I’m looking for ideas on a generating problem we’re having with our 12V alternator system on our 2000 Allure. Cummins ISC engine.

In January 2008, while driving from New Orleans to Livingston, TX I noticed the dashboard gauge indicated less than 12V. Whenever this gauge drops below 12V I keep an eye on things and it usually comes back up within a short time. This time it continued to go down. When the gauge dropped more I flipped switches while watching the gauge to see if I had one accessory item that was causing an abnormal drain on the system. Nothing changed.

We were about 50 miles from our destination and it was getting late in the day so I decided to go for it. While driving we called the Rainbows End RV Park (our destination) to see if they could recommend a repair shop to go to before we checked in at the park. They told us of one about 3 miles past the park. By the time we arrived at the shop it was about 4 or 5 PM and the gauge was below 10V and the transmission was shifting out of control and the PacBrake valve was opening and closing every few seconds even though the PacBrake switch was off. We pulled in and the engine quit. Would not start. The owner of the shop informed me that he does not work on diesel pushers but helped me find a diesel mechanic locally. The diesel mechanic and I agreed to get the engine running and I would head for the RV park and he would come to see me the next day. We boost charged my batteries and the engine started.

The next morning I checked everything I could with my volt/ohm meter. The alternator was putting out 14V as per specs. Everything seemed to be OK. When the diesel guy arrived he checked out as much as he could and everything was OK. Cha-ching $120 road service charge.

Everything was fine until about 6 weeks later. The same thing happened at Big Bend National Park. But this time I was a little more aware of things and I started the generator. It worked fine for several hours until we arrived at out destination. The next morning I checked things again and the alternator was putting out 0, nothing, nada. I found someone to rebuild the alternator in Alpine, TX and everything seemed to be OK. Cah-ching another $120.

3 weeks later, on our way home to Indiana, the whole thing started over again. We made it to our destination for the night in Sunnydale, AL. Thanks to the generator again. I spent an entire day checking things (I’m neither a mechanic nor an electrical expert) but I was able to determine that the alternator was not putting out anything. In a state of confusion and frustration I ordered a new alternator from Country Coach after talking to the tech there. Cha-ching $500 ($350 plus $150 next day shipping). I checked out the alternator after my installation and she was putting out 14V.

About 50 miles from home a few days later the whole scene repeated it’s self again. Now I’m suspicious that neither of the alternators were at fault. But I have not checked them since we have got home. I talked to John at Country Coach and he suggested that it could be the ignition switch relay that is not exciting the alternator properly or possibly one of the two oil pressure switchs on the engine which is supposed to activate the charging system when the engine oil pressure is 15psi or higher.

I would like to know if any of you have experienced this type of problem and what you had to do to fix it. Also if you guys have any ideas or suggestions. I plan on working on it this coming week.

Thanks.

First thing I would do is to make sure all connections, especially the ground are clean and tight. If they are and you still have the issue, check for exciter voltage coming into the altenator. If no voltage check the mentioned relay and oil pressure switch. You may have to verify that you have good oil pressure late in the run when it seems to be causeing you the problem. Good luck & kepp us posted.

Thank you for the quick response, Mike.

What do I do to check out the ignition relay? First I have to find it - but I'm not sure what to do when I do find it.

I'm pretty sure I should simply disconnect the wires from the pressure switch and then start the engine. When the oil pressure rises the switch should either close or open. Correct?

Oh by the way, I have a very good set of electrical diagrams for almost all of the on-board systems. Three gigantic three ring binders full. Thanks Country Coach. They have been a lifesaver several times over the past few years.

The wiring diagrams should tell you where the relay is located. THe wiring itself should be labeled so you can identify what your looking for. THe schematics should also show you if the contacts on the pressure switch is closed or open with pressure. Good luck and let us know what you find.

Check the relay that is in the doghouse in front of the passenger seat as well. You may want to do a search on the Country Coach Yahoo Group site as well. There are a number of posts with a similar problem.

Just a quickie update . . .

I still have not found the cause of my problem. Mostly due to other obligations here at the homestead. I have to take my wife to radiation treatments every day nowadays and it's very difficult to get out there to work on the 40 ft. money pit.

I have a wiring situation that I'm not sure how to deal with. My wiring diagrams show #34A 12ga. yellow wire from the ignition solenoid to the alternator exciter terminal. With the ignition key in the ON position I have 13V (+/-) at the solenoid terminal but 0V at the alternator exciter terminal. I suspect a break in the wire somewhere in the harness. But here's another issue with this wire . . . at the exciter terminal I have two 16ga. brown wires and no 12ga. yellow wire. Experience tells me that brown wires are sometimes in-line fusible links. I cannot imagine why a fusible link would be in this line. I cannot trace the two brown wires back towards the front of the coach because they get lost in a gigantic wiring harness cover where there are many, many wires in there. Access to this harness is awful.

Also, at the 15psi oil pressure switch my wiring diagram shows only one (12ga. I think) blue wire going from this switch on the engine block to the battery booster solenoid. In reality, I have a waterproof snap plug on the connection at the pressure switch that has three tiny black wires in it. Again, this tiny wiring gets lost in a wiring haeness.

What a mess. In my current home situation I cannot afford to go to a shop to have it worked on. Sometimes life just keeps on coming at you doesn't it!

I must say, though, that John the tech. at Country Coach has been very good to work with on the telephone. But it appears that they don't know very much about what actually is installed in their coaches. For instance - I have two diagrams, same drawing numbers, same rev. numbers, same dates, same draftsman, same title block - but the drawings are different. Go figure.

Forget trying to find the wiring in question. Try running a wire (replacing the OEM yellow wire) from the relay to the altenator and see what you get for charging.

Interesting that you recommend that RVW. Just last night I pulled out a 50 ft. length of #12 stranded wire last night to do exactly what you said. I'll let you know what happens later today. Thanks.