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Topic: Aux Start Fuse Blowing-Upate for May!

Posted By: BoatCop on 04/02/11 07:14pm

RV Custom Products Battery Control Center. P/N CB115-Rev A
1999 Southwind F53 Chassis

Found 5 Amp Aux Start Fuse (F17) blown.

Replaced fuse.

Tested Aux Start (heard solenoid click, saw chassis battery voltage drop slightly on dash voltmeter.

Looked at fuse: Blown again.

Here's the funny part: If I hit the Aux Start Switch with the fuse blown (or even removed) I can still hear the solenoid and see the voltage drop.

Other issues:

Coach batteries do not charge from the Chassis (engine) batteries with the engine running.

Chassis batteries do not charge from the converter. NOTE: I have already determined that the converter (PD-9145) is faulty, only putting out 12.4 volts. New converter (PD-9160) on order.

I do have the RV Custom Products troubleshooting guide, but it doesn't address the fuse issue. Looking at the required coach battery voltage to allow charging of the chassis battery, I think the converter is the culprit here. But that wouldn't explain the coach batteries not being charged from the engine.

The only thing I can think of from these symptoms is a faulty solenoid. Can anyone tell me what's going on?

Note: It's been like this since I bought it, 3 years ago.

* This post was edited 05/02/11 09:34pm by BoatCop *

1999 Southwind 34L
2013 Chevy Tahoe
2001 Jeep Wrangler TJ (TOAD)
Sampson (The Bloodhound)
Delilah (The Basset)

Posted By: enblethen on 04/02/11 07:28pm

Read through page 4,5, &6 of the manual.
Sounds to me like you should not energize the aux start when connected to shore power. The converter will charge chassis battery through the system and electronic circuit board.
Do you know whether you have revision A or B?

USAF Retired
Suzuki XL7 pushing Pace Arrow

2003 Chev Ice Road Tracker

Posted By: BoatCop on 04/02/11 07:35pm

Read through 3 or 4 times. Still no answers.

Shore power disconnected. Charging from converter to chassis batteries assumes 13.2v at coach batteries. Currently charged to 12.4v from faulty converter with low volt and likely low amp output.

Revision A (as stated in my intitial description)

Posted By: enblethen on 04/02/11 08:55pm

Try disconnecting the wire on the relay to see if fuse blows. That would prove that is in the switch circuit or the relay. Could be a bad coil in the relay going to ground.

Posted By: YC 1 on 04/02/11 09:40pm

Since it has been this way for three years you may have a couple of issues. The fuse may be a bit small for the surge current of the solenoid but before going to a larger fuse do as suggested and remove that wire from the solenoid (small wire),(not large cables)and push the button to see if the fuse blows. If the fuse blows you have a short in the wire. If it does not blow you can step up the fuse size to 7.5 and press the button.

Have someone press the button for you and measure the voltages at the solenoid. If you have four wires two would be very large and they are simply shorted together when working. The two small terminals are the control circuit. Just a simple magnetic circuit that pulls in the contacts inside. You should have battery voltgage on one when the button is pushed and 0 volts on the other. If you increase the fuse size be sure to only push the button for 5 seconds or so at a time for safety. If the relay is clunking every time you push the button then measure the voltage on each of the large terminals. When the solenoid is activated you should see the same voltage on each side of the large terminals.

If the 7.5 amp fuse blows then replace the solenoid.

H/R Endeavor 2008
2013 Ford Edge toad
Full Timers

Posted By: BoatCop on 04/03/11 12:31pm

Thanks for all the input.

Once I get the new converter in I'll try the tests.

Posted By: enblethen on 04/03/11 12:55pm

You may also disconnect the output of the switch going into the circuit board. It could be a problem within the circuit board.

Posted By: BoatCop on 04/04/11 06:48pm

New converter installed and working like designed. Holds at 13.6v, even with all 12v fans and lights blazing. Hadn't done that since I bought it.

Funny thing, though. Before I put in the new PD9160A I verified my readings. Old 9155 was only putting out 12.4v (still hooked up) at the output lugs and at the battery. After I pulled it out I bench tested it and it was putting out 13.82v.

Could it be that it just wasn't putting out the necessary amps, and resistance in the wiring was reducing the voltage?

In any event, that part is now working right. As soon as my assistant gets back from her business trip, I'll check out the BCC.

Posted By: BoatCop on 05/02/11 09:55pm

OK. Found out why the fuse was blowing.

Installed a new solenoid, just to eliminate that being the problem ($14 on Ebay). Wired it up the exact same way it came off, including the small black wire on the same terminal as the yellow wire. (Not the black wire from the solenoid direct to ground, but the one from behind the board)

Sure enough, the fuse still blew.

So, laying in bed last night, contemplating replacement of the circuit board, I started to think about basic 12v electricity and remembered that black wires almost always go to ground.

Today after work, I pulled the black wire off and put it on the ground terminal of the solenoid. No more blowing the fuse, and I can see the dash lights get brighter when I push the Aux start button.

I wonder how long the guy I bought it from had it like that, or why it was put there in the first place.

However, it doesn't seem like the bi-directional charging is working. That is Converter charging the house battery or alternator charging the chassis battery.

Maybe the battery state(s) are not letting the relay kick in. The manual states that the batteries have to be charged above 13.2v. I'm not sure if that's converter or alternator output (both were putting out 14+ volts), or actual battery state. I didn't run everything long enough to find out.

In any event, I think I'm finally getting the bugs out of this thing, and learning more RV electrical stuff every day.

Now to install the inverter, and I think I'll have gone through about ALL the electrical glitches and the whole thing will finally work as designed.

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