New battery disconnect.....

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4DogsRV

4DogsRV

Well-known member
Joined
Apr 18, 2013
Posts
47
Location
North Carolina
Good morning all,

I had previously posted that my battery disconnect solenoid was not functioning properly. Now I am in need of help once again.

I replaced the battery disconnect solenoid on my 34D in the hope that the coach batteries would then get a charge from the alternator while I was driving. I was getting 12.6 DCV on the batteries without the engine running, and was looking for about 13.6 - 13.8 DCV once I had started up. To my utter frustration, this was not the case. Question is, do I need to put a "load" on the coach batteries to draw current before I test them?

I have tested the solenoid with the multimeter (on resistance) but have had conflicting answers on what the reading should/should not be. Options?
 
Mark - there are two solenoids that are probably mounted very close together.  One solenoid is always energized unless you disconnect power to the house - there should be a switch near your door that operates this disconnect solenoid.  The other solenoid is the one that's energized when a) you operate the "Battery Boost" switch, or when the engine is running.

Sounds like you replaced the wrong solenoid.  Have a look at my solenoid replacement write-up, I show both solenoids.
 
John,

I think you may be right about having replaced the wrong solenoid. I was just "in there" again. The battery disconnect solenoid is the one on the right (and as you so rightly said, they are situated very close together). There is an audible click when I hit the switch, but the battery voltage stays the same when the engine is running (12.6 DCV). There is a 5 amp spade fuse on the top of the left hand side of the solenoid, and room for one on the right, but that slot is empty. The fuse is OK. I did a resistance test on the solenoid. I have no resistance (a reading of 0.00) when the solenoid is disconnected, and a reading of 4.4 when I hit the switch. Can anyone tell me if the solenoid is bad, or do I have to start a trace back from the alternator?
 
Here is another thought that just occurred to me. If I did replace the wrong solenoid, can I then not just take the old one that I removed and switch out the battery disconnect solenoid with it?
 
If they are the same type, switching would be ok. One may be continuous duty (or latching) and the other momentary in which case the momentary duty solenoid would likely burn out if energized continuously.

Ernie
 
They are different types of solenoid. The battery disconnect solenoid is a latching solenoid that is only powered momentarily and changes state when a voltage is applied, while the battery isolation solenoid is a 100% duty cycle solenoid that is powered when in use. Although it looks like a starter solenoid, it is different. The starter solenoid is only powered while the starter is turning and not continuous.
 
I realize my error in thinking that the two solenoids are the same, (of course they are NOT). I think my frustration got the better of my common sense and knowledge..... I guess I was just grasping at straws :)
 
Have you checked the voltage on both sides of the solenoid?  My coach had a manual resettable circuit breaker, that was tripped, not letting it charge from the alternator. I replace it with an automatic resettable one after I broke the original one.
 
There's about a 99.9% chance that if you are not seeing >13 volts on the house battery bank with the engine running and you have > 13 volts on the chassis battery, then the battery mode solenoid is bad (the solenoid that bridges the house and chassis banks together when the engine runs.)

I've been through three Trombetta failures and there is no point in trying to meter the Trombetta solenoid, just replace it.  I do recommend replacing it with either a Blue Sea product or a solenoid rated at 14 volts (continuous duty cycle.)  As I recall the Trombetta is rated at 12 volts and we suspect a high failure rate is due to a higher than designed for voltage on the coil over a period of time.

If you search this Winnie board for Trombetta, you will find my thread from three or four years ago where I did a postmortem on a failed Trombetta.
 
Something that happened today just added to my confusion/mild frustration. I did a simple test (something I should have thought about earlier) - I had the engine running and, as usual the voltage at the coach batteries was only 12.6 DCV. I then had my wife operate the battery boost switch on the dash. The voltage went up to 14.3 DCV. This means that the solenoid is working, right?? When she released it the voltage dropped slowly down to below 13 DCV. What does this prove? Herein lies my frustration, if the solenoid is working, what is the reason for the coach batteries not getting charged while the engine is running?
 
That solenoid is working. You may have another solenoid that is close to that one that is supposed to charge the batteries. Did they charge from the alternator before?
 
John Hilley said:
It implies that the 12 volts from yhe ignition switch isn't getting to the solenoid.
Click to expand...
John is correct.  That solenoid is operated when a) the Battery Boost switch is manually operated or b) when the ignition switch is on.

For a temporary fix, you can stick a toothpick or something similar in the switch to keep it operated when the engine is running so your house batteries will charge.  Call Winnebago Owner Relations and ask them for a copy of the appropriate drawing so you can troubleshoot the wiring.
 
For a temporary fix, you can stick a toothpick or something similar in the switch to keep it operated when the engine is running so your house batteries will charge.
Click to expand...

heh,heh, Reminds of a funny story. We used tooth picks all the time to hold relays operated or non-operated  at work. The big round ones worked best with the style of relays we had.

We had recently been forbidden to go for lunch at a local tavern (bar) due to a recent problem involving a couple of our salesmen.  But the bosses were also on a savings kick at that time and, as a result, we had run out of toothpicks. We facetiously asked the boss for permission to go for lunch "across the road" and promised to each have a club sandwich and bring back the toothpicks as we needed them for that afternoon. He reluctantly granted us permission but when we arrived back at the office with the 'slightly used' tooth picks, we found a large box of the same kind awaiting us.

Memories!!!! ;D
 
[off topic]
LOL - the graveyard shift guy at an unnamed Bell System central office trained me to be his night relief guy.  First thing he did was walk me around and showed me which alarm release buttons he would toothpick in the operated position so the bells wouldn't go off.  Not exactly the model employee.
[/off topic]
 
John Canfield said:
There's about a 99.9% chance that if you are not seeing >13 volts on the house battery bank with the engine running and you have > 13 volts on the chassis battery, then the battery mode solenoid is bad (the solenoid that bridges the house and chassis banks together when the engine runs.)

I've been through three Trombetta failures and there is no point in trying to meter the Trombetta solenoid, just replace it.  I do recommend replacing it with either a Blue Sea product or a solenoid rated at 14 volts (continuous duty cycle.)  As I recall the Trombetta is rated at 12 volts and we suspect a high failure rate is due to a higher than designed for voltage on the coil over a period of time.

If you search this Winnie board for Trombetta, you will find my thread from three or four years ago where I did a postmortem on a failed Trombetta.
Click to expand...

John, thanks for the tip on Blue Sea.  My house battery disconnect solenoid on the Allure has failed and CC wanted $250 for a replacement :mad:.  I was going to try and get a good continuous duty 200 amp solenoid from NAPA until I saw this post.  The Blue Sea 9012 looks exactly like the solenoids CC put in this coach.  I was able to get one from Amazon for $158. 
 
On my Sightseer the wire from the RUN terminal that activates the MODE solenoid when the engine is running is fused. You might want to take a look at the wiring diagram to see where the fuse is  or call Winnebago customer service and ask them.
On mine (Workhorse chassis) the fuse is in the upper right side of the fuse block under the dash. It is labeled  "Step Alarm"
There are other items activated by the wire from the same fuse - back up monitor, step retraction when the ignition is on, and the MotorAide fan motor.
I discovered this when the fan motor shorted and blew the fuse.
 
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