FS2020

I think I solved the problem of the coach batteries not charging when on shore AC: The coach battery disconnect relay feeds into a ShortStop 40A circuit breaker. I just realized that there's a little black button that resets the Shortstop breaker. I pushed the reset and it started charging the coach batteries. I feel kinda dense for not noticing the Shortstop reset, but it is not marked and there are no directions. I'm an engineer but I have no experience with RV electrical systems. I basically had to figure out the entire battery disconnect and charging system. I have spent at least 50 hours on this problem. I took the RV to two RV repair shops around Pittsburgh and neither one of them would even try to diagnose the problem. They said they repair RV's but electrical systems are too complicated for them. I must agree. I tried to attach a photo of the Shortstop breaker for others, but it won't let me. A window pops up and asks for URL to the image. How do I attach a photo to my post? To see if the problem of parasitic drain had been solved, I disconnected shore AC and measured 12.58 V on the coach batteries. 18 hours later the coach batteries were at 12.49 V. Now that the batteries are being charged by shore AC, the 40A AC-DC converter should easily cover the parasitic load when on shore AC. We're going to sell this RV and buy a newer, smaller one -- and I'll be sure to buy a shop manual with it!!! Thanks everyone! Frank

Each rocker switch is supposed to receive 12V. Then the switch sends + or - 12V to the disconnect relays to open/close the relay. The chassis rocker switch is receiving 12V. The coach rocker switch is receiving only 2.5V. I just connected the 12V supply from the chassis switch to the coach switch, and the coach switch now works. But I think you're right, I could have a short somewhere in the wiring to the coach rocker switch.

Thanks to your expert advice, I have the battery disconnect relays working now. But power from the coach batteries is not being delivered to inside the RV. The chassis power works fine and the engine starts. The power from the coach disconnect relay goes through a "short stop" breaker that is labeled "Short Stop 24V D33 4OA." (I tried to attach a photo, but it asks for a URL. When I tried a URL is gave an error?) I jumped it with my multimeter and 1.5 A is flowing through it. That's only 18W at 12V. Is that too much for a normal drain from the coach with everything off? In any case, I'm going to replace it and see what happens. Thanks, Frank

Update: I took apart the Power Distribution Panel and verified that the Intellitec Battery Disconnect Relays are working. Inside the door of the RV are two rocker switches that open/close the Battery Disconnect Relays. The switch for the coach batteries was only receiving about 2 V. It needs 12V to open/close the disconnect relays. So I jumped the 12V feed from the chassis switch into the coach switch, and it now the coach disconnect relay works. Also, the coach batteries are no longer being drained by a parasitic load. Some progress, slowly. Thanks, Frank

Thanks so much for the service manual Rich! I had been trying to find it for a long time. I started it again and let it run for awhile and the engine speed gradually slowed down to normal. It ran for about 20 minutes then shut down. I'm hoping I've brought it back to life, with good advice from this forum. Thanks, Frank

OK, I got the generator to start! But it sounds like it's running at full speed so I shut it down after a few seconds. I'm thinking the linkage that controls the carb is stuck? Any other thoughts? I agree completely with Kay: I need to run the generator on a regular basis to keep the brushes and carb clean. Thanks everyone! Frank

I flushed the carb with concentrated fuel injector cleaner and let it sit for 24 hours. I've verified that it's getting gas and the fuel pump works, it's getting spark, it's getting 12.7 V from the batteries. I tried several times a day for several days to get it to start. So I've given up and scheduled an appt with Cummins Onan near Pittsburgh. It's a one hour drive each way. Last year it cost me $150 to fix this problem. I will post what the Cummins Onan tech's say was the problem. Thanks for trying to help! Frank

Thanks Rich, I just made a mixture of 8 oz of fuel injector cleaner (enough for 20 gallons of gas) and 8 oz of gas. I fed it through the fuel intake line. So the carb bowl is full of concentrated fuel injector cleaner and hopefully it will dissolve the gum. I will let it sit for a few hours and try it again. Thought I would try that before taking the carb off. That also verified that the fuel pump is working. Will let you know the results. Frank

I added carb cleaner to the gas and sprayed carb cleaner into the carb, then let it sit for a few hours. I removed the air filter and sprayed starter fluid into the air intake. It sounds like it's firing when I hold the start button down, but as soon as I release the start button, it shuts down. I've tried to start it at least ten times, hoping the clog in the carb would clear out, but it hasn't (if it's a clogged carb). What next? Do I need to pull off the carb and soak it? I'll verify I'm getting gas and spark first. Thanks, Frank

Rich, Good call. You are right, even though the fuse is in the chassis fuse box, it is causing a 1.5A drain on the coach batteries. The Intellitec disconnect relay for the coach batteries is not working. I have ordered a new relay and new switch panel. Helps to have a second set of eyes! Thanks, Frank

Potable water tank. The fill port is at the rear corner of the RV, driver's side. Thanks, Frank

I have a 1998 Thor Four Winds Windsport RV. It has a water holding tank near the rear of the RV. I can't find the valve to drain the holding tank. Anyone know where I might find the drain valve? Thanks! Frank

I have an Onan 4.8kw gasoline generator in my RV, Model 5BGEFA26100N, SN H973723191. It cranks and sounds like it's firing when I hold the crank button down, but when I release the button, the generator shuts down. Last spring I took it to an Onan/Cummins shop and they got it working. They said "the brushes needed cleaning" or something like that. We didn't use the RV last year, so the generator sat without being used for a year. Now it's doing the same thing, cranks and sounds like it firing when the start button is held down, but stops as soon as I release the start button. Thanks for any suggestions! Frank

The fuse labeled "Body Builder Accessory Feed (Run Only)" is in the chassis fuse box under the dash. So the fuse is for a chassis accessory. I think Ford called it's electrical chassis system "Body Builder" for RV's. I cannot find anything that stops working when I start the RV and pull out the Body Builder Access fuse. The engine runs. The lights, AC, windshield wipers all work. What other chassis accessory could there be that is only turned on when the engine is running? Thanks, Frank

There is an Intellic relay based battery disconnect system. Just inside the door are two rocker switches that activate battery disconnect relays. Is that what you're referring to?

A bit more info about my coach batteries not being charged when I'm plugged into shore AC. I took the DC output leads off of my PowerSource PC 50 converter, and connected the leads to a high current 12V battery charger. But still no power reached the coach batteries. So the link between the AC-to-DC converter and the coach batteries is broken somewhere... Thanks, Frank

YES! Thanks to the advice from this forum, I found the parasitic load that was draining my coach batteries! I removed the negative cable from the coach batteries, then connected my multimeter between the negative cable and the negative terminal of a coach battery. It showed that 1.5 A was being drained from the coach batteries. I then measured the voltage drop across each fuse. One fuse had a 200 mV drop across it!. I removed that fuse, and that completely stopped the parasitic current drain from the coach batteries. The fuse is labeled "Body Builder Access Feed (run only)" Does anyone know what that is??? Now I just need to get the coach batteries to be charged when I'm connected to shore AC. When connected to shore AC, no charging power is delivered to the coach batteries. vielen veilen Danke!!! Frank

All, My RV is a 1998 Thor Four Winds Windsport. The metal sticker under the dash says the vehicle ID number is 3FCMF53G4VJA22935 and the Model Number is WA04698. I had AutoZone test my batteries today. All are at 12.5 V and producing 550 CCA. They are rated at 875 CCA. So they are somewhat weakened. I am pretty sure there is a large parasitic load. The parasitic load drained the batteries a few times. That's probably why they are weakened. I need to find the parasitic load before I replace the batteries. This evening I will put a volt meter across each fuse to try to detect the parasitic load. I have a good multimeter that should detect small millivolt drops across a fuse. I think i should also replace the Powersource PC50 converter. It's output is rated at 12VDC at up to 50A. This converter is no longer made. Can anyone suggest a good replacement? Thanks to everyone for the excellent advice! Frank

Rich, There are more fuses and breakers in this RV than I can shake a stick at! There's a fuse box under the rear bed, a fuse box under the dash, a fuse box inside the power dist box, and two more high amp breaker boxes in the engine compartment. I think I need to systematically remove fuses and see if the batteries stop draining, until I isolate the load that's draining the batteries. In addition, I need to understand why the coach batteries are not being charged. The Intellic disconnect switches are not always working, so I'll start by replacing them. I've helped to solve some national level crises, but this one has me pulling my hair out! Frank

Wolfe10, I have one 12V auto battery for the engine/chassis and two 12V deep cycle batteries connected in parallel for the coach. I will get the specs for you later (it's cold and dark in Pittsburgh now), but they're typical 12V chassis and coach batteries. I am going to do some tests to try to find the large load that's draining the coach batteries. I will charge the coach batteries, then remove fuses from certain 12V circuits, and then connect the batteries. When the coach batteries stop draining, that should track down the load. However, I am still faced with the problem that my coach batteries are not being charged when shore AC is connected. Thanks, Frank

Rich, The photo is of the power dist box that has a disconnect relay for the coach batteries and a disconnect relay for the chassis battery. Power from the batteries enters through the two copper bars in the center (see red arrows pointing up). The cables labled S and I are from the rocker switches inside the RV that activate the disconnect relays. When activated, the relays connect coach and chassis power to the RV. The voltage in and out of each relay was 12.3V, the same with and without shore power. I'm still trying to figure out why the coach batteries are not being charged by shore AC. That might solve the problem, even if there's a large load on the coach batteries. Thanks, Frank

Wolfe10, Thanks again for helping me troubleshoot this! All of the batteries are new. They've been on a float charger and were at 13.3 V today before I connected them to the RV two hours ago. Now the batteries are at 12.4 V. Seems like something is drawing current from them. And they are not being recharged by shore AC. I will pull out the batteries and test them, but I doubt that they are bad. if they are bad, somethnig made a new battery go back very quickly. I'm starting to think that something is broken (a disconnect relay, heater element, etc) and is shorting to ground and draining the coach batteries. But no fuses are blown. I remain bemused. Thanks, Frank

Thanks for the thoughts Wolfe10 I measured voltage across both chassis and coach batteries with the engine off, and both are at 13.3 V. I started the engine and let it idle at ~900 rpm. The voltage across the chassis battery was 14.9 V. The voltage across the coach batteries dropped to 12.1 V. I'm perplexed. Why would the coach batteries drop from 13.3 V to 12.1 V when I start the engine? It's almost like a load is applied to the coach batteries when the engine is started. When the engine is off and I'm connected to shore power, there is no power applied to the coach batteries. Sorry about my confusion of invert/convert. The Powersource PC50 takes 120VAC and converts to 12VDC. Any thoughts appreciated. Frank

Thanks Rich The Inverter is a PowerSource PC50 producing up to 50A at 12VDC. The alternator is charging the chassis battery just fine, and I've verified the output of the alternator. But I don't think the coach batteries are charged by the alternator... is that correct? Does anyone know if the Battery Disconnect system also disconnects the coach batteries from the PowerSource charger? I've had problems with the Battery Disconnect for the coach batteries. Thanks! Frank

I have a 1999 Four Winds Windsport RV. The coach batteries are not being charged when I'm connected to shore power. I've verified this by measuring the voltage at the battery terminals when on shore power. There is no change in voltage when I connect to shore power. I have checked the 120VAC to 12VDC inverter that I assume is supposed to charge the coach batteries. It produces 13.5 VDC (with no load) and powers all of the 12V components in the RV. The RV uses an Intellitec battery disconnect system. Inside the door are two switches to disconnect the chassis and coach batteries (see photo below). Also below photos of the Intellic disconnect relays inside the power distribution box that's in the engine compartment. I'm an mechanical engineer and I have spent a huge amount of time trying to fix this. So I will be immensely grateful if anyone has suggestions. Best regards, Frank