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-   -   Univolt. Still can't solve 12 volt lighting! (https://www.airforums.com/forums/f37/univolt-still-cant-solve-12-volt-lighting-10941.html)

chasgould 04-23-2004 06:59 AM

Univolt. Still can't solve 12 volt lighting!
 
Hi Guys,
I hope that someone on this list can help me. I have a 1976 Argosy 28 footer, remarkably original condition with very little after market modifications. The engine battery system works fine. The Univolt hums when plugged in, and appears to be putting out around 12 to 16 volts DC for charging.
The sytem is set up so that the interior lights are supposed to run off of the coach battery in normal mode, or will run off of the engine battery when the key is turned to the accessory position. This would also allow the Univolt to recharge the engine battery (as well as the coach battery) when the key is in the accessory position.
When plugged into a city 110 outlet, all of the interior 110 outlets work fine, and the univolt appears to put out proper charging voltage, but none of the 12 volt lights will work off of the coach battery. They will work off of the engine battery when the key is turned to the accessory position.
There appears to be 12.9 to 13.5 volts at the coach battery terminals indicating that the Univolt is producing the voltage to charge the battery, and this voltage drops (or disappears if the terminals are not on the battery) when the Univolt is unplugged, so I do feel as though the Univolt is operating properly.
But the coach battery appears to be disconnected from the entire lighting system, or the lighting system appears to be disconnected from the Univolt and from the coach battery, as no 12 Volt lights or accessories will work without thekey in the accessory position, which brings the engine batteyr online.
I have checked the coach battery polarity, and although correct, there is a small weird curiosity. A volt meter from the NEGATIVE terminal of the coach battery to a vehicle ground reads 12 Volts. Obviously, the Negative terminal should have continuity with the ground, and not produce 12 Volts. I learned of this factor when I accidentally touched the NEGATIVE battery post to the vehicle ground and got some sparks! I would have expected this with the POSITIVE terminal, but not the NEGATIVE terminal.
So could the battery have switched polarity, somehow. Or could the interior lights be disconnected from the Univolt system or coach battery? Any other ideas?
I have solved almost all of the other problems, but this one has me completely stumped!
Also, can the air-conditioner be recharged, now that freon has been taken off of the market. Should I look for a trenchcoated gray market freon dealer in the back alleys?
Finally, what is the deal with the 454 exhaust manifold gaskets. Is there a permanant fix. Do you recommend installing TWO gaskets, or planeing the heads before resinstallation?
Thanks for all of your help.
Chas

smily 04-23-2004 07:14 AM

Just a couple of answers
 
The Freon is still available, expensive and only liscensed tech can purchase.
If you live close Mexico, you can buy it there. Or grey trench coat dealer is in order, still expensive.

The manifolds, Nope, no fix other than aftermarket manifolds or headers that do not crack or warp. Yes you machine manifolds and install new gaskets if the manifolds are not damaged. You can also add deflectors to force more air onto manifolds, this is a GM retrofit but you can do it yourself. You can add hoses to direct air onto your manifolds.

As for electrical problems, I am not familiar with the older models.

Smily

74Argosy24MH 04-23-2004 07:43 AM

Quote:

Originally Posted by chasgould
Finally, what is the deal with the 454 exhaust manifold gaskets. Is there a permanant fix. Do you recommend installing TWO gaskets, or planeing the heads before resinstallation?

Are they leaking now? If so do as Smily says if your mating surfaces are bad. 2 gaskets will be counter productive, more insulation and what you really want is the heads and manifolds to be fairly equal in temperature. Use new locking fasteners, torque and retorque after a few heat cool cycles. Let your engine run at idle for 3-5 minutes before shutting it down, especially if it has been running hard. A lot of heat builds up after shut down, this is when problems start.

John

overlander63 04-23-2004 07:46 AM

A volt meter from the NEGATIVE terminal of the coach battery to a vehicle ground reads 12 Volts
You have a bad ground from the coach batteries to the coach body, or a blown negative fuse to the Univolt. Repair as necessary. R134a conversion costs about the same as a charge of R-12, with the benefit that in the future you can buy refills from the parts store, and do it yourself.
Terry

chasgould 04-23-2004 08:25 AM

Univolt problems
 
Thanks to John, Smiley and everyone else for your help. You guys are great.
Hey John, the large Negative fuse in the front of the engine compartment, behind the service door, seems to be fine, as does the Positive fuse, and all of the fuses at the Univolt.
Should I just run a new test lead from the negative coach battery to a coach ground somewhere, just to test and see if that cures anything?
I am in Massachsuetts. Does anyone know where I can go to convert the freon to the new coolant, and roughly how much it will cost.
Thanks again for all of the help.
Chas

Chuck 04-23-2004 08:50 AM

Where in MA are you?

I bet Marty's USRV (the local airstream dealer) could take care of you.

chasgould 04-23-2004 08:52 AM

I am in Newton, Masachusetts, near Boston. I prefer to go west from here, rather than north or south, but anywhere close will work.
Thanks
Chas

Chuck 04-23-2004 09:08 AM

Quote:

Originally Posted by chasgould
I am in Newton, Masachusetts, near Boston. I prefer to go west from here, rather than north or south, but anywhere close will work.
Thanks
Chas

Well, Marty's is probably about 45 minutes or so south. I don't think there's much here around the city in terms of RV dealers...slim picken's in general. most seem to be down on the south shore, for whatever reason. there's nothing up my way. a couple in Southern NH. I think others are out west, but beyond the Worcester area.

technically, any hvac tech could do what you want, but I don't know if I'd want them up on the curved roof of my airstream. and they might not want to do it, either.

thenewkid64 04-23-2004 09:37 AM

IF you can find a HVAC guy to do it you will be many $$ ahead of a RV place when it come to the roof AC. All they want to do is R&R it. Sell you a new one. IF it is an Armstrong, and working, but not cold enough I would search for someone to get it fixed. If it is a Coleman I would R&R it. The Coleman's do not last the way the Armstrong's do.

The Armstrong's use normal AC parts.

uwe 04-23-2004 10:53 AM

Chasgould,
Are you talking engine A/C or rooftop A/C?
The engine A/C ( dash air) is easily converted. It takes a complete evac, then a special A/C lubricant along with different fittings. This makes it ready to receive R134. Some vehicles requuire chages of temperature switches and/or compressor cutout switches.
They used to make a big deal out of it, and make you change compressors and driers, hoses etc., as well as every single o-ring in the system. That was hype to make more money on the regulation on the manufacturer's part.
I had 3 cars converted, and it was less than $ 100.00 each time, including temp and compressor switches with different values. ( 2 Mercedes cars, and a Dodge van with dual A/C) I have since sold the Dodge, but the 2 others still work great.
The rooftop a/c is another story. I imagine i too, could be easily converted to R134 if it indeed uses R12.

chasgould 04-23-2004 02:31 PM

Hi Terry,
Thanks for the input on my Univolt/coach battery problem. Give that man a Kupie doll. He had the correct answer. It was a bad ground to the coach battery, and running an ancillary ground did solve the problem in that the 12 volt accessories now all work as long as the unit is lugged into 110 volt city power. Should the 12 volt lights and accessories run off of the coach battery without 110 volt city power. If so, is ther a switch to activate that?
Thanks,
Chas

overlander63 04-23-2004 07:29 PM

Quote:

Originally Posted by chasgould
Hi Terry,
Should the 12 volt lights and accessories run off of the coach battery without 110 volt city power. If so, is ther a switch to activate that?
Thanks,
Chas

Sounds like you also have a bad connection from the batteries to the coaches' 12v system. You now have lights when plugged into shore power, that takes away a lot of guess work. Have you checked your batteries?
It sounds like you are close to taming the monster, keep checking, there is only so much wire between the battery and the electrical distribution panel.
Terry

jjonesnc 04-23-2004 07:48 PM

Chas,
Due to the age of you coach I would highly reccomend replacing the reciever/dryer on your dash ac when you have the retrofit done. I have done Motorhomes of the same age as yours, some needed entirely new systems and some were ok but few. ALL of them had reciever/dryers that were as heavy as a brick
-Jason

chasgould 04-24-2004 05:40 AM

Quote:

Originally Posted by argosy20
Sounds like you also have a bad connection from the batteries to the coaches' 12v system. You now have lights when plugged into shore power, that takes away a lot of guess work. Have you checked your batteries?
It sounds like you are close to taming the monster, keep checking, there is only so much wire between the battery and the electrical distribution panel.
Terry


I guess that you mean that the 12 volt stuff should work, even when not plugged into 110 power. So, are you suggesting that I runanother test lead from the positive terminal of the coach battery to the positive outlet of the UNIVOLT, or to somewhere on the coach wiring? But where? If it were not hooked to the UNIVOLT< I would not get 14 volts at the batter terminals, so I suspect that you are correct, that it needs to be tied into the coach somewhere. Would a bad ammeter at the control panel cause this lack of connections?
I am taming this beast, but I prefer to move on to other problems! Thanks for the help.
Chas

chasgould 04-24-2004 05:41 AM

Quote:

Originally Posted by jjonesnc
Chas,
Due to the age of you coach I would highly reccomend replacing the reciever/dryer on your dash ac when you have the retrofit done. I have done Motorhomes of the same age as yours, some needed entirely new systems and some were ok but few. ALL of them had reciever/dryers that were as heavy as a brick
-Jason

This makes sense, except I am dealing with the rooftop coach air-conditioner. I haven't gotten to the truck air yet.
Chas

overlander63 04-25-2004 08:24 AM

Quote:

Originally Posted by chasgould
I guess that you mean that the 12 volt stuff should work, even when not plugged into 110 power. So, are you suggesting that I runanother test lead from the positive terminal of the coach battery to the positive outlet of the UNIVOLT, or to somewhere on the coach wiring? Chas

Close. Hook a jumper wire from the + terminal of your coach battery to the + side of the buss bar in your fuse panel. If everything now works, you know you have a problem in the feed wire from the battery. Replace as necessary.
Good luck.
Terry

overlander63 04-25-2004 08:26 AM

Quote:

Originally Posted by chasgould
This makes sense, except I am dealing with the rooftop coach air-conditioner. I haven't gotten to the truck air yet.
Chas

If it is low on freon, find someone that is a household A/C guy, he can repair it with little problem, as these units are little more than a slightly oversized room A/C in your house.
Terry

chasgould 04-29-2004 07:08 PM

Taming the electrical monster!
 
Thanks for your patience guys. I am getting this electrical beast tamed, but slowly. I now have 12 volt lights and appliances when plugged into 110 power, or when running the onboard generator.
I don't have 12 volt lights from the coach batteries, and I no longer have 12 volt lights from the engine battery when the key is turned to accessory, which I did have before.
I did run a new ground wire from the negative coach battery terminal to the chassis ground, which solved the 12 volt power when plugged into 110 volts, but also caused me to lose the 12 volt power when the ignition key was on accessory.
I suspect that someone has added a solonoid or relay to act as a battery isolator or to prevent battery draw down when not in use. There were articles and drawings in the manual and paperwork indicating this addition. When I open the access door up front, there is a rather large, rounded body solonoid which the battery terminals go to, and a much smaller rectangular modern relay or solonoid as well. There is also a 20 amp fusable link, but it appears good with continuity across the posts.
Are one or both of these solonoids stock parts or were they added by a previous owner. How do I test them? How do I bypass them to test the system without them? How would they work if working properly. Would the relay close as soon as a load were detected, or would there have to be a hidden switch that I can't find, or was it intended not to allow the 12 volt lights and appliances to work unless the ignition key were on accessory, which seems ridiculous, as it would tend to kill both batteries instead of keeping the engine battery isolated out of the system?
Any help would be appreciated.
Thanks,
Chas

torin knorr 05-12-2004 09:56 AM

The univolt beast
 
Chas

I have a 1985 270 A/S MH. I am having the exact problems with my 12 voly system that you have. No 12 volt off the house battery, 120 & generator work fine. I will be resolved to having it looked at my a local shop if I come to a dead end. I haven't checked my neg. ground, or the ned fuse( not sure where to look) found everything else. During my hunt I did find a switch @ the glove compartment the allows one to bypass the starter battery when it is low, it is connected to the solinod. Learned something new.
I really want to solve this thing as bad as you.

torin knorr
1985 270 w/ banks power exhaust

chasgould 05-12-2004 10:55 AM

Univolt beast
 
Eurika!!! I finally solved the Univolt/12 volt accessory problem. Pay attention, Torin, as I bet this is the same problem with your Argosy.
There are two large fuses under the engine access bay, where you check the radiator and batteries etc. They shoukd be in the center of the access panel right in front of you as you open it. You will see the negative out in the open, and the positive is under a black plastic cover with a single stud and nut to secure the cover. Although these fuses may be fine, the fuse holders tend to corrode, and do not make a good connection to the fuse body, so that even though you will have continuity across the fuse, you will not across the fuse holder. The fuse msut be removed, and the bracket or fuse holder, sanded or scraped clean to make a good contact with the fuse body. I found that both my positive and negative were both culprits, and required cleaning.
A good way to test this problem is to turn on the 12 volt lights which you can see from the front of the truck while accessing the service panel, and watch the lights while you rotate the fuses in their holders, or run a temporary jumper wire across the fuse holder bracket. Be sure to scratch it into the metal as the outside of this bracket is also corroded.
Finally, on your rig, that isolation switch or the solonoid may also be the culprit, but my money is on these fuse holders, as the solonoids are usually quite reliable. The previous owner may have added that switch and solonoid to prevent the coach battery from running down when not in use. It should not have anything to do with the bypass of the engine battery. It either disengages the coach battery to prevent run down when not in use, or it links both batteries in series for engine starts or jumps when the engine battery is weak. Please let me know if this helps you on your problems.
Thanks,
Chas


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