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Does anyone know exactly how the coolant switch works?
Looking for the geek answer.
Bruce
Looking for the geek answer.
Bruce
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coolant switch?
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txmytx_catahoula
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If it's the switch I'm thinking about, located on the right side of the block near the back, it's actually a thermocouple. When the key is on, power goes to it, when the coolant is below a certain temp, IIRC 95 degrees, the switch is closed and sends power on to the fast idle solenoid and injector via the green wires on the front of the injector. When the engine coolant reaches above 95 degrees, the switch opens and stops power to the fast idle solenoid and slow the idle back to normal.
Hope this helps.
Hope this helps.
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I think he is asking about the level switch in the radiator.
Simple answer is, it "feels" the wetness and all is good. It feels "dry" and it tells the light to turn on.
This is just like when you stick your finger in the radiator and feel nothing, a light comes on in your head and says, "add coolant".
Simple answer is, it "feels" the wetness and all is good. It feels "dry" and it tells the light to turn on.
This is just like when you stick your finger in the radiator and feel nothing, a light comes on in your head and says, "add coolant".
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Ken_86gt
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It feels the wetness....very true, this could be read in so many ways..... The more geeky response would be that it is a sort of conductivity sensor- working with a module that tells the dash light when to turn on.
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Ken_86gt
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It is amazing what one can find when using a search engine.
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Correct, that is one way to get a possible answer, but there are many ways that this circuit
could be implemented, and I was curious about the one in the CUCV, not the modern day vehicle.
In particular, is the device an actual switch, or is it just enabling a circuit path to the water
and back to the grounded block. Note, the radiator itself is not grounded and there is only one lead to the device.
I was just curious as to the specific methodology of this device.
Bruce
could be implemented, and I was curious about the one in the CUCV, not the modern day vehicle.
In particular, is the device an actual switch, or is it just enabling a circuit path to the water
and back to the grounded block. Note, the radiator itself is not grounded and there is only one lead to the device.
I was just curious as to the specific methodology of this device.
Bruce
MarcusOReallyus
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Yes, including wrong answers, like the one linked above.
It's a level sensor in the sense that it detects whether or not there is water present at the level of the sensor.
It's NOT a level sensor the way a gas guage is a level sensor. It doesn't tell you that your radiator is half full or quarter full the way a gas gauge does.
All it tells you is, "Oops. There's no water here where I am."
So his discussion about the variable conductivity of water, while correct, is irrelevant at best, and misleading at worst.
(I do like the fact that he mentioned that water has "conductive minerals in it therefore conducts electricity". That's accurate. Pure water is actually a very good insulator.)
As to how the CUCV sensor works....
Bruce, I have not pondered the diagram, but just based on function, my guess is the latter. If it's an actual switch (pressure actuated, likely), then we are using the water as a conductor for a switched circuit, which would be less than wonderfully reliable. Using it simply as the ground path for a sensor circuit would be fine.
MarcusOReallyus
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No, no, no! It's only correct if I put it on the Internet!
Ken_86gt
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I still stand by the answer given by the linked page. Read it again. Once a certain level of conductivity is read by the module, a "switch" inside the module will turn the light on. The sensor on the tank is not a switch and is only a probe or sensor used to measure the conductivity.
There are level switches on other vehicles, just no this one.
There are level switches on other vehicles, just no this one.
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Warthog: Sorry, I thought that had been answered. Coolant level in the radiator, not Temp.
Ken: After looking at the schematic in the TM, my guess is that it is really just a sensor and not a
switch inspite of the nomenclature in the TM. There is probably a current flow detection circuit in the coolant module that detects the small current flowing through the device in the radiator
when the water completes the circuit to ground in the block. Once it detects the current flow, it
switches a circuit that drives the lamp circuit.
I say guess, because I find it strange that the manufacturer refers to it as a switch and not a sensor. Also because I fail to recognize the symbol used in the diagram for the device.
Thanks to everyone who responded!
One more thing of interest. If, as I suspect, the device is just a solid metal probe
from end to end, then it is unlikely ever to fail unless physically snapped off or rusted away.
So when troubleshooting I would look at this item last. Especially since an attempt to remove it
is likely to destroy it as I found out when trying to remove the old one from
the old radiator to put in the new one. It is made of a not too hard plastic insulator which tends
to crumble.
Bruce
Ken: After looking at the schematic in the TM, my guess is that it is really just a sensor and not a
switch inspite of the nomenclature in the TM. There is probably a current flow detection circuit in the coolant module that detects the small current flowing through the device in the radiator
when the water completes the circuit to ground in the block. Once it detects the current flow, it
switches a circuit that drives the lamp circuit.
I say guess, because I find it strange that the manufacturer refers to it as a switch and not a sensor. Also because I fail to recognize the symbol used in the diagram for the device.
Thanks to everyone who responded!
One more thing of interest. If, as I suspect, the device is just a solid metal probe
from end to end, then it is unlikely ever to fail unless physically snapped off or rusted away.
So when troubleshooting I would look at this item last. Especially since an attempt to remove it
is likely to destroy it as I found out when trying to remove the old one from
the old radiator to put in the new one. It is made of a not too hard plastic insulator which tends
to crumble.
Bruce
Ken_86gt
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Bruce- It sounds like you have it right.
MarcusOReallyus
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Agreed, though in a sense, it IS a switch. It's a device for completing a circuit.
But if we want to be picky (and we do, of course!
), it's actually PART of a switch, because the coolant is the other contact. The actuating arm, if you will.
But if we want to be picky (and we do, of course!
), it's actually PART of a switch, because the coolant is the other contact. The actuating arm, if you will.Ken_86gt
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I think of it more like the probes that are attached to your vom meter. I know it is Symantics and perspectives..
WARWAG
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I am currently doing a search for Low Coolant Level Light. I found this and it does answer some of my questions. How any of you had this problem? Its not discussed very much. I searched the TMs but really no help there. The problem I am having is the light keeps coming on now all the time for a few minutes then goes out. There is plenty of fluid. I was wondering if maybe the thermatstat was sticking? Anyone have a simular problem?
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My guess would be that the end of the probe has aquired a lot of rust deposits or
something that acts like an insulator. Or that the connector is loose or wire broken.
First thing I would do is have someone watch the light while you wiggle the connector
and wire.
Next, take a flashlight and look down inside the radiator and see if you can see the end of the probe to see if it is dirty.
If that isn't it, then start looking at the wiring to the module. Reseat the module
in case the contacts have started to oxidize.
Next, if you can borrow a module, try swapping out the module, although that is
not the most likely thing to go wrong.
If you are going to try removing the sensor, make sure you have a spare ready, and tools to extract the old sensor after it self destructs. along with a thread chassing tool. I don't know what size or threads though.
Good luck!
Bruce
something that acts like an insulator. Or that the connector is loose or wire broken.
First thing I would do is have someone watch the light while you wiggle the connector
and wire.
Next, take a flashlight and look down inside the radiator and see if you can see the end of the probe to see if it is dirty.
If that isn't it, then start looking at the wiring to the module. Reseat the module
in case the contacts have started to oxidize.
Next, if you can borrow a module, try swapping out the module, although that is
not the most likely thing to go wrong.
If you are going to try removing the sensor, make sure you have a spare ready, and tools to extract the old sensor after it self destructs. along with a thread chassing tool. I don't know what size or threads though.
Good luck!
Bruce
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Also check ground connections to block.
Bruce
Bruce
So I have some field intel on this problem as this has been a bug in my 09 since last fall.. Mind you mine is put up for the winter to keep the road salt from eating it alive. I have read that low coolant is associated with the injector pump as has been written here today when I did my initial fire up of the spring ran the cycle turned the key it fired right up for about 10 seconds then quite cycled 4 more times nothing good battery power etc. I went out remembering the problems from the fall and pulled the green single wires from the sensors on the IP and coolant sensor clean them up emery cloth plug everything back in and cycled again and it fired up. I do think as stated here there is something to do with the cooling sensor loop and the injection pump electronics. I won't write off this as a fix until I can get solid starts and some road time with it at different run temps. I also noted to that my coolant was low which is odd the only thing I can think of is that the heater plumbing hadn't been used in a long while and last fall that may have caused the drop in coolant which lead to the fluttering of the low coolant light coming on. I will post after more testing. I'm not sure if this report helps the OP or its a long since solved thread but I thought I would offer it up.