House batteries not charging when coach running

Thanks for the help guys. here is where I'm at now. After more trouble shooting with a voltage meter and trying a ford solenoid I had setting around I still have nothing. I assumed the ford solenoid would work for testing proposes and used it. Here is what I'm getting with the engine running: the solenoid has 3 lugs, 2 large and 1 small (actually 4). The small lug is only getting 7 volts?? The large lug attached to the chassis batteries has 14V and the lug going to the house batteries has nothing. Assuming the ford solenoid is good, why am I not getting anything to cross over the terminals? Is 7V sufficient on the small terminal? I checked out the alternator too. As far as I could see, there is one larger, app 6 gauge, wire coming off the alternator and two smaller wires. I could not get a reading off the 6 ga wire for some reason, but am assuming that is what is charging the chassis batteries and assume it's ok. Of the two smaller wires one is reading 13.8V and the other is reading 7V. Does that sound right?

If I can not get this figured out before the weekend, can I jump the house and chassis batteries together for the ride there and disconnect them when I get to where I'm going? Could this cause anything to short out, especially the alternator?

Thanks again guys

luckydog3550 wrote:
there is also a 3 post solenoid up front in the generator compartment. The small lug is receiving 14V while the engine is running but the two larger posts only have 12.5V. The wire on the top lug comes directly from the house batteries.

Each large lug goes to a battery bank-- one to house, one to chassis.

Not sure I understand how the signal terminal connected to the house battery (sounds like an odd signal source to me-- I would have expected it to be an "ignition hot" source and usually off the chassis battery) could have 14 VDC and yet the large lug to the house battery could have 12.5 VDC.

If neither large lug is receiving alternator output (14 VDC)with the engine at high idle, the problem may be in your alternator or between the alternator and solenoid.

luckydog3550 wrote:
there is also a 3 post solenoid up front in the generator compartment. The small lug is receiving 14V while the engine is running but the two larger posts only have 12.5V. The wire on the top lug comes directly from the house batteries.

The one up front is the IGNITION side components of the dash systems
The one in the rear is your charge solenoid. NO, you cannot use just any solenoid. You must get a solenoid that is for CONTINIOUS duty. Just ask for one that is for continous duty. For instance, a lot of people think a Ford solenoid will work, but a Ford starter solenoid is for momentary duty, not continous. NAPA would be a good place to get one as well as Tiffin. Doug

there is also a 3 post solenoid up front in the generator compartment. The small lug is receiving 14V while the engine is running but the two larger posts only have 12.5V. The wire on the top lug comes directly from the house batteries.

Will any 3 post solenoid work?

dougrainer wrote:
1997, the odds are in the drivers side rear between the frame rail and the Chassis battery box. Is the chassis battery box in the drivers side rear compsrtment? Tiffin just used a standard 3 post solenoid. 2 large posts and 1 small post from the Ignition side 12 volt power. The solenoid was grounded to the chassis frame. Until you fix it, just run the genset in transit to keep the coach batteries up. Doug

Thank you, I believe I found it. Chassis battery box is located on the passenger side. The solenoid is located on the side of the battery box. It is getting 14V to the top lug with the coach running but the bottom only has 12.5V (same as coach batteries are putting out). Is this my problem? Thanks again

Not sure about your '97 but on our coach the charge solenoid is in the rear PS compartment. You might want to go over to the Tiffin RV Network and join the "forum" there. Lots of very knowledgeable people to help you there.

Actually, the splitter is either a DIODE-BASED BATTERY ISOLATOR or SOLENOID-BASED BATTERY ISOLATOR.

Tiffin can tell you which you have and were it is located, or you can follow the large-gauge wire from the alternator B+ terminal and it will go to the isolator.

1997, the odds are in the drivers side rear between the frame rail and the Chassis battery box. Is the chassis battery box in the drivers side rear compsrtment? Tiffin just used a standard 3 post solenoid. 2 large posts and 1 small post from the Ignition side 12 volt power. The solenoid was grounded to the chassis frame. Until you fix it, just run the genset in transit to keep the coach batteries up. Doug

Thanks. I any idea on how to find the splitter?