Occasional warning light?

[romtim]

Hello.
Our motorhome is a 38foot Monaco Diplomat 2000.
We used to have no warnings of any kind and now I'm dealing with a couple of simultaneous issues. I'll do my best to explain what's going on.

1) The first warning was a low coolant that went on and turned off within a minute when I first attached a car hauler behind. Since then that low coolant warning is appearing and disappearing without any particular cause (not because of going uphill or downhill). Sometimes it happens on a flat highway and stays on for 5 minutes, sometimes it happens when parking somewhere and just appears for a couple of seconds and disappears. I checked the level of the coolant, it's not low. There are no apparent leaks anywhere. Can't find where the sensor is, so can't really clean it. I am constantly checking the engine temperature while driving and it's never too high, and this low coolant thing happens for like 0.1% of total driving time. So if I drive for 10 hours, it'd be on for maybe 1 minute on average.

I am not so worried about this one, because the temperature is always fine and it usually doesn't stay on (the record was 30 minutes, with the 2nd place being somewhere around 5 minutes). Am I right to not worry too much about this low coolant thing? Maybe some sensor glitches or a rusty contact? (checked everything I could, and everything seems attached fine).

2) Warning. Now, this is just a red warning light, that SOMETIMES appears when you start the RV. It doesn't seem connected to anything. Sometimes when I turn the key and wait for "WAIT TO START" to turn off, it will appear there (maybe once in every 7 times I turn on the RV). Sometimes it doesn't appear then but appears as soon as I actually start the engine. Also about once in every 7 times or so. When it happens, all I have to do is to turn off the engine and start the RV again and it usually goes away (90% of the time, or if it persists, and I restart again - it will go away for sure).

Again, I'm not so worried about this since its so inconsistent, but is there an easy/cheap way to read what is it catching on some of those starts? Is it something to be concerned about, or not really since it always goes away?

3) Alt charge warning & Tachometer dropping to 0. This happened out of the blue while driving on the highway - started showing alt charge warning and showing 0 on the tachometer instead of the usual 1700-1900. And it was turning on/off, bringing back power to the tachometer. For some reason, it stopped doing that when I turned on the A/C on the dashboard. A few weeks later I was digging around close to the alternator and a wire popped out really easily. I have replaced that connection 2 weeks ago and since then I have not seen any more alt charge/tachometer issues even without the a/c on.

4) Once, the RV just failed to start after turning it off while fueling up at a gas station. Just nothing happened when I turned the key to start the engine. I thought it was a low battery for some reason and have disconnected everything, waited for 10 minutes and it worked after that. Now I don't know what happened then, but it hasn't repeated since, and that also happened PRIOR to me fixing that wire connection from 3). Maybe fixed now? Not sure. However, when I turn on the headlamps, on the dash the battery drops about 1.5v, and gains them back when i turn them off. Same thing when I turn on the A/C. The prior owner said that's what they've experienced for years and he blames the old dashboard for showing it not correctly, and hasn't seen it as an issue. I am guessing that IF it is an issue, it can be both bad batteries (I accidentally had them dead for a week or two). Or, bad alternator. But so far so good these last few weeks after fixing that connection.



So, to sum up. The only thing that keeps popping up randomly is a WARNING light, and occasionally I see a LOW COOLANT light as well. Everything else has not been happening since I replaced the wire connection.

Any suggestions on how to deal with all this? I know that if I go to some service center and just tell them everything I just wrote out for you, it will cost me an awful lot of money for them to hunt down these issues while they are probably not so serious. However I am also tired of worrying about these things popping up and ruining my mood, so is there something I overlooked, something I can do myself?

Thanks for reading!

[steve52]

Step one is to get someone who knows what they are doing--i.e. an actual mechanic, not the counter guy at Auto Zone--to hook it to a real scanner and read any stored codes, as well as look at (and interpret) the other info that the ECM parses and saves.

[RVSSNAKE]

I have a similar issue with my Warning light.

You might look at my thread link below and see if you can glean some info from that.

That is if the pasted link works.


http://www.irv2.com/forums/f115/warn...ht-420062.html

[8.3Oilbuner]

Good morning Romtim; Well, nothing drives you CRAZY like finding the solutions to what you have posted. Some of us have had the same problems. If you read RVSSNAKE response to your post, you will read my post response to his question about the warning light. When our coaches get to be the age they are, corrosion can affect grounds and poorly crimped terminals over the years depending on what kind of climate you live in and weather you store the coach outside. On the low coolant light, you need to find the low coolant sensor. On a 2000 Diplomat, I am not sure what tank design tank you have. It could be just the connector on the sensor, or the sensor that is immersed in the coolant need cleaning. I think you have the alternator problem under control. If you are reading the voltage for the chassis battery on the dash gauge, it is not accurate. I have the same problem on my Windsor. Monaco did not use heavy enough wire for grounds and this causes the gauges to not be accurate. Also the grounding will find it's way through other gauges and cause inaccurate readings. If you want accuracy, you need to get a ScanD reader that plugs into the diagnostic port under the dash and gets the information right from the engine ECM. This device also has code reader capabilities. I have the Silver Leaf System and now could not live without it. The only dash gauges I read now are the tach. and spedo.
As for the starting problem. I had this happen on my 01 Windsor. It happened to be the starter solenoid wire was loose on the starter solenoid. It was tightened and no more problems. This is one of the smaller wires on the starter solenoid that sits on top of the starter. I think you might have a lot of electrical connection problems. I would get some good contact cleaner and start making your rounds on areas that are giving you grief. Let us know what you find and if a fix did the job. Sorry for the long post to answer some of your questions. Good luck!

[barmcd]

You need to pull the code with a code reader or have a competent shop pull the codes. You probably have several active.

I'm pretty sure there is a sensor on the plastic coolant tank. Check out this thread:

http://www.irv2.com/forums/f115/low-...rts-86528.html

That warning light can be for a variety of things. One of the most common is a failing TPS. The symptom you descrive is exactly what happened to me. Eventually, it'll get to the point where you don't get any response from the accelerator pedal. When that happens you can still modulate the throttle with the cruise control buttons. It's an inexpensive part and easy to replace.

The tach signal comes from the alternator, you loss of tach signal and alt warning indicates you have an issue with the alternator itself or the wiring going to it.

[mlh2013]

Originally Posted by barmcd

You need to pull the code with a code reader or have a competent shop pull the codes. You probably have several active.

I'm pretty sure there is a sensor on the plastic coolant tank. Check out this thread:

http://www.irv2.com/forums/f115/low-...rts-86528.html

That warning light can be for a variety of things. One of the most common is a failing TPS. The symptom you descrive is exactly what happened to me. Eventually, it'll get to the point where you don't get any response from the accelerator pedal. When that happens you can still modulate the throttle with the cruise control buttons. It's an inexpensive part and easy to replace.

The tach signal comes from the alternator, you loss of tach signal and alt warning indicates you have an issue with the alternator itself or the wiring going to it.

Dennis you are correct about the tach being tied to the alternator. I had a 99 diplomat, when my alternator started going out my tach would be very erratic. Replaced alternator and it solved tach problem too

[romtim]

Originally Posted by steve52

Step one is to get someone who knows what they are doing--i.e. an actual mechanic, not the counter guy at Auto Zone--to hook it to a real scanner and read any stored codes, as well as look at (and interpret) the other info that the ECM parses and saves.

Ok, so there is typically no way to read the codes yourself?

[romtim]

Originally Posted by RVSSNAKE

I have a similar issue with my Warning light.

You might look at my thread link below and see if you can glean some info from that.

That is if the pasted link works.


http://www.irv2.com/forums/f115/warn...ht-420062.html

Thank you, I will take a look at that thread now!

[romtim]

Originally Posted by 8.3Oilbuner

Good morning Romtim; Well, nothing drives you CRAZY like finding the solutions to what you have posted. Some of us have had the same problems. If you read RVSSNAKE response to your post, you will read my post response to his question about the warning light. When our coaches get to be the age they are, corrosion can affect grounds and poorly crimped terminals over the years depending on what kind of climate you live in and weather you store the coach outside. On the low coolant light, you need to find the low coolant sensor. On a 2000 Diplomat, I am not sure what tank design tank you have. It could be just the connector on the sensor, or the sensor that is immersed in the coolant need cleaning. I think you have the alternator problem under control. If you are reading the voltage for the chassis battery on the dash gauge, it is not accurate. I have the same problem on my Windsor. Monaco did not use heavy enough wire for grounds and this causes the gauges to not be accurate. Also the grounding will find it's way through other gauges and cause inaccurate readings. If you want accuracy, you need to get a ScanD reader that plugs into the diagnostic port under the dash and gets the information right from the engine ECM. This device also has code reader capabilities. I have the Silver Leaf System and now could not live without it. The only dash gauges I read now are the tach. and spedo.
As for the starting problem. I had this happen on my 01 Windsor. It happened to be the starter solenoid wire was loose on the starter solenoid. It was tightened and no more problems. This is one of the smaller wires on the starter solenoid that sits on top of the starter. I think you might have a lot of electrical connection problems. I would get some good contact cleaner and start making your rounds on areas that are giving you grief. Let us know what you find and if a fix did the job. Sorry for the long post to answer some of your questions. Good luck!

Thank you for your detailed reply! Any idea where I can get the ScanD reader? a quick google search didn't return nothing...

That's an interesting take on the gauges, makes sense why they're so jumpy in that case! I will look into the Silver Leaf System, sounds like its very useful!

I will then get the contact cleaner. Yeah, for me also it didn't sound like something is seriously wrong, but it's just a pain to locate where are the connection issues coming from .

The tachometer/alt charge issue still didn't appear. The low coolant issue happens usually on slow speeds when moving up and down parking lots and whatnot, when starting or finishing the drive. The warning still appears occasionally while starting the motorhome. The motorhome had no trouble starting no more.

Going to either get some reader somewhere or go to a mechanic who can read error codes. And going to look at the coolant tank again, as well as the contacts running to around the engine area and spray everything clean.

[romtim]

Originally Posted by barmcd

You need to pull the code with a code reader or have a competent shop pull the codes. You probably have several active.

I'm pretty sure there is a sensor on the plastic coolant tank. Check out this thread:

http://www.irv2.com/forums/f115/low-...rts-86528.html

That warning light can be for a variety of things. One of the most common is a failing TPS. The symptom you descrive is exactly what happened to me. Eventually, it'll get to the point where you don't get any response from the accelerator pedal. When that happens you can still modulate the throttle with the cruise control buttons. It's an inexpensive part and easy to replace.

The tach signal comes from the alternator, you loss of tach signal and alt warning indicates you have an issue with the alternator itself or the wiring going to it.

Thanks! I'll look into the coolant tank once more. Any recomendations on a code reader? No more tachometer/alt charge issues, so I guess I fixed the wiring.

[RVSSNAKE]

If you go to Advanced Auto Parts online store, I got a 25% off code from the top of the page to apply at purchase.

Mine was 119.99 with code plus tax no shipping.

It is Scanguage D.

[BCam]

I think that the advice of going to a qualified mechanic is the best. Even if you buy a scanner, you're going to need expert help in deciphering what needs to be done. If you just want to know what codes are showing/stored, go to the auto parts store and have them scan it.

Since you have multiple, and intermittent, things going on, I think you might have a problem with the warning system as a whole rather than a simultaneous failure of multiple sensors or multiple problems.

[barmcd]

Originally Posted by romtim

Ok, so there is typically no way to read the codes yourself?

You need a tool capable of reading the communication codes used by Cummins.

About the cheapest unit available is the Scangauge D at about $140.

https://www.pplmotorhomes.com/parts/...onitor_92-1538

[BCam]

So, let's say you buy or borrow a code reader and it gives you one or more codes. Now what do you do about it? That's where the mechanic comes in, so why not just go to a mechanic in the first place? Once you have the code you're going to need the knowledge necessary to interpret it and determine how to fix the problem. Here's a link to a list of codes, fyi:

https://repairpal.com/obd-ii-code-chart

I'm not against having a ScanGuage or the like (I bought one myself) since it gives you a lot of real-time info on how you're engines running, etc. Being able to read a code is also nice since it will tell you more than a "check engine" light, not so much in terms of telling you how to fix a fault but in terms of knowing if the fault is something serious that you need to take care of immediately or if it can wait.