rockynob Report post Posted April 6, 2012 My coach is a National Sea Breeze -- 2007 model year. All batteries were removed for the winter. After reinstallation of fully charged batteries, I am unable to get any electrical power to the chassis. All coach systems are working properly. Both thermal circuit breakers near the batteries are working properly. Any ideas??? Share this post Link to post Share on other sites
Briarhopper Report post Posted April 6, 2012 WIthout knowing more about you particular system, the chassis ground is the first thing that comes to mind, or a disconnect. More info would be helpful. Maybe describe how the coach and chassis batteries are set up. Just to confirm, you have no chassis lights, no starter cranking, etc.??? Share this post Link to post Share on other sites
rockynob Report post Posted April 6, 2012 Thanks for the response. I have a single 12v chassis battery and a series pair of 6v golf cart batteries for the coach. Both the chassis battery and the coach battery set have thermal circuit breakers mounted in the battery compartment. These cb's both are operating properly when hand tripped and reset. There is no power to the chassis -- no chassis lights such as head lights and 4-way flashers and no engine cranking. Is there any more specific information that I can provide? Share this post Link to post Share on other sites
wolfe10 Report post Posted April 6, 2012 Are the things that aren't working only those things that work with the ignition key in the ON position or do they include things that normally work when the key is not in the ignition? Share this post Link to post Share on other sites
rockynob Report post Posted April 7, 2012 The two things I can think of that normally work without the ignition switch on are the headlights and the four-way flashers. These are not working. In addition, nothing that requires the ignition switch on are working. Share this post Link to post Share on other sites
Briarhopper Report post Posted April 7, 2012 You mentioned fully charged batteries. Have you verifed with a digital multimeter that the chassis battery is indeed fully charged? Should read 12.6 volts more or less depending on temperature. Share this post Link to post Share on other sites
rockynob Report post Posted April 7, 2012 Yes, it is verified by voltage measurement as fully charged. Also it does charge when the motorhome is plugged in to shore power. Also, the emergency start/battery boost switch does not help. Share this post Link to post Share on other sites
Briarhopper Report post Posted April 7, 2012 It still seems like a ground problem or disconnect that is open and considering the young age of the coach, I would not think a ground would have loosened. Do you have manuals for coach and chassis to double check there are no additional battery disconnects of either manual or automatic? Share this post Link to post Share on other sites
rockynob Report post Posted April 7, 2012 I checked resistance from the chassis battery negative terminal to the engine and found virtually no resistance (<<1 ohm). Also I checked voltage from the engine to the chassis battery negative terminal and it was zero. This should indicate good ground integrity. The heavy wire connected to the starter motor also showed no voltage, which is a real mystery since all heavy wires I can find in the battery area and the DC panel are hot. I have checked all fuses and circuit breakers I can find with no problems found. The wires are difficult to trace physically since they are all in large bundles and go in and out of accessibility. But the only next step I can think of is to start unbundling the wiring bundles to try to do a physical trace. I hate to do this because it looks like a major undertaking. If anyone knows of any disconnect from the battery to the starter motor and the rest of the chassis functions, it would be much appreciated. Don Share this post Link to post Share on other sites
campcop Report post Posted April 7, 2012 Sometimes there is a relay before the starter and would be in the power distribution box in the engine compartment. Only other thing I can think of is there is a fusible link burnt between the battery and the power distribution box. Any signs of rodent damage? Share this post Link to post Share on other sites
Briarhopper Report post Posted April 7, 2012 It has been awhile since I played with starters, so my info may be dated. I also imagine a newer vehicle may have electronics that could be an issue either as part of the problem or sensitive to testing. The starters I am familiar with have either a solenoid mounted on the starter or mounted remotely and in either case the hot from the battery attaches to the solenoid. If your system has a remote solenoid, then the cable at the starter will not be hot until you turn the ignition key. The low resistance batt- to engine seems to indicate a ground. Voltage test from engine to batt- would not show voltage if you have an open condition on the positive side even with no ground. Testing for voltage from batt+ to chassis and/or engine would check the ground. No reading = no ground. Reading close to battery voltage should indicate a good enough ground to at least light a bulb. (Somebody confirm I stated this correctly.) If the ground is good, it would seem to indicate an open condition on the positive side. As campcop mentioned any chance of rodents? By DC panel are you referring to a chassis fuse block that has power right now on the hot side? Which chassis and engine do you have? When you hooked up the chassis battery, have any unusual sparking, clicks or pops?? Share this post Link to post Share on other sites
BillO Report post Posted April 8, 2012 I'll offer up a couple of possibilities from my own experience with a different brand MH. Is there a master switch somewhere (most likey around a DC fuse panel) that may have been inadvertently turned off or flipped itself off without power? My coach has separate master switches for house and chassis circuits that once got turned off by a well-meaning friend while setting up at a campground, causing a good deal of hook-up confusion. Does the coach have a built-in security system? That may open chassis circuits when power is interupted and need to be reset with the remote. Share this post Link to post Share on other sites
rockynob Report post Posted April 8, 2012 Stuart, thanks for your interest. The chassis is a Ford F53 (gas) with the Ford V10 engine. There is a solenoid mounted on the starter motor -- I have not been able to find any others. The voltage from the chassis battery positive to the chassis/engine is 12.7v or 13.6v with the charger connected. I am confident there are no rodent issues -- under coach is very clean and there is no evidence of rodent activity. The DC panel I referred to is the coach-mounted panel. The chassis fuse block has no power to the normally hot side. There was some sparking when I attached the ground cable to the chassis battery. Don Share this post Link to post Share on other sites
Briarhopper Report post Posted April 8, 2012 Hey, there’s nothing like an intriguing mystery to keep the gray matter flexible. Interesting that there was a spark when you hooked up the ground cable which would indicate a flow of current, but no current anywhere now. The 12.7 volts also indicates no current draw on the battery. Have you or can you verify voltage is getting past the thermal circuit breaker? Share this post Link to post Share on other sites
dewat Report post Posted April 9, 2012 I am probably the least qualified to answer here, but I have been reading stories where the relays for the chassis can, and will fail in a open or closed mode (Ford F53's). The symptoms that you are describing sound like what happens when the chassis and house switches at the entry door are turned off, which sounds like a failed relay once the chassis switch is turned on. Again, I am only taking a shot in the dark based on other things I have read, but that is what it sounds like. Share this post Link to post Share on other sites
rockynob Report post Posted April 9, 2012 Well, thanks to all, but I sit here red-faced. I ran a separate cable from the chassis battery positive all the way up to the starter motor, and everything had power. So I was sure there was an open somewhere in the cable. I opened cable bundles and traced the cable from the starter motor all the way back to the battery box and when pulling it, it was loose -- not connected. It turns out that there are two cables that connect to the positive terminal of the chassis battery. One goes to the thermal circuit breaker and the other directly to the starter motor. The cable to the starter motor had slipped through the hole in the battery box and was out of sight (and out of mind). I hooked it up and everything was fine. A couple of observations: 1. The thermal circuit breaker does not disconnect the battery from the chassis -- only from the DC control panel. 2. There is a splice in both the positive and negative chassis battery cables about mid way from the battery box to the engine. These splices could be a source of resistance due to corrosion over time. Thanks again for the help. Don Share this post Link to post Share on other sites
Briarhopper Report post Posted April 9, 2012 Great News. Been there, done that on the red-facededness. Seems I do more of those as time goes on. On the bright side, we all learned a few things and it was a cheap fix, which is the best kind. Share this post Link to post Share on other sites
