Atilla

iTrader: (1)

Thanks for the update Mazsufer

Jon316G

iTrader: (1)

Nice job Mazurfer!

ASH8

Ah, it depends on how you view it...this is a Normally Closed "Switch" is made of TWO Parts...the Reed and then the Magnet, without either the "switch" is useless.

So this is classed as a Normally Closed switch.

Without the Magnet the REED is Open, with Magnet the reed is closed, is is NC..

The PCM is reading resistance..

I can post a pic of a House Alarm NC Switch...almost identical and for 12-14V use.

ASH8

BTW, who is arguing...Dave??

Naturally if you slide the magnet LOW enough (as in low coolant) the REED Switch Opens, causing a Coolant Light..

The PCM is reading resistance, because if one "Normally" unplugged the Plug, you are opening the circuit ..ie.. like the reed switch, but you are not seeing a dash light.

So the PCM is reading resistance, as a REED Switch is either Closed (Normal with magnet) or Open when magnet moves far enough...there is no in between, it is at a point where the magnetic field (Float magnet) is far enough from the reed to Open the Two REED strips...Opening the Switch or circuit.

Mazurfer

Dave

Mazurfer

ASH8

Well Dave, my past life is also a Home Monitored Alarm system licenced installer, Made in Australia by Clipsal, I have fitted hundreds, the Magnetic REED Switches that we (I) install above Door and or on Widows, so when a intruder OPENS the DOOR or Window, the magnetise part (usually installed on the "moving object") OPENS the REED Switch, so it Opens the Circuit, triggering an Alarm or in this case a Coolant Low warning....in the "trade" these switches are known as a NC one, Normally Closed, which it is when the TWO parts are together..

Here is a pic of an ALARM REED Switch I have 6 in fact and they all the same, the exact same design principal as the Mazda Coolant switch..
Sorry, the pic is Blurry but you will have to trust me without the Magnet the Two REEDs are Apart, with the magnet the reeds are closed (completing the circuit).

The 'Clipsal' Reed Switch REEDS are much closer together in distance apart when the switch is Open. When a magnet (the other part you see) is moved closer there is an "Audible CLICK" when the two metal strips touch or come together..creating a Normally Closed switch.

I repeat these switches are classed as NC because the "Magnet" is part of the Switch.
It is not separate to the switch, when you purchase the reed switch the two are a pair.

They can not be classed as (NO) Normally Open because the Magnetic Round Float "Closes" the reeds, so the switch is NC.
That is the "Normal Position of the Switch"..not the other way around...sorry Dave you are wrong here.

ASH8

BTW: This house alarm Reed Switch also operates on a 12V Powered Systems (transformed down from our normal 240 Volts) , along with PIR's or Passive Infrared Detectors, Key Pads, Main Circuit Boards and Sirens.

I will try and get a better pic...sorry it is a shocker!

ASH8

Hang on Dave.....
From your own pic of the REED without a Magnet near it you can plainly see the REEDS are Apart, Not Closed, yes?..


OK, so as you are the one who has taken this float mechanism apart (thank you BTW), this REED part must be located to-wards the bottom inside of the tube or tank??

I see.... this magnet is probably a very weak one, it floats at the top with coolant, as coolant lowers the magnet then closes the reeds, (and would answer another thought I had), based on the 12V REED Switches I install the Magnet Closed the Reeds Full time. When it Opens or Magnet moves away reed open and triggers light or alarm.

What did not make sense for me was the fact that if you disconnect the Coolant Bottle switches power plug most were not getting a dash light....becasue normally with an NC switch as soon as ANY parts of the Circuit is Open or cut this will trigger a warning or light..

So yeah this makes more sense now...and it also demonstrates Mazda's issue
with these coolant tanks.

Sorry Dave, Please accept my apology, in this case this type of Reed switch is NO.
Normally Open...but IMO it does not make ANY sense.

I am now wondering WHY Mazda have made this circuit this way?.
The unreliability of the the outer tube warping because of heat and then possibly jamming the Magnetic Ring.

As I see it is is a heat issue, the RX-8's and other cars here (Australia) have to have Headlamp Washers if you have HID lamps (it is a design rule law), our tanks have a float and warning lamp and I have not heard of issue with these Cold Water/Fluid Reservoirs.

SO, yes it appears in this case the Mazda switch is NO., and explains a lot to me why owners who disconnect their plugs are not seeing a dash light, because if the switch was NC (like the house ones I fit), a un-plugging should set off a dash lamp or warning.

IF guys are saying they are getting a warning lamp when they unplug, then this does not make any sense as ALL the Replacement Coolant Tanks fit ALL RX-8 models...the latest Update tank with fit a 2003/4 model RX-8.

So I can't understand why they are seeing a warning lamp, this is another reason why this issue confused me Dave and led me to believe what I said.

Any thoughts as to why some RX-8 owners are seeing a dash light when they unplug?

Edit...I should un-plug my 09 Coolant Tank and see what happens, but they use the same tank as the Series I's?..

ASH8

Dave...

Here is an Oz website link on REED Switches, note how they say they are NC...Not NO..

http://www.swintech.com/reed_switches.htm

The first two Surface switches are the ones I install and have a pic of above..

There is one 'NO' shown...that is because there is no magnet...

In any reed switch with a magnet they are classed as a NC switch.

Jon, the Reed Switch Glass does not have any fluid inside, the reeds are made and cased with hermetically (air tight) sealed glass.
The REEDS are De-activated Rhodium.

Here is a Reed Switch, these contacts are actually OPEN, I know it does not look like it but they are ,and is the same distance open to the ones I have here, I would say about 1 to 1.5 mm.

Mazurfer

I think they do..........it can't hurt anything if you do.

Mazurfer

It's all semantics Ash..............From one encyclopedia.

The reed switch is an electrical switch operated by an applied magnetic field. It was invented at Bell Telephone Laboratories in 1936 by W. B. Ellwood. It consists of a pair of contacts on ferrous metal reeds in a hermetically sealed glass envelope. The contacts may be normally open, closing when a magnetic field is present, or normally closed and opening when a magnetic field is applied. The switch may be actuated by a coil, making a reed relay, or by bringing a magnet near to the switch. Once the magnet is pulled away from the switch, the reed switch will go back to its original position.

Mazurfer

^..................yep, that's a NO switch. It's open until you bring a magnet into play, then it closes.

Jon316G

iTrader: (1)

I understand how a float/reed switch works, I was just trying to figure out how some people would receive a "low level" light after the harness was disconnected.
My assumption was fluid in the bulb was conducting a small amount of current as "feedback", but you guys mentioned it doesn't.
Only other way is a short... possibly in the harness.
Oh well... a lot of good information here guys

ASH8

Yep, the 09's~ have the same tank, mine has the N3H1-15-350J which supersedes to a L, which then goes to an M, which I think is the "last or latest so far"...and yes the N3H1-15-350M fits ALL Series RX-8's of ANY Year..

So yes, Jon, I can not understand how guys are seeing a dash light when they disconnect the wiring plug to their coolant bottle?...

Perhaps there is a possibility that Mazda changed the PCM (ECU) way of reading the voltage or NC/NO???, it is a nightmare to try and work this one out as by part number there are SO many ECU Assemblies which depend on the cars VIN Number...I could study it to try and see if the "Bottle Changes" by part number and Vehicle VIN corresponds to any changes to the PCM assy's VIN...

...Frankly can't be bothered at the monemt...

Jon316G

iTrader: (1)

Funny story (or one that made me chuckle)....
Couple days ago at work I was working on a water chiller used for radiators in our reflow ovens.
The display kept flashing "Add Water", but the water level was fine.
I drained the tank and removed the float switch and found "gunk" preventing the float from traveling.
First thing I thought about was this thread and I looked at the display and saw the "Add Water" light was not illuminated anymore.
So that got me thinking again about this discussion... always thinking about the 8

Anyway... sorry for the side story. Back to the thread.

Lord ET

iTrader: (1)

Coincidence? I think not!

Mazurfer

Yeah, I think "M" is the latest and that's what I have. I still want to have someone say for sure that when they disconnect that they get a light. I can see where I(and maybe others?) read too much into threads about the coolant bottles? It's either that or they did change the way it's done and PCM as you've pointed out. I'm still not convinced.

Okay, now for my funny....errrrr........sad story! At least it has a happy ending and a little more data!

So last night as I was finishing up my little experiment with the old sensor and magnet, I drop the freakin magnet into the engine bay!

Couldn't find the SOB anywhere...........not underneath the car, not in the lower tray, no nook and cranny....so after about an hour, I just made sure the fans would turn by hand and that it wasn't jamming up one of those and called it quits.

Well, it pissed me off all night so this morning I look again, and still no luck.
At this point I just say screw it and remove the battery and the tray to have a better look. Of course I find it hidden down beside one of the fan shrouds, so I feel alot better about that!

So while I'm dicking around and putting it back together, I decide to go ahead and do one last experiment.

Everything is plugged in and normal with the "good" sensor/bottle.

I start the car and verify no coolant light.

Walk around and unplug the coolant sensor connector, walk back and verify no coolant light.

Here's where it gets different. Note: the car was still running(that's the only way there is any voltage to the sensor).

I had previously stripped back the wire insulation a little bit on my old sensor on the non-ground side wire, so I then hooked my meter between there and ground.

I plugged the "old" sensor in(the magnet was in my hand) and read 14.2v to ground, walked around and there was no coolant light on the dash.

I then slid the magnet onto the shaft and down to where it would rest(if low coolant) and the meter went to just about 0v. Walked around to look..............and of course had a low coolant light.

Just for grins I slid the magnet off and on several times while looking at the voltage on the meter and the dash light going off and on. Even if you look at the electrical schematic, you can see that one side of the reed switch is ground, so all it does is pull 4T of the PCM low, and the PCM turns on the low coolant warning light. It's probably a simple resistor divider network inside the PCM.

Again, not sure if they changed the design, but in order for people to have a low coolant light with connector unplugged, they somehow have to have a short between the violet/white wire and ground..................or, there are different versions of this setup running around.






^................notice this bend as has been pointed out before. This could very well be some of the issue in that when you run low on coolant, especially when redlining and it draws more from the bottle, you could be heating it up enough to induce this bend(like me). And crud build-up certainly won't help either. I think the key is of course is to change coolant probably once every two years at minimum, flush bottle of all the crud(probably have to take it out to reall accomplish, and of course keep coolant close to the full line.

Mazurfer

Think it's mainly crud build-up that takes ours out Jon. I can also see it being some heat related issues as the shaft bends and restricts magnet movement, but I think crud is the main issue.

Reflow of what? Just curious.

MazdaManiac

iTrader: (3)

Wow. Giant thread.

Just unplug it. Problem solved.

If you aren't the type that likes to check their fluids ever (and, therefore, need the sensor), just take the bottle out, plug the holes, fill it with white vinegar, let it sit over night, drain it, blast it with compressed air and put it back in.
Once again - problem solved.


BTW - I use the coolant light/circuit in my car for the low bottle output on my water/meth. Its a little more important than the low coolant light.

Mazurfer

Yeah, I know Jeff.
It was much longer than it needed to be.
And....I won't even go into the fact of the "minimal importance level" in the grand scheme. Guess I was bored!

The confusion factor is still how some reported the light on with the sensor unplugged. That doesn't make sense.

MazdaManiac

iTrader: (3)

[QUOTE=Mazurfer;3342233]Yeah, I know Jeff.
It was much longer than it needed to be.
And....I won't even go into the fact of the "minimal importance level" in the grand scheme. Guess I was bored!


No no no! I applaud your efforts! I just wanted to point out for those that are less concerned with the science and more with the result that fixing the sensor is pretty easy and requires no disassembly.

Yeah - that's not possible. An open condition is the normal state for the circuit.

Nubo

I would think something like Lime-Away or C.L.R. would clean up the inside of the bottle in a jiffy. Then rinse several times thoroughly with clear water. Worth a shot if it's acting up.

ken-x8

I'm still a little confused about the final answer. If you want the light off, is the answer:

A. Unplug the connector, and stash the loose wire somewhere out of harm's way?

or

B. Unplug the connector and short the connector on the wire before stashing it?

One other question... Do many cars these days have a sensor and warning light for coolant level? Until I got my 8, the technology was to look at the bottle every now and then. Before that, the technology was to take the radiator cap off and look in the hole.

Ken

Mazurfer

"A" until proven otherwise.

Yeah....the old school way was to just check the level in the radiator. Kinda like checking your tire pressure with a gauge...........ya know?