Community Forums

hshiner · 07-01-2016, 07:57 AM

We were having alternator problems, had the alternator replaced. All voltage readings look fine. The only problem is the alternator light on the dash stays on.
Can anyone shed some light to help me.
Thanks

2003 Monico Windsor 370HP
Full timing eegugqaaraaaRAaRA
Summerfield, FL.
Arafat
Toad: Volvo very gevS
RVsEayfy

mel s · 07-01-2016, 08:18 AM

Quote:

Originally Posted by hshiner

We were having alternator problems, had the alternator replaced. All voltage readings look fine. The only problem is the alternator light on the dash stays on.
Can anyone shed some light to help me.
Thanks

Methinks whoever sold and installed the replacement alternator is reasonable for that problem.
Have you asked them to complete the job you paid them to do?
Mel
'96 Safari

jacwjames · 07-01-2016, 08:13 PM

Check the DuVac fuse in the passenger side rear run bay, it may be blown. A recent post had the same symptoms and this was the problem.

2003Mountain · 07-01-2016, 08:32 PM

We were at a Campground that had just "rewired" several 30 Amp sites before we arrived special for us as we were part of a sizeable Rally. They got it wrong and our EMS would not let us get any power. We had to run a generator all night to get the A/C working. It was about 90 out and the Campground said the Power Company was in a "Brownout". Well, I worked for that Power Company and they would kill the power before they went to a serious Brownout condition.

So if you have a problem with the electrical source the EMS should not allow you to get any power.

TOM

Jeff753 · 07-01-2016, 08:38 PM

Quote:

Originally Posted by hshiner

We were having alternator problems, had the alternator replaced. All voltage readings look fine. The only problem is the alternator light on the dash stays on.
Can anyone shed some light to help me.
Thanks

2003 Monico Windsor 370HP
Full timing eegugqaaraaaRAaRA
Summerfield, FL.
Arafat
Toad: Volvo very gevS
RVsEayfy

I believe there is an alternator fail relay that may be bad. If you find one (mine is in the low current box rear drivers side) you can swap it with another relay (marking wires and terminals) and see if it fixes it.

Jeff
2001 Dynasty Regent tag axle
Cummins 350 8.3 ISC
2012 Jeep Grand Cherokee Overland
FMCA U60 Task Force Chairman

windsorbill · 07-01-2016, 09:49 PM

Hshiner

Start your main engine. Alt light comes on. Try turning on your headlights. Does alt light stay on?

dpinvidic · 07-01-2016, 10:11 PM

When you picked it up, what did they tell you about the light?

Is the new alt. an exact match for the old one.

Dan

YC1 · 07-02-2016, 04:18 AM

IF you are still connected to shoreline or in some cases, running the generator, you can get the light.

bborc · 07-02-2016, 04:05 PM

What YC1 says is right. Sometimes if I start the engine with the mh pluged in to shore power the light will come on. I think it is in an overcharge conidition

hshiner · 07-03-2016, 06:54 AM

First I want to thank everyone for your help, overwhelming to your saport. The repair ahi finally figured it out in 10 hrs. (Not happy)
I finally left the shop as I lost all confidence in there ability to trouble shoot the issues. I left with the Warning Light still on. All codes are clear and there appears to be no problems at the moment. But still need to find out why the light is on.
On this note can anyone out there shed some light on this new problem. I will trouble shoot this on my own.
Thank You
2003 Monico Windsor
400 ISL

Dr4Film · 07-03-2016, 07:55 AM

First off it sounds like you had the alternator replaced instead of rebuilt. Not the preferred method as these alternators are not off-the-shelf items.

If the shop did NOT replace it with the EXACT same brand and model then that is why your Alt Fail light is still activated on your dash or if they used the same brand and model then they mis-wired the alternator.

There is an Alt Fail relay located in your FRB that receives a signal from your alternator to turn off the dash light when your alternator is working correctly.

I have had the same problem for many miles now but I just haven't had the time to search out why. I usually keep an eyeball on the SilverLeaf VMSpc display to monitor the voltage that the alternator is putting out.

I have posted what one person had sent to me for my troubleshooting once I do get into searching out the problem.

"Looking at the Monaco chassis schematics, the alternator fail light goes on when the alternator fail relay sees a 12 volt signal from one of the terminals on the back of the alternator. It should go out if the fuse in that line is pulled. If the light goes out, then the alternator is truly sending a "fail" signal, and may need repair. If it stays on, then your probem is somewhere in the relay circuitry or in the line to the warning light bulb. That bulb wiill be lit when that line is shorted to ground. The alternator fail relay will connect that line to ground when it sees a 12 volt signal from the alternator."

Here is another message that I received from the same person.

If there is a tightly controlled pull in voltage for that 42006 Hamsar relay, I can't find any mention of it. The Hamsar site merely touts that it is water and dust resistant, and low delay for action. My Monaco chassis electrical schematic just shows a relay with the 87 terminal as not connected. When the alternator fail signal comes from the alternator, that relay connects the alt fail dash bulb to ground. That same line is also used for the tachometer.

"Looking at if from the other end, I tried to find a circuit diagram for the Duvac regulator; no luck!. There have been multiple references that the alternator in Monacos are "different than a standard truck alternator." It appears that the major difference is that Duvac alternators have the field current drawn directly from the chassis batteries. It also appears that the Duvac line connection furnishes a reference voltage that allows the alternator to bump up the output voltage to compensate for any diode isolator drop. A standard truck alternator gets its reference voltage from the B+ terminal which is very close to the actual battery voltage. Truck batteries will be mounted under the hood and near the engine, so there is little voltage drop."

Hopefully some of this information will help you in your troubleshooting.

Dr4Film ----- Richard

hshiner · 07-03-2016, 08:11 AM

Alternator was rebuilt, did find the relay that was causing the light to stay on, removed and replaced light out. What I am left with is the warning light is still on. All codes are clear.

2003 Monico Windsor 370HP
Full timing eegugqaaraaaRAaRA
Summerfield, FL.
Arafat
Toad: Volvo very gevS
RVsEayfy

jacwjames · 07-03-2016, 09:00 AM

Did you check the DuVac fuse (id you have one) in the passenger side rear run bay???

Dr4Film · 07-03-2016, 09:49 AM

Quote:

Originally Posted by hshiner

Alternator was rebuilt, did find the relay that was causing the light to stay on, removed and replaced light out. What I am left with is the warning light is still on. All codes are clear.

Your post is not so clear or understandable!

OK, you removed and replaced the Alt Fail Relay and your Alt Fail light went out. So which warning light are you referring to?

I don't understand what codes were you trying to read and where you are trying to read them.

I only have one warning light on my dash, the red Alt Fail light.

Dr4Film ----- Richard