Coach/ chassis solenoids

WA

Wakesupremo

Advanced Member
Joined
Oct 21, 2025
Posts
39
Location
East Anglia
Hi again. My 1989 gulfstream 8272 sp has 3 big relays/ solenoids under the hood. One of them had the main battery terminals linked out so the battery lead was removed from the battery to stop it going flat. It was the top left one that was linked. The two top solenoids have coach/ chassis printed on them.
When the battery lead is put back on the battery, the right hand light (chassis) comes on on the switch panel at the entry steps. I have replaced the solenoid as I thought it was faulty, however, its made no difference. It seems as if its always getting power from the switch panel. Are these switch panels available?
 
IMG_0775.jpeg
IMG_0778.jpeg
 

Attachments

  • IMG_0779.jpeg
    IMG_0779.jpeg
    128.8 KB · Views: 8
Thought I posted this paragraph and diagram below yesterday, but here it is even if late... From your pictures, it appears that the coil wires on the small studs of the COACH relay may be reversed -- and this would make the rocker off position just keep the relay on. Does the relay change state if you actuate the rocker to the ON position?


The coach and chassis power disconnect relays are latching, so they retain their last state without drawing additional power themselves. Attached is a document that shows how they work and the last page gives a good representative wiring diagram with the remote actuation rocker switches shown.

Chuck

another thing to check is the condition of the small fuses built into the relay body...if they get blown the coil will not be energized and no change in relay state can be called for by the remote switch. I see fuses in your chassis relay, but not in the coach relay... Both of the relays have "coach" labels on them, but from inspecting the wire runs that can be seen in the picture, the right one is most likely the chassis relay...


1762358445528.png
 

Attachments

  • Intelletec battery disconnect relay manual 53-00066-100.pdf
    206.2 KB · Views: 5
Last edited:
Thanks for the reply. Yes the fuses are all ok. It seems that the switch at the step doesn't work in the downward position therefore not operating the relay. I fully understand the workings of the relays. I have had them on a bench and they work fine. The new one that i bought doesn't? It wont unlatch at all!!!! The fuse holders were broken on the left hand side relay So ive replaced them with inline fuses!!
 
Now that I have read through the attached document, I am certain that the switch isn't changing over the polarity. It must be either the switch or the circuit board. The switches are soldered to the circuit board so, Im guessing, if the board is available its easiest to swap the board over.
 
I saw the inline fuse and thought that might be the case...

You can verify the relay function by applying 12 volts of each possible polarity to the actuation coil right at the relay -- this will isolate it from any issues with the remote switch in the step well. Let us know if it switches/latches correctly when locally stimulated, and then you can trace the failed control wiring that runs to the remote rocker...

The fuses provide power to the remote rocker switches on the red and orange wires, and indicator LED drive voltages on the green and yellow wires. Your pictures show two versions of the relay with the red and yellow wires (plus one shot has a heavy battery cable on the right hand power stud...) so they must have been taken at different times. Maybe your added external fuse holders are not connected correctly??? This would also cause the board and remote rocker to not work as it should...
 
I have taken each fuse holder from the battery terminals and fixed to the wire that was on the other side of the relevant fuse. Basically copied what was there but instead of the fuse being connected to the solenoid it is remote.
Both indicator lights illuminate when the batteries are connected, the chassis indicator will not 'go out' and the solenoid will not unlatch when the chassis switch is pressed downwards. The coach switch works perfectly.
I can only find single devices available not double.
 
Can you verify that the relay switches as it should when you stimulate it locally and not by the remote switch/panel??
 
Thank you for the information it is very helpful. Yes I can verify that but not tonight. Im in UK and its now pitch black!!! I can easily do that tomorrow and get back to you. Once again, Thank you.
 
Hi again. I braved the rubbish weather and dark night and went out with a torch and spare battery. If I swap the leads from side to side the solenoid works as it should. That definitely tells me that it isn't getting the correct signal from the switch. Looks like i need to find another switch board or get one made.
 
Glad to hear the relay can function as it should !! I am not sure WHICH leads you swapped, however...

The relay has a total of six connections on each relay -- the two very large studs are the contacts that are opened and closed to connect the battery bank to the system load, the smaller studs are the coil of the relay that are energized momentarily in one polarity or the other to switch and latch the relay contacts, and the small free wire leads to the two fuses connect to the control panel as indicated in the diagram below:

1762369933689.png

So, which wires were swapped? When the solenoid "works as it should" does the indicator LED also work correctly?

Chuck
 
Last edited:
I noticed your pictures of your relays show quite a bit of fading on the text labels.

Just a bit more information that might be helpful: These relays are labeled with two colors of type to show which wire colors are used in each of the two applications. you can see in the image below the black text labels are related to the 'coach' function and the red text labels are for the 'chassis' application. You may have it all correct already, but worth a verification...

1762374287810.png
 
Once again. Thank you for this information. I removed the wires from "s' and 'I'or the coil wires and, with another battery and 'jump leads' touched them one way and it latched, then swapped them and it unlatched.
I probably should have mentioned that I am , in fact, an electrician but had no wiring diagrams etc to go with. Your information is very helpful.
 
Good to know that you substituted the control wiring with a local 12 volt source and verified the solenoid functions properly !!

You may be able to repair the control board you have now, as there are only passive components on it (switches, a relay, resistors and LEDs...) Again,the panel and control harness wiring is shown in this diagram:

1762442505118.jpeg


Note that the reversing control voltage to actuate the coil of the solenoid is supplied by the chassis battery rocker switch momentarily when the switch is moved off the center position. The two wipers of this switch are connected to
the violet and grey wires of the harness which drive the solenoid coil. When the switch is moved to actuate the relay, both voltage and ground are switched as needed to cause the relay to latch open or closed. Note that this drawing has an error on the lower switch -- the two center poles should be ground and the two outer poles are meant to go to +12v just like the upper switch is drawn.

If your control board has the ignition lock-out relay as shown in the lower part of this diagram...perhaps this relay has dirty or burned contacts that keep the lower switch from functioning properly.

Hopefully you will find a simple issue that you can fix locally and not have to buy in an expensive replacement board (particularly with the hassles of import, etc...) Can you post pictures of the component side of your control board?

Let us know what you find...

Chuck
 
I thank you once again. I have been resoldering the board where things looked a bit cruddy and, hey presto, Its worked. At least thats one issue ticked off the list. Now to try to sort the pesky fridge wiring. Thats mainly sorted except from a blue wire with a spade on, its not the light as that works, but theres no terminals left on the board to put it on!!!
 
You must log in or register to reply here.

Similar threads

reddog-SKO
2008 Gladiator Emergency Start Solenoid Location?
dramey
dramey

New posts

Featured Campgrounds

Reviews provided by

Try RV LIFE Pro Free for 7 Days

  • New Ad-Free experience on this RV LIFE Community.
  • Plan the best RV Safe travel with RV LIFE Trip Wizard.
  • Navigate with our RV Safe GPS mobile app.
  • and much more...
Try RV LIFE Pro Today
Back
Top