Electrical Issue, ARB solenoids not firing (Solved)

Joined
Jul 17, 2018
Messages
1,645
Location
LUGOFF, SC
Below is the electrical diagram for my ARB air lockers and York compressor.
The York circuit is working perfectly.

The relays that are powered from the OEM locker switch have power and cycle. Audible clicks when locker dial turned through RR and FR positions.
When the ARB plug is unplugged, the relays drop out, so I know power is being conveyed though the solenoids to ground. When the plug is reattached the relays click back in. Also there is 11.45V on multi meter between ARB plug sockets 1/2 and 3/4.
But the solenoids won't trigger.

When the solenoids are jumpered at the pin side directly to the battery, they fire perfectly.
This is where I'm lost, obviously they have power, but they won't fire when in the circuit.

When I pulled the sockets out of the Locker ECU plug, I used pins to attach the wires from factory wiring to the solenoids rather than cut and solder. They were slid in and shrink wrapped into position.
I'm wondering if perhaps the connection isn't good enough and I'm getting voltage, but not enough current. Thinking of pulling the shrink wrap and soldering the pins to the sockets.
I've got a similar issue with the confirmation light on the rear locker bulb. There's voltage through the wire, so obviously the bulb is good, but the dang thing won't light when it's circuit goes to ground. This is also why I think the pins to sockets connection is poor, showing voltage but not good enough pass current.

Any other thoughts? Pulling the connections and soldering them is what I'll do just answer my own concerns and rule out the possibility of crappy connections.
Guess I'm just mussing and talking my way through this, thanks for reading through and if y'all have any other thoughts, please let me know.

1650938915132.jpeg
 
Last edited:
Joined
Jul 17, 2018
Messages
1,645
Location
LUGOFF, SC
Yup they are in series.
are you thinking too much voltage drop?
Current stays constant in a series circuit.
 
Joined
Sep 17, 2003
Messages
4,256
Location
Sunnyvale, CA
Website
www.george4wd.taskled.com
Won't work that way. The coil needs 12V, the solenoids need 12V.

Even in a perfect world and the 2 coils had exactly the same resistance, you would end up with 6V for the relay coil and 6V for the solenoid coil... You do not wire coils in series...

And yes, that is the problem you're having. Only if you were really lucky would both coils operate and that would just be luck and not something to rely on in the field.

cheers,
george.
 
Joined
Sep 17, 2003
Messages
4,256
Location
Sunnyvale, CA
Website
www.george4wd.taskled.com
Yup they are in series.
are you thinking too much voltage drop?
Current stays constant in a series circuit.

It's not voltage drop as such.

Let's assume the relay coil is about 100 ohms and assume the solenoid coil is about 100 ohms.

Put them in series and apply 12V and you will have 12/200 = 0.060A flowing through them. With 0.060 and 100 ohms you have 6V. So, only 6V across the relay coil and 6V across the solenoid coil.

The relay coil with 12V across it (not in series with the solenoid coil) would have 12/100 = 0.12A flowing. Some 12V relays may just barely work with 6V across them, but the pull in will be pretty weak on the contacts since you have a pretty weak magnetic field with only 1/2 the rated current flowing. The solenoid may not even function or barely pull in as well with only 1/2 the rated current.

Of course you would need to measure actual resistance of the relay coil and the solenoid coil to get an idea how bad your setup actually is.

Anyhow, you need to rethink your hookup, the relay coil needs 12V as does the solenoid coil and with your existing wiring that will never be possible.

cheers,
george.
 
Joined
Sep 17, 2003
Messages
4,256
Location
Sunnyvale, CA
Website
www.george4wd.taskled.com
Yeah, if you take your existing drawing. Connect the right side of the relay coil to ground (disconnect the solenoid coil that you have going to the relay coil. Then take the solenoid coil end you freed up and connect it to the left side of the relay coil.

Now, the relay coil gets 12V from the magic dial and the solenoid gets 12V from the magic dial.

cheers,
george.
 
Joined
Jul 17, 2018
Messages
1,645
Location
LUGOFF, SC
So run the two coils in parallel.
There is certainly enough current capacity in that circuit.
I'll try that when I get a chance. Right now I'm laser focused on setting my pinion and carrier gear.
Once I get the gearing straight, I can go back to electrical.
 
Joined
Jul 17, 2018
Messages
1,645
Location
LUGOFF, SC
Edited wiring diagram per conversation above, running the ARB solenoids in parallel with the locker indicator relay: And it works as desired.
Just incase anybody else wants to use this method.

1652365058376.png
 

Users who are viewing this thread

Top Bottom