Voltage fluctuation when driving with lights on

[class87]

From: ClydesdaleKevin  (Original Message)
Sent: 6/20/2005 4:11 PM

When driving during the day with the lights off, I get normal voltage at the battery, and there is no fluctucation at my ampmeter dash guage.

When driving at night, however, something strange happens:  I get a very rythmic, very steady, pulsing in my voltage!  This only happens driving with the lights on!  Every 2 or three seconds, my voltmeter will drop just for fraction of a second, and the lights will dim, including the dash lights, also for just a fraction of a second.  Its rythmic, steady, and goes away as soon as I turn the lights off.

Any idea what might be causing this?  I've driven it for hours at night, and it stays constant.  It doesn't get any worse, and doesn't get any better.  Just a steady pulsing in voltage.

Thanks!

Kev and Patti Smith



From: mightybooboo
Sent: 6/20/2005 7:49 PM

You could do  the 'BooBoo' method.New Battery,alternator,voltage regulator,and battery wires(BIG ones)and any grounding cables.Keep the spares.
No finesse here,just results and dependability.

Guess my advice when starter goes bad?If the above hasnt been done already,all of the above plus a starter,heat shields and blanket shielding around starter. LOL!

Hey,it works,just my  philosophy on mechanical things.

BooBoo



From: ClydesdaleKevin
Sent: 6/21/2005 11:23 AM

Thanks BooBoo!

We are putting in a new battery today, and I'll check my connections.  The alternator is relatively new, replaced by a P/O at some point in the Ark's history.  Eventually we'll get all the bugs worked out of her...lol.

Kev



From: denison
Sent: 6/21/2005 12:25 PM

I have been thinking about your problem for a day now. All I can imagine is that something is periodically drawing power, and you only notice it when there is a large demand on the alternator. You could try pulling out fuses, for the heater, wipers, whatever, and see if the symptoms change. If you only use one battery, try disconnecting it from any of the coach "load".
The mopar volt. regulators can go sort-of-bad after years, and will allow some discharge, followed by a larger than necessary charge, and then repeat -- but its not too periodic, sort of random, and likely to be doing its little stunt over minutes, not 2 or 3 seconds.
I suppose I would add a wire, between the case of the VR and the case/bracket of the alternator, and see if that cleared it up.
My voltmeter is apparently reading the voltage between the metal of the instrument panel and the junction where the alternator feeds into the system at the starter relay. I get a wide variation in readings ( a couple of volts) , just from the heater fan running, or the turn signals or wipers being on - though I have measured the voltage at the battery terminals, and you dont see more than a fraction of a volt change there. Reads about 14.6 if the RV has been running for a while, though on the dashboard it might say 14 or 15 or 16, depending on whether the headlamps and heater fan are both on.
And does the voltage still cycle every few seconds, if you have the headlamps and everything on - but with the engine stopped? Does your RV have the "intermittent wiper" function?
Keep us informed. This sounds like a really arcane mystery!



From: ClydesdaleKevin
Sent: 6/21/2005 4:52 PM

Hmmmmmmmmmm...I love a good arcane mystery...lol. 

I think the ultimate solution to guage fluctuation would be to add aftermarket guages for water temp, oil pressure, tach, volts, and of course tranny temp.  I'll pick up the guages as soon as we pass somewhere that sells them (thus the only drawback to NOT having a "toad"...lol).

I don't have intermittent wipers...they are either on or off.  The fluctuation is the same if I am parked with the lights on, or driving.  Its a mystery!  If its not cleared up by the August Jam in PA, maybe ya'll can help me troubleshoot it!  Until then, I'll keep working on it.

Kev



From: steelman_ny
Sent: 6/23/2005 9:00 AM

when i run my lights the gages go crazy also, but if i turn the light switch counter clockwise and dim or turn off the dash lights the gages go back to normal. my brother-in-law told me it is just the reostat switch in the lights. 



From: Slantsixness
Sent: 6/23/2005 9:59 AM

Kev,
First,
Do you have a Phillips converter? and do you run the Ark with two batteries, or one? The old Philips converters (long silver or brown one with slots along the sides and the drop down door in the rear) These units have a really REALLY poor charge sensing system that is basically a 12V relay that operates at a threshold of about 12.2 volts. With the vehicle running, the converter 12V relay should be "off". However when current drain is large (lights on at night) this relay can cut in and out intermittently to charge the coach battery while in "dual" mode. What basically you see is the ammeter will dip like the turn signal is on at a rate of about once every two seconds.
Short answer to this problem? replace the antiquated converter with a newer style with the charge wizard. You can change it in about a half an hour, and a 50Amp (more than adequate for most motorhomes) will cost about $140 with the charge wizard. Do not use a conveter with less than a 30 amp rating, or you will experience even more lighting problems when the coach is parked.

Secondly,
Replace the mopar gauge regulator with a 78M05 regulator and get away from the old bi-metallic strip gauge regulator. These strip regulators (the little 3 pin tin can on the back of your dash) have been unreliable for years. However, if you don't use the 78M05 regulator, carry a spare tin can gauge regulator, and replace yours. This is most likely the cause of gauge fluctuation, inaccuracy and erratic behaviour, and it can and will cause a voltage "flicker" to show up in the ammeter and dash lights too.

Lastly,
Check the Grounding to the dash panel. More often than you'd expect the ground wires become corroded or detached and cause the only grounding of the dash to be achieved through the panel dimmer and parking lights! This is what I believe is happening in SteelmanNY's case above. It's not a bad light switch or panel rheostat! Check it to make sure. Also headlight ground wires can cause a similar but less spectacular dash "freakout".

Tom 



From: Winnielover4078
Sent: 6/23/2005 7:35 PM

I've had a couple of chrysler cars that have done that in the past, turns out it was the voltage regulator both times. It acted up worse when there was a load on it like the headlights being on. Just a guess, but at least its a cheap fix....kenny



From: ClydesdaleKevin
Sent: 6/25/2005 7:27 PM

First, I don't think my old Phillips Converter has anything to do with it.  It only comes into play when on shore power, or when the generator is running.  The guages react the same whether on shore power, generator, or just plain driving.

Secondly, the guages act the same whether the dimmer switch is set to light the dash or not.

Thirdly, its still happening, after cleaning my terminals and checking my grounds and getting a new battery.

Any ideas?

Kev



From: Liv42dayOK
Sent: 1/31/2006 1:32 AM

From: ClydesdaleKevin
Sent: 8/9/2005 12:53 AM

Driving to Connecticut tonight from the NECWJ, we had the same arcane voltage fluctuation. 

Anyone have any idea where the heck the voltage regulator is on this thing?  That sounds like the most plausible thing to try replacing first.  My rig is an "orphan" Futura, not a Winnie.  So, what I need is not only the location to where YOUR regulator is, but more importantly, which wires from the alternator do I need to trace and track to find mine?

Thanks!

Kev


From: denison
Sent: 8/9/2005 11:27 AM

I believe on all the Dodge chassis, the V.R. is mounted on a metal plate attached to the top of the transmisson bell housing at the back of the motor. It has 2 wires going into its one connector, and its case should be well grounded. One of the wires is red, and gets 12v when the ignition is on. The other is light green and runs to one of the two small field coil (or exciter coil) terminals on the alt. The other field coil terminal on the alt has a red wire, that gets 12 volts whenever the ignition is on. The v.r. regulates by switching the green wire. If you measure the voltage across the field coil with an analog voltmeter, you should see an averaged voltage that represents how much the alternator is being asked to put out. It will increase/decrease in reponse to the turn signals or flashers, for example. It think it is pulse-width modulation, but I never put an oscilloscope on it to really check.
the other 2 alternator connections are a ground wire, and the heavy wire that takes the output back to the system, going through the ammeter on the way.



From: daved27c
Sent: 8/10/2005 12:08 AM

Kev;

The vr is mounted on the drivers side. As Denison stated it is atteched to the bell housing on the tranny. The vr is a metal box roughly 3 inches X 6 inches. It has a triangular shaped plug in it. To get to it, turn the wheels of the Ark all the way to the right. Get yourself into the second to the worse spot to get to on one of these. ( The worse spot being under the dash). The vr will be above the frame, just below the Ign relay. Once you see where it is, it is possible to change it from the top, but you have to do it by feel.

Dave



From: ClydesdaleKevin
Sent: 8/10/2005 11:37 PM

Thanks guys!!!

I'm working on the power steering hoses tomorrow...

My NEXT task will be to find the darn voltage regulator...obviously, I'll look at the bell housing first, and use all your advice to trace the wires back from the alternator if its not there.  Once I find it, I'm going to replace it and see if it clears up my problem.

My NEXT task after that is to figure out why my starter won't start all the time...I had to start it with a screw driver jumped across the terminals twice on the way to Connecticut coming from the NECWJ!  In looking at it carefully, I noticed a lot of heavy green scale (copper corrosion) on the connections at the starter.  I also noticed that the heat sheild between the exhaust pipe and the starter is non-existant!  I'm going to clean up the connections and add a heat sheild Denison-style (lol), and see if it solves the problem...

THEN the next task...to figure out why the darn marker lights (which are all brand new and properly grounded to the aluminum skin) decided to quit working.  My tail running lights also went boobs-up on me.  I'm going to run a ground strap from the aluminum skin to the frame and see if that works...but I don't think that's the problem:  My porch light is grounded to the skin and works great, and the brake lights/signals still work, and they share a common ground to the aluminum skin with the rear running lights in the tail-light assembly.  I guess I'll just have to check the voltage, and look for broken/loose connections...maybe even run new wires.

After that?  Find the evil gnomes that are hiding in my rig and breaking things, and deal with them Mafia-style...lmao.

Always something, eh?

Kev



From: denison
Sent: 8/11/2005 9:35 AM

I would advise making up a test light. A small bulb with 2 long wires attached, having alligator clips at the ends. So you can have the light visible inside the RV, one alligator clip on the frame, the other on the smaller wire leading to the starter, or to the pin on the starter relay that runs to the neutral/safety switch (which should 12 volts on it whenever you are in neutral or park and turn the ign. key on. Then when the starter wont operate, you can begin to isolate that failure. 



From: jbmhotmail
Sent: 8/12/2005 6:55 PM

Kevin

Check out this website and see if it would apply to your fluctuation problem.

http://www.imperialclub.com/Repair/Electrical/voltage.htm

Jerry



From: ClydesdaleKevin
Sent: 8/14/2005 4:47 PM

Thanks Jerry!  I bookmarked that page.  Just as soon as I figure out what style voltage regulator I have, and once I find the elusive thing, I'll replace it.  If its mechanical, this site is invaluable to finding the right electronic replacement!  If its electronic, then I'll replace it and see what happens.  I was just bragging to my wife how Connecticut RARELY gets extremely hot and humid, and we arrived here right in the middle of a heat wave...lmao.  I'm waiting for the weather to get a tad cooler before I do more troubleshooting.  In the meantime, we are holed up in the AC watching movies.  It was a HUNDRED degrees yesterday in East Killingly, CT, with 99 percent humidity!  Its a record!  Thank the Winnie gods for AC!

Kev   



From: ClydesdaleKevin
Sent: 9/3/2005 9:58 PM

When replacing my starter relay, I found the voltage regulator!  Its right under the starter relay, on the same metal plate to which the relay is mounted.  It was on the upper driver's side of the engine, almost at the bellhousing.

Anyhow, I replaced it with a new one...and my voltage is still fluctuating with the lights on!  I also replaced every corroded fuse and cleaned out the fuse block...still the same.

I have a sneaking suspicion that this problem is directly related to the mysterious cessation of my upper marker lights and rear markers.  As this only occurs when the lights are on, and since every other light works, including the front markers, I'm really starting to think that the problem is a short somewhere with the malfunctioning marker lights.  A short might cause the wierd load and voltage fluctuation I'm getting when the lights are on...

I'll let y'all know what happens when I troubleshoot the lights...for now?  We are at the King Richard's Faire, in Carver, MA, for the Labor Day Weekend...This is a lot of fun!

Kev



From: denison
Sent: 9/4/2005 6:49 PM

Its interesting they picked on a King Richard for the fair. I wonder if they had a specific -Richard- in mind. There were only 3 real ones, none of which I would have chosen as a role model for anything. Perhaps they meant one of Shakespeares two plays of that name?



From: ClydesdaleKevin
Sent: 9/8/2005 11:55 PM

I'm guessing, Dave, since these faires are all fun and fantasy, that they chose King Richard from the Robin Hood legends...lol.

Kev



From: ClydesdaleKevin
Sent: 12/6/2005 6:48 PM

PROBLEM SOLVED!!!  While troubleshooting the lack of running lights at Tom's house, we discovered that, when I had installed the awning brackets, my dummass screwed right into the wires, grounding them out!  Apparently I only grazed the wires, because they would sometimes be shorted, and sometimes open...thus the fluctuation.  The short caused all the lights to go out except the headlights and front marker lights, which were dim.  The alternator, struggling against the extreme current draw, was making the dash meter dance and make that "d'oing" sound.  It took us a while to isolate the problem today, but we did it!  Thanks Tom!!!  Anyhow, the lights are ON, all of them, and there is no longer any fluctuation.  It was a simple fix.  Tomorrow we mount the higher auxihilary rear marker/turn/brake lights in conjuction with the original ones.  A police officer told me that my bike rack and cover was obscuring my lights, and since there is no other place to put the bikes, we are just going to add higher lights.

Kev



From: LJ-TJ
Sent: 12/6/2005 7:07 PM

All fixes are easy in hindsight. Isn't that like twenty twenty after the fact. T.J.



From: DampDude007
Sent: 12/6/2005 7:18 PM

Holy crapola,are you sure you want to give her away,it sounds like you are fixing everything,are you sure you want the "Beaver"??
Dude



From: ClydesdaleKevin
Sent: 12/7/2005 1:02 AM

Gotta love Beaver!...lmfao...Umm, yeah...lol.  Actually, I'd love to keep the Ark, but fulltiming it in a 25 footer, which is effectively only about 19 feet long because the cockpit area is HUGE, with my wife, a cat, and two German Sheps is getting very crowded.  If we buy a bigger rig, no matter which one we buy, the Ark will go to a very good home.

Kev