JCB 1CX/208 Newbie

[Trent62]

Here is a wiring Schematic of the float switch. Can you tell me from this how it should work? Maybe the schematic is not for my exact machine....?

 

[hookedondiesel]

From looking at the diagram, ( you did say this MAY NOT be for your machine)....
the relay is a normal acting relay, "on when it's on" and off when you return the switch back to off.
Have you tried swapping with another switch...I can't see anyone holding that switch down and operating the machine in float mode, I can understand if it was mounted on your joystick.
I also noticed there was a "pressure switch" (#35) in the same circuit, it seems that this switch will also activate float mode. Is there another button or switch somewhere that you are overlooking.

 

[Fred Cosworth]

1CX Float switch

From looking at the diagram, ( you did say this MAY NOT be for your machine)....
the relay is a normal acting relay, "on when it's on" and off when you return the switch back to off.
Have you tried swapping with another switch...I can't see anyone holding that switch down and operating the machine in float mode, I can understand if it was mounted on your joystick.
I also noticed there was a "pressure switch" (#35) in the same circuit, it seems that this switch will also activate float mode. Is there another button or switch somewhere that you are overlooking.

Trent62 - congratulations with persevering with this one, with what I have seen on the previous posts everyone is on the right track. Although I am no expert on automotive wiring I think the problem could be the pressure switch.

Looking at the wiring diagram it appears that the pressure switch is enabling the relay to have a latching feature . It looks like it takes the positive feed from the relay at the diode 23 when you energise it with the momentary switch and feeds it back into the relay to hold it engaged once you have let go of the momentary switch. I think that the pressure switch is normally closed and only opens when pressure is raised in the servo hose. However if the pressure switch is faulty and is already open then the relay can't latch and therefore you would only get float by holding down the momentary switch. I am guessing that the switch is a 3 position switch to allow float to be turned off at the switch as well as selecting lift ?

A simple test for this theory would be to locate the switch which I assume will be between the loader joystick and the valve block (probably easiest to trace the loader lift service hoses back to the valve block and then trace the servo hoses off that slice of the valve - normally the small flexible 1/4" hoses - somewhere there will be the switch.

If you temporarily link the 2 wires together on the switch (effectively making it permanently closed) then when everyone is clear and safe test the switch - if float works but won't switch off when selecting lift then it should be a faulty switch.

 

[hookedondiesel]

Keep in mind, that in the UK, their terminology is a bit different then ours.
"Latch" or "Latching", think of this as a "gate latch" it's either latched closed or open.
"Pressure switch" think of this as a switch that needs pressure ("held down") to operate.
The diodes are there (#38 and #37) just to stop the coils from collapsing and feeding back current into the circuit, diode #23 is there to stop current feedback into coil #38.
Don't worry to much about these, because you already stated that "float" does or did work.
From the diagram you provided, you have a "always on float" or a "float when temporarily needed" button.
Give me the part number on the "relay" #37.
Remember, a switch is a switch is a switch, the relay does all the work.
Let us know how you make out on this.:thumbsup

 

[Trent62]

Thanks for your advice guys. I tend to agree with Fred that the pressure switch creates the loop back needed to hold the relay. However, even though I was able to get the bucket into float mode a couple of times by holding the button down, it is not consistent. I may go press the button now and 1 of 3 things happens. The light on the button illuminates and nothing else happens, or the light does not come on and nothing happens, or the light comes on and the bucket floats so long as I hold the button. From what I can tell of the schematic, if the pressure switch is open the relay will not hold closed, but even if the pressure switch is open I should achieve float as long as the button is held and sending power to the relay. At one point I had the Float switch out of the arm rest and if I pressed it to the "ON" position I had power on every one of the terminals and the light was not on. I would have thought at least one terminal would be a ground. I'm starting to wonder if the switch itself might be faulty? I'll do some more tracing and testing... If I can find that pressure switch. I'll let you know what I find. Thanks again for your help guys!!

 

[Fred Cosworth]

Thanks for your advice guys. I tend to agree with Fred that the pressure switch creates the loop back needed to hold the relay. However, even though I was able to get the bucket into float mode a couple of times by holding the button down, it is not consistent. I may go press the button now and 1 of 3 things happens. The light on the button illuminates and nothing else happens, or the light does not come on and nothing happens, or the light comes on and the bucket floats so long as I hold the button. From what I can tell of the schematic, if the pressure switch is open the relay will not hold closed, but even if the pressure switch is open I should achieve float as long as the button is held and sending power to the relay. At one point I had the Float switch out of the arm rest and if I pressed it to the "ON" position I had power on every one of the terminals and the light was not on. I would have thought at least one terminal would be a ground. I'm starting to wonder if the switch itself might be faulty? I'll do some more tracing and testing... If I can find that pressure switch. I'll let you know what I find. Thanks again for your help guys!!

Hi Trent62 - It is always possible that you have more than one fault. If you temporarily bypass the pressure switch that will at least answer the question of the switch until you can find out what is wrong with the rest of the circuit.

Intermittent electrical faults can be some of the most frustrating to overcome.

It is possible that you have a faulty switch as the machine is quite old in years but still young in terms of hours.

It is quite an interesting switch as well switching the positive and negative sides at the same time.

Can I assume that it is a 3 position switch that has a momentary action either side of the middle position and is spring loaded back to that mid position when you let go of the button? One side seems redundant for some reason.

I also assume that the terminals numbered on the drawing are replicated on the back side of the switch - probably barely visible !

You mention that there must be a ground and you are right it looks like terminal 2 is that ground - terminals 6 and 9 then become the switched ground to energise the relay coil and switch indication bulb respectively.

There is an excellent book by Tracy Martin on how to diagnose and repair automotive electrical systems - it helps remind me how electrics work.

If you had positive on most terminals then the bulb wouldn't light up if terminals 9 and 10 were both positive in fact it may suggest that the mechanical part of the switch is broken preventing terminals 2 and 6 connecting.

I would make sure that the ground is good - even use a jumper cable onto terminal 2 if ground is suspect.

I would also strip down the switch and see if it is sound - they are usually capable of being stripped down if you do it slowly and record where all of the moving parts go.

Good Luck

 

[Trent62]

Fred,
Your understanding of how that circuit works is exactly the way I see it. Yes it is a 3 position switch and functions as you described it. You are also correct when you say "it is always possible that you have more than one fault", because as it turns out... that is the case. I found at least 2 problems in the circuit.

First, I did a little research and found out how to test the relay... turns out the relay was defective, so I swapped it out with another that tested good. Now if I hold down the float button I have float, but it does not stick when I release the button and the light on the switch does not illuminate. So I at least know the solenoid is working.

Next, I traced the wires down to the float circuit where I located the pressure switch. I jumped the switch so we know for sure it is closed. I momentarily depress the float switch and release it... "Voila"... we have sustained float!! I pull back on the joystick to raise the loader arms and nothing happens... just as we would expect at this point as the pressure switch is closed and disconnected so pulling back on the joystick cannot trigger the switch to disengage the float. However, I still have no light on the float switch at this point.

So I remove the jumper wire from the pressure switch and put everything back together. I decide to test the circuit one more time before I call it a night. I know the float function is not going to stick because the pressure switch is bad but it should still float if I hold the float switch down. So I raise the loader arms and hold down on the float switch... the loader slowly falls to the ground and the float switch lights up this time!!??

The conclusions drawn from this are:
1. The float circuit is functional
2. The pressure switch is defective (and must be replaced)
3. I still may have a faulty float switch given that at one point I had power to ALL terminals and that the light on the switch works intermittently.

Does anything come to mind that would cause ALL the switch terminals to have power, besides a faulty switch?
If I replace the pressure switch and have any further problems my next best guess would be to replace the float switch (or dissect it).

I think I figured out how that float switch functions. On the "+" side, the switch between terminals 1 and 3 are "normally open", on the "-" side, the switch between terminals 2 and 6 are "normally closed".

When you press the switch to on, it joins terminals 1 and 3, effectively completing the circuit. When you release the switch the loop created by the pressure switch holds the relay closed.

When you press the switch to the "off" position, it disconnects terminals 2 and 6, effectively interrupting the circuit and the relay opens, bringing us back to the "off" position.

Thanks "very much" to all who helped me with this.

 

[Fred Cosworth]

Fred,
Your understanding of how that circuit works is exactly the way I see it. Yes it is a 3 position switch and functions as you described it. You are also correct when you say "it is always possible that you have more than one fault", because as it turns out... that is the case. I found at least 2 problems in the circuit.

First, I did a little research and found out how to test the relay... turns out the relay was defective, so I swapped it out with another that tested good. Now if I hold down the float button I have float, but it does not stick when I release the button and the light on the switch does not illuminate. So I at least know the solenoid is working.

Next, I traced the wires down to the float circuit where I located the pressure switch. I jumped the switch so we know for sure it is closed. I momentarily depress the float switch and release it... "Voila"... we have sustained float!! I pull back on the joystick to raise the loader arms and nothing happens... just as we would expect at this point as the pressure switch is closed and disconnected so pulling back on the joystick cannot trigger the switch to disengage the float. However, I still have no light on the float switch at this point.

So I remove the jumper wire from the pressure switch and put everything back together. I decide to test the circuit one more time before I call it a night. I know the float function is not going to stick because the pressure switch is bad but it should still float if I hold the float switch down. So I raise the loader arms and hold down on the float switch... the loader slowly falls to the ground and the float switch lights up this time!!??

The conclusions drawn from this are:
1. The float circuit is functional
2. The pressure switch is defective (and must be replaced)
3. I still may have a faulty float switch given that at one point I had power to ALL terminals and that the light on the switch works intermittently.

Does anything come to mind that would cause ALL the switch terminals to have power, besides a faulty switch?
If I replace the pressure switch and have any further problems my next best guess would be to replace the float switch (or dissect it).

I think I figured out how that float switch functions. On the "+" side, the switch between terminals 1 and 3 are "normally open", on the "-" side, the switch between terminals 2 and 6 are "normally closed".

When you press the switch to on, it joins terminals 1 and 3, effectively completing the circuit. When you release the switch the loop created by the pressure switch holds the relay closed.

When you press the switch to the "off" position, it disconnects terminals 2 and 6, effectively interrupting the circuit and the relay opens, bringing us back to the "off" position.

Thanks "very much" to all who helped me with this.

Hi Trent62 - I think everything you said makes good sense - still interesting that the light works intermittently.

I would try stripping the switch down as you have nothing to loose as you were thinking of replacing it anyway - should save you money if successful.

 

[hookedondiesel]

Trent, what are you using to test for power, is it a test light or a meter,
if it's a meter, you have to ground the negative meter probe on a good ground surface and "leave" it there for all measurements.
I say this because you may be getting false readings with your meter if you use different ground points, and it would be impossible to have power on "all" terminals of the switch without blowing a fuse.
I'd also like to ask you, where is this "pressure switch" located?
Can you see or locate diode #23, it may also be faulty, make sure all connections are secure and tight also.
You seem to be on the right track, I'm sure you'll figure this out.

 

[Trent62]

Sorry for the late reply. Been on holidays. I ordered a new pressure switch as I am quite confident that is the float problem. I will let you know. On another topic though... Hooked up my snowblower today for the first time and all seems to work well except I cannot lift or tilt with the loader arms while the aux hydraulics are switched on and the blower is running. Turn the aux hydraulics off and the loader controls work fine again. Is this typical or should I be able to have loader controls while the blower is running?

 

[Trent62]

Just an update in case anyone was wondering....

I purchased the new pressure switch ($300 cdn) and installed it. Float circuit has been working fine ever since. Thank You all for your input!!

 

[Big T]

Can anyone tell me where the float pressure switch is located. I'm having a similar problem.

 

[AusDave]

Sorry for the late reply. Been on holidays. I ordered a new pressure switch as I am quite confident that is the float problem. I will let you know. On another topic though... Hooked up my snowblower today for the first time and all seems to work well except I cannot lift or tilt with the loader arms while the aux hydraulics are switched on and the blower is running. Turn the aux hydraulics off and the loader controls work fine again. Is this typical or should I be able to have loader controls while the blower is running?

Hi Trent.
If you don't have a separate high flow hydraulic circuit to run the snowblower then your snowblower will steal the majority of the flow from the rest of the hydraulics. So what you're experiencing is normal on a standard flow machine.
AusDave

 

[Big T]

Just an update I was able to trace a broken wire between pin6 on the float switch harness and pin 85 on the float relay harness. Had no continuity. I ran a new wire and now have float function again. Thanks again to everyone on this thread! Gave me info I needed to fix the problem.

 

[Soma]

Dobrý deň, mám záujem o ručné pripojenie elektriny k jcb 1cx, ak má niekto o tomto stroji niečo. Ďakujem