Battery Boost Solenoid Location? - 2007 Gulfstream Class C

[wearenh]

.

My boost (Aux Start) solenoid is not working (alternator doesn't charge the house batteries, and
house batteries don't help start the engine, also no "click")... so I looked for it and cannot
find it anywhere .. Here is where I looked:

• under the hood
  
• under the chassis below driver
  
• in elec dist box

So... I wrote to Gulfstream, and they sent me these two diagrams, and the relay is not
in either of these places that I can see...

anyone have another suggestion?... Thanks in advance

[wearenh]

pnichols wrote:

enblethen wrote:
Engine on, the solenoid clicks, and the alternator charges the house batteries

Just because the solenoid clicks when the engine is running does not mean that the coach batteries are getting charged very well from the alternator....I have permanent voltmeters mounted...

yes, good point ... but mine does actually work now, house battery voltmeter read 12.7 until
click, 13.6 after click, 12.9 when engine turned off ... maybe it hasn't failed yet because
it has been disconnected (loose connection) for years!! 🙂

.

[enblethen]

Quote was from Wearenh.
Pnichols is correct that just because you hear a click does not mean contacts are closing. I carry a spare charge/ignition relay with me as mine are the same type.

[pnichols]

enblethen wrote:
Engine on, the solenoid clicks, and the alternator charges the house batteries

Just because the solenoid clicks when the engine is running does not mean that the coach batteries are getting charged very well from the alternator.

In 10 years, I am now on our 3rd battery boost/charge solenoid in our Class C motorhome.

The solenoid can click into engagement alright, but with lower than normal alternator output voltage being applied to the coach batteries' terminals. Lower charging voltages seen by the coach batteries means that they may be charging slower than they should be - if much at all while traveling down the road.

With current flow over time the solenoid contacts oxidize/corrode over time such that the contacts present high resistance to current flow. During current flow, this high resistance reduces the voltage that gets applied to the coach batteries' terminals.

You can check the condition of the solenoid's contacts by measuring alternator output voltage with the engine idling and then also measuring the voltage on the coach batteries with the engine running. If these two voltage readings differ by much, then the solenoid's contacts are compromised and you will find that between camping sites the coach batteries aren't getting brought back to a full or near-full charge.

I have permanent voltmeters mounted on the dash in our Class C, so that I can see alternator output voltage and voltage on the coach battery terminals both at the same time whenever the engine is running. If these two voltmeters always read very close to each other than I know that the coach batteries are getting charged the best that they can be by the alternator and that hence, the boost/charge solenoid is both .... engaged .... and has contacts that are still in good condition.

[enblethen]

It is not only charge wire but auxiliary start power.

[Harvey51]

Wow, 2 gauge wiring in the charging wire! My eye was drawn to the lower diagram in the first post where a #2 red wire goes from the engine battery to a relay and on to a 120 amp fuse and the house battery. Of course it doesn't indicate where the relay is located.

Mine has 12 gauge wire which seems adequate as I have never seen more than 6 amps flow to the two house batteries.

[enblethen]

Loose connection!

[wearenh]

.

ok ... last post ... amusing ending

• I purchased a Cole Hersee 24213 to replace the non-working one
  
• I took apart the Distribution panel, as the drawing showed the solenoid on the back of the exposed panel
  
• I tugged and pulled carefully, and was able to see that YES it is there!!
  
• I kept trying and trying, carefully so as not to disturb the myriad of connections
  
• They just didn't put any service loops in, and many of the wires are very thick and stiff (2ga)
  
• I started to worry that I'd break some unseen connection, and spend the rest of my life chasing it
  
• I started justifying that it has been like this for a long time, and I haven't needed this function
  
• I rationalized that I can always use the Generator to charge, I don't need the alternator while driving
  
• All this while pulling and tugging, tugging and pulling
  
• 
  
• I am not one to give up on projects... I hate the thought of it
  
• 
  
• Finally, I decided to give up, the risk just wasn't worth the reward.
  
• I carefully pushed it all back in, all the wires, all the connections
  
• I reattached the box to the chassis frame, I reattached the panel to the box
  
• I reattached the cover, I reconnected the house battery
  
• I worried if I had done any damage, had broken any wires....
  
• I went inside the RV and started checking functionality to make sure
  
• 
  
• The solenoid now works!... go figure! ...
  
• Engine on, the solenoid clicks, and the alternator charges the house batteries

I guess I didn't give up, I just knew when to stop!... yippee!!

.

[enblethen]

Be aware that the aux relay is not that special. Most NAPA stores stock them. It is a simple continuous duty relay.
Glad you found it!

[wearenh]

.


aha! ... thanks for that advice, but you can see in the pic that ours only has
three breakers there (the fourth is for slide out units) ... but the reason
I said "aha" is that to answer your question, I looked at the diagram again, and
found the reference to drawings CE1562 and CE1563, and... with the magic that
is Google, pulled those up. One is for the four breaker version, and one (see below)
is for the three breaker version. It clearly shows the Aux Start Solenoid
on the BACK SIDE of the panel!!

thanks!!!

[enblethen]

Follow the wire off the 100 amp circuit breaker. Left side should have two red wires, one comes from battery and the other should go to the Aux start relay.

[wearenh]

thanks for your responses so far!

1. The "Boost" switch is a momentary SPST over the driver's head

2. The House Batteries (two T-105s) are fully charged as is the Chassis Battery

3. The House Batteries are located aft of the left side rear axle, in a compartment that
also has the "Distribution Panel". In the pics below, you can see that the Distribution
Panel mimics the Gulfstream diagram, except that the "Aux Start Solenoid" is not
there, instead there is a square black relay

4. Staring at these pics for a while, I think I will look behind this panel... it appears
the the black jacketed cable coming from the square hole and going to the lug on the
bottom of the fuse block just may be the "6ga Red" wire from the right terminal
of the solenoid ... I will start disassembling further tomorrow and will update

5. JaxDad, it certainly looks as you said, that the solonoid in the Distribution Panel
is only energized by the momentary boost switch, so that must be the Aux Start
relay (solenoid)... and that there must be a charge relay (solenoid) under the hood.

[enblethen]

OP:
Where are your coach batteries located?

[ronfisherman]

Interesting, Wire diagram say for a C's except Kodiak. Diagram looks the same as my wiring.
On my MH the solenoid/relay is located next to circuit breakers shown in the drawings.
Newer models than mine (2004) have a plastic cover for all the items in drawing. Looks like a black box about 12"X12".

[pnichols]

If this can be of any help:

In our Itasca the auxiliary start solenoid (relay) is also the "charge" solenoid (relay).

Whenever the ignition switch is ON, this relay is also engaged so that the engine start battery and the two 12 volt coach batteries are all connected up in parallel with each other. This way the alternator is charging three 12 volt batteries at once whenever the engine is running.

Right next to our auxiliary start solenoid is another solenoid. This 2nd solenoid is the one that connects and disconnects the two coach batteries from the coach system by a switch that is on the wall right next to the entrance door.