about 70 mA flowing when the wires are shorted.

However, un-mating P411 from the front distribution panel, and shorting the brown and red wires, I only measure about 34 mA, and the stuttering symptoms occur. The same thing happens with the brown and green wires. This makes me think that there is a bad wiring connection between P411 and the above connector on the generator. (I'm guessing it's the brown wire, as that is the one that's common to both the start and stop functions.)

According to the wiring diagrams, the wires from P411 pass through the floor harness and go through P18. From there, it does not show how the wires run to the generator itself. I'm so far unable to locate P18 to check for a bad connection, nor am I able to trace the wires from P411 to the generator.

Does anybody have any suggestions where to find P18, and where the wires from the generator actually tie into the wires indicated on the wiring diagrams?

Before I break down and run new wires directly from P411 to the generator, I appeal to the IRV2 community for guidance. Any advice or help would be greatly appreciated.

[Mike Canter]

So you say that you have ruled out that the remote switch is bad? How did you do that?

[ShapeShifter]

Originally Posted by Mike Canter

So you say that you have ruled out that the remote switch is bad? How did you do that?

A fair question. I determined that two ways: first, by intuition, it would be highly unlikely that BOTH remote switches AND the auto gen start module would all go bad at the same time. None of them can start the generator.

But not being satisfied with that, the real way I determined that the switches and most of the wiring is good was by de-mating various connectors: on the switch side of the connector I was only reading a fraction of an Ohm when the switches are active; while on the generator side shorting out the appropriate control lines causes the stuttering relay clicks that are indicative of the problem.

I'm highly confident that the problem is in the wiring between P411 that connects to the front distribution fuse panel, and the weatherproof connector at the generator shown in the photo above. When shorting signals at the generator plug it works - but when shorting those same signals at P411 it doesn't. The problem must be somewhere between those two points. P18 is somewhere in that path, but I can't find it. I'd like to find it and test it so that I can isolate the problem as either being between P411 and P18, or between P18 and the generator plug, or is it a problem with P18 itself?

But I can't find P18, and I can't figure out how the generator wiring is tied in somewhere in the vicinity of P18.

[jethro]

You gotta be real close. please clarify, have you dissconnected the AGS module by pulling the green terminal block off of the module and attempting a start?

[jethro]

The P-18 connector is used on front engine gas models. Since you have a diesel, this part of the harness won't exist.
Also double check the generator connector by probing the monaco side of the connector wires with a test light that has the clip securely grounded. These generators start by getting a ground signal from the switches or the AGS. Same goes for the STOP, it just sends a ground signal. I can usually start one by probing the START wire with the clip connected to a ground. Try this on the gen plug. If it works, then work your way back. Good Luck.

[chiefdave]

Shapeshifter, Where in the motorhome is the remote located. I had problems until I moved the remote closer to the front of the RV. It had a difficult time sychronizing with the main controll box. I relocated the remote to the front area of the RV.

[ShapeShifter]

Thanks for all the feedback! Let me address them all.

Originally Posted by jethro

You gotta be real close. please clarify, have you dissconnected the AGS module by pulling the green terminal block off of the module and attempting a start?

No, I had not done that... so I just went out there and tried it. Not surprisingly, unplugging the terminal block had no effect on the two inside remote start switches, they behave exactly the same (bad.) Of course, doing that completely disabled the AGS panel, but that's not much of a surprise, is it?

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This gave me some ideas for more tests. At the generator plug, the red (start) and green (stop) wires have about 9 volts on them, and the brown wire is ground. Using an independently grounded wire, and touching it to the red wire starts it right up, then touching it to the green wire stops it. So, th generator is definitely working.

At the AGS module, measuring the red wire shows about 9 volts, and using an independently grounded wire causes the generator to start right up. The green wire reads 0 volts, and grounding that does nothing. So it appears the green wire is open. Connecting the brown ground wire to the red wire causes the generator relays to chatter, so it would appear that the brown wire has a high resistance open.

Repeating the same measurements and tests on P411 at the front bay fuse panel gives the same results as at the AGS module. The red wire is good, the green and brown wires are bad.

So, this latest data pretty much confirms the earlier observations and measurements, just providing a little more detail. There are definitely a couple bad connections between the generator connector and P411/AGS.

Originally Posted by jethro

The P-18 connector is used on front engine gas models. Since you have a diesel, this part of the harness won't exist.
Also double check the generator connector by probing the monaco side of the connector wires with a test light that has the clip securely grounded. These generators start by getting a ground signal from the switches or the AGS. Same goes for the STOP, it just sends a ground signal. I can usually start one by probing the START wire with the clip connected to a ground. Try this on the gen plug. If it works, then work your way back. Good Luck.

LOL, we're definitely on the same wavelength! I didn't see this until I typed in all of the above, looks like I already did the tests you wanted. Grounding the red wire anywhere using a grounded test lead starts the generator. Grounding it with the brown does not. Grounding the green anywhere except at the generator plug does nothing.

So there is no P18 connector. How does the wiring get from P411 to the generator? Is it a straight shot?

Originally Posted by chiefdave

Shapeshifter, Where in the motorhome is the remote located. I had problems until I moved the remote closer to the front of the RV. It had a difficult time sychronizing with the main controll box. I relocated the remote to the front area of the RV.

There is a remote switch on the front dash panel, just inside the entry door. There is another remote switch on the main control panel in the bathroom hallway, about 3/4 of the way in back. The AGS module is all the way in the back in the last compartment on the curb side. The P411 connector is all the way in the front in the first compartment on the street side. The generator is right in front. Hopefully that gives you an idea of the layout.

[ShapeShifter]

One more data point: using some needle probes and piercing the insulation of the wires just on the Monaco side of the weatherproof generator connector pictured in the first post, the generator starts right up when red and brown are shorted, and stops immediately when green and brown are shorted. That convinces me that the connector is mating properly and the problem is elsewhere, in the wiring.

It's now dark out there, and any testing will have to wait until tomorrow morning. As I type this, I've thought of one more area to check: I wonder if the wiring harness has been flexed too much and wires are broken right where the harness folds and bends as the generator is slid in and out? I'll crawl under there in the morning and check for stressed/broken connections where the bends occur.

[ShapeShifter]

And one last detail: this has been an intermittent problem in the past, which has been getting worse until now it is a persistent problem. Also, this morning, the stop function would try to work (sometimes doing nothing, and sometimes chattering during an attempt to prime.) Now it doesn't do anything at all, so it appears to be continuing to go downhill.

I've slid the generator in and out several times today while working on the rig, and the problems seem to be getting worse. Tomorrow, I'm definitely going to take a close look at all the places where that harness flexes while sliding the generator!

[Robi.1014]

Shape,
I don't own such a system, so forgive me when I offer a generic troubleshooting recommendation.

While reading your posts, I homed-in on your observations that when attempting to shut-down (or start?) the genset, you observed chattering.

A chattering relay or solenoid implies that the control-path carrying the amperage that is necessary to energize (or pull) the relay/solenoid to the desired state is lacking the necessary umph. If the chattering is detectable when attempting to control the genset from all of your remote-start/stop locations, then this tells me to look for the common connection shared by these various remote-start/stop devices. You mention as well that this problem has been intermittent. Sounds like a connector that is/was on the verge of failure.

One last thought: Let's assume for the moment that the problem IS NOT a connector. Whatever relay/solenoid that is being activated/deactivated INSIDE the genset may be the very same relay/solenoid that is triggered by the switch located ON the genset. It's possible that this relay (its energizing coil) is starting to fail (age, actually). The switch that is ON the genset can activate/deactivate the relay successfully every time, but the remote switches cannot ... perhaps due to the nominal voltage-loss due to wiring distances of the remotes. To solve THIS problem (if it IS the problem) is to replace the genset's internal relay/solenoid.

Thanks for letting me "rattle on" so........

[ShapeShifter]

Originally Posted by Robi.1014

Shape,
I don't own such a system, so forgive me when I offer a generic troubleshooting recommendation.

All input is appreciated! Thanks for the confirmation, as it sounds like we're thinking mostly along the same lines.

While reading your posts, I homed-in on your observations that when attempting to shut-down (or start?) the genset, you observed chattering.

A chattering relay or solenoid implies that the control-path carrying the amperage that is necessary to energize (or pull) the relay/solenoid to the desired state is lacking the necessary umph.

Precisely my thoughts. When I short out the lines with an ammeter right at the genset, I measure about 70 mA. But when I do the same at a remote switch, it's only about 34 mA peak, bouncing down to zero as the relay chatters. Yes, the relay is not getting enough "oomph."

If the chattering is detectable when attempting to control the genset from all of your remote-start/stop locations, then this tells me to look for the common connection shared by these various remote-start/stop devices. You mention as well that this problem has been intermittent. Sounds like a connector that is/was on the verge of failure.

Again, just what I was thinking. By isolating the system at various places, I think I've narrowed it down as being somewhere between that last P411 connector and the genset. Unfortunately, my wiring diagrams don't match the coach at that point, so I'm at a bit of a disadvantage.

One last thought: Let's assume for the moment that the problem IS NOT a connector. Whatever relay/solenoid that is being activated/deactivated INSIDE the genset may be the very same relay/solenoid that is triggered by the switch located ON the genset. It's possible that this relay (its energizing coil) is starting to fail (age, actually). The switch that is ON the genset can activate/deactivate the relay successfully every time, but the remote switches cannot ... perhaps due to the nominal voltage-loss due to wiring distances of the remotes. To solve THIS problem (if it IS the problem) is to replace the genset's internal relay/solenoid..

I was thinking the same thing early on, but while I could be wrong, I've pretty much convinced myself that the problem is external wiring. With the generator connection unplugged, I can measure poor connections in the coach wiring, and I can reliably control the generator by shorting signal wires right where they exit the generator. Also, using a probe on a local ground, I can reliably start the generator from anywhere using the remote wiring's red start wire. I'm convinced the problem is in the brown ground and green stop wires.

BTW, how did they ever come up with those colors? I can see ground being brown, that's the color of dirt. But everybody knows green is go, and red is stop. Why did they do the opposite?

Thanks for letting me "rattle on" so........

You're welcome, thanks for the input! And thanks for the pun, although it's more of a pulsed chatter, not so much of a rattle!

[ShapeShifter]

Well, the morning got away from me and I didn't have a chance to work on this today. And we're just about to hit the road for a long weekend where I will have no connectivity, so I won't be able to post status or read any suggestions.

I'll continue to work on this over the long weekend, and hopefully I'll have good news to report Sunday evening. In the mean time, if anybody has any other ideas, please post up and I'll see them on Sunday. If I don't get this figured out on my own, I'm going to be plenty frustrated by then and will need all the ideas I can get.

[ShapeShifter]

I found it! There is a P118 after all! It is tucked up above a frame rail, and one of the latches had broken off, allowing the brown and green wires to be intermittantly disconnected. A tywrap around the connector too keep it mated solved the issue.

I have a pic, and will post final details when I get home. I'm posting this from my phone since I stumbled onto a wifi signal. But I just wanted to say it works, and thank everyone for their help.

It was dang cold this morning, and I did not enjoy having to bundle up to start the genny and charge the batteries that were low from running the furnace all night. I won't have to bundle up tomorrow, hooray!

[bullydogs1]

Congrats on finding it!...It's amazing just how stubborn and nuts we RV people can be....Now take out your wallet....and look inside...and smile...