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Marcq Samba Member
Joined: June 15, 2015 Posts: 231 Location: Corona, CA
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Posted: Tue Jan 26, 2016 6:46 pm Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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SyncroChrick wrote: |
Marcq wrote: |
That f*cking flashing light is driving me crazy
And I thought I had everything figured
I noticed recently that when I paused with the key on the on position for a few second with the light flashing and then start, the light would not flash until about ten minutes later when the engine was overheating (air in the system) It made sense since(I think) the red light will flash when not enough coolant in the expansion tank OR engine is overheating
So I bleed the system properly, used the same technique(pause before starting with the key on ON) and the light would behave like it's suppose to, yeah!! Finally BUT!!
Last night I took it for a drive, put the lights on and it starts to blink again for no reason and the rpm cuts off, shut the light off and it stops the blinking and the rpm is back on
Maybe I need some Holy water and a crucifix
Marc.. |
see my previous post |
Is there a way to test that gauge? it's not a cheap part and my van is 87
Marc. |
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crazyvwvanman Samba Member
Joined: January 28, 2008 Posts: 9936 Location: Orbiting San Diego
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Posted: Wed Jan 27, 2016 7:36 am Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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The blinking led is a dual alarm. It blinks to get your attention when the coolant temp gauge reading is too hot and it blinks to let you know that the coolant level looks low in the main tank and you need to check the level asap.
The gauge itself has some electronics inside. This part can slowly go bad and make the led blink at times when there is nothing wrong with either the temp or the coolant level. This gradual electronics failure can be the most annoying to track down.
The failing electronic part inside can be replaced for $1 but it isn't at all simple unless you are already used to working on delicate circuits with a soldering iron. Replacing the gauge is the usual fix.
One easy test that may help is to wait for the next time it flashes when you know the level in the tank is ok and the needle isn't reading hot. Simply pull the "coolant level warning relay" from the dash relay/fuse panel. It is plugged into relay socket 3 and should have a large 43 or 42 stamped on the end you can see. With the led blinking away, just yank that relay out and see if the blinking immediately stops. If it still blinks then chances are you have a gauge with failing electronics inside.
Mark |
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Marcq Samba Member
Joined: June 15, 2015 Posts: 231 Location: Corona, CA
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Posted: Wed Jan 27, 2016 10:06 am Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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crazyvwvanman wrote: |
One easy test that may help is to wait for the next time it flashes when you know the level in the tank is ok and the needle isn't reading hot. Simply pull the "coolant level warning relay" from the dash relay/fuse panel. It is plugged into relay socket 3 and should have a large 43 or 42 stamped on the end you can see. With the led blinking away, just yank that relay out and see if the blinking immediately stops. If it still blinks then chances are you have a gauge with failing electronics inside.
Mark |
I'll do that
Thanks a bunch
Marc.. |
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Marcq Samba Member
Joined: June 15, 2015 Posts: 231 Location: Corona, CA
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Posted: Wed Jan 27, 2016 1:30 pm Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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Merian wrote: |
take apart all connections involved and clean them - incl. the grounds
sorry if it was a bit cryptic, but at least it wasn't a cryptical envelopment |
You were right, cleaned the grounds related to cool-temp send unit located under the ignition coil and everything works
Elementary, my dear Watson!!
Thanks, Marc.. |
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Marcq Samba Member
Joined: June 15, 2015 Posts: 231 Location: Corona, CA
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Posted: Wed Jan 27, 2016 1:46 pm Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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Back to square one everything was fine until I unplug the sensor on the expansion to see if it would start flashing, but it took about 3sec and it flashed and now it does the same thing
Basically, the gauge operates properly as long as I don't use the driving lights
Yanked the relay and it kept flashing so I guess I need a new gauge
Marc.. |
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menotti Samba Member
Joined: December 03, 2017 Posts: 65 Location: Encinitas, CA
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Posted: Sun Feb 25, 2018 3:03 pm Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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tencentlife wrote: |
Testing with an ohmmeter across the contacts of the level sensor, you will not get a zero ohm reading with a good sensor immersed in liquid. There will be several hundred thousand ohms. An infinity reading, though, would indicate a faulty sensor if it is immersed in coolant. If you read continuity across an immersed sensor, but the previous tests failed to stop the blinking LED, there may be another electrical fault, e.g. a break in the blue/green sensor wire, or a problem in the coolant low level control unit, located on the main fuse panel.
Sorry if there was any confusion caused by our failure to explain the entire procedure. Now, back to your regularly scheduled hair-pulling. |
Tested resistance at the sensor after pulling off the connector and getting a 3.65 M Ohm reading, which seems crazy. Operator fault or would this be indicating a problem with the sensor? Given that you expect a few hundred thousand ohms and I'm in the millions here.
Thanks |
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menotti Samba Member
Joined: December 03, 2017 Posts: 65 Location: Encinitas, CA
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Posted: Sun Feb 25, 2018 3:43 pm Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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menotti wrote: |
tencentlife wrote: |
Testing with an ohmmeter across the contacts of the level sensor, you will not get a zero ohm reading with a good sensor immersed in liquid. There will be several hundred thousand ohms. An infinity reading, though, would indicate a faulty sensor if it is immersed in coolant. If you read continuity across an immersed sensor, but the previous tests failed to stop the blinking LED, there may be another electrical fault, e.g. a break in the blue/green sensor wire, or a problem in the coolant low level control unit, located on the main fuse panel.
Sorry if there was any confusion caused by our failure to explain the entire procedure. Now, back to your regularly scheduled hair-pulling. |
Tested resistance at the sensor after pulling off the connector and getting a 3.65 M Ohm reading, which seems crazy. Operator fault or would this be indicating a problem with the sensor? Given that you expect a few hundred thousand ohms and I'm in the millions here.
Thanks |
Well this is weird, half the time when I test it it reads .5 mega ohm instead, which is in the range you suggest...super odd |
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menotti Samba Member
Joined: December 03, 2017 Posts: 65 Location: Encinitas, CA
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Posted: Sun Feb 25, 2018 5:23 pm Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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crazyvwvanman wrote: |
The blinking led is a dual alarm. It blinks to get your attention when the coolant temp gauge reading is too hot and it blinks to let you know that the coolant level looks low in the main tank and you need to check the level asap.
The gauge itself has some electronics inside. This part can slowly go bad and make the led blink at times when there is nothing wrong with either the temp or the coolant level. This gradual electronics failure can be the most annoying to track down.
The failing electronic part inside can be replaced for $1 but it isn't at all simple unless you are already used to working on delicate circuits with a soldering iron. Replacing the gauge is the usual fix.
One easy test that may help is to wait for the next time it flashes when you know the level in the tank is ok and the needle isn't reading hot. Simply pull the "coolant level warning relay" from the dash relay/fuse panel. It is plugged into relay socket 3 and should have a large 43 or 42 stamped on the end you can see. With the led blinking away, just yank that relay out and see if the blinking immediately stops. If it still blinks then chances are you have a gauge with failing electronics inside.
Mark |
Did the relay test and likely have a problem in the gauge itself! A relief to diagnose it.
To be clear, the symptoms and steps I took were:
- Turn ignition to battery on
- Coolant light blinking
- Wait 5 seconds or so, turn engine on
- Light continues to blink - NEVER stops
- Pull relay
- Light continues to blink
Sounds like a problem in the gauge itself with the fix being something like this, yeah? http://www.vanagonauts.com/Warning-Light-Fix241.htm |
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menotti Samba Member
Joined: December 03, 2017 Posts: 65 Location: Encinitas, CA
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Posted: Mon Feb 26, 2018 8:57 am Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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menotti wrote: |
crazyvwvanman wrote: |
The blinking led is a dual alarm. It blinks to get your attention when the coolant temp gauge reading is too hot and it blinks to let you know that the coolant level looks low in the main tank and you need to check the level asap.
The gauge itself has some electronics inside. This part can slowly go bad and make the led blink at times when there is nothing wrong with either the temp or the coolant level. This gradual electronics failure can be the most annoying to track down.
The failing electronic part inside can be replaced for $1 but it isn't at all simple unless you are already used to working on delicate circuits with a soldering iron. Replacing the gauge is the usual fix.
One easy test that may help is to wait for the next time it flashes when you know the level in the tank is ok and the needle isn't reading hot. Simply pull the "coolant level warning relay" from the dash relay/fuse panel. It is plugged into relay socket 3 and should have a large 43 or 42 stamped on the end you can see. With the led blinking away, just yank that relay out and see if the blinking immediately stops. If it still blinks then chances are you have a gauge with failing electronics inside.
Mark |
Did the relay test and likely have a problem in the gauge itself! A relief to diagnose it.
To be clear, the symptoms and steps I took were:
- Turn ignition to battery on
- Coolant light blinking
- Wait 5 seconds or so, turn engine on
- Light continues to blink - NEVER stops
- Pull relay
- Light continues to blink
Sounds like a problem in the gauge itself with the fix being something like this, yeah? http://www.vanagonauts.com/Warning-Light-Fix241.htm |
Now I am a little dumbfounded!
I checked again the overflow tank with the engine cold and even though it seemed to have an acceptable amount of coolant in there, I figured why not bring it closer to the top line just in case. I had figured this wouldn't have anything to do with the sensor in the expansion tank.
Lo and behold I start up the van and the light is NO LONGER BLINKING. Wow, I though, I am a complete moron but glad this is fixed.
I drove to the grocery store with the light off and the temp rising to a comfortable midpoint.
Come out of the store and start up the van, the light is back! What?
I am going to check the overflow once more tonight and if it is roughly in the same place it sounds like, given I did the check by pulling the relay, that I have a bad capacitor in the gauge itself, yeah? |
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menotti Samba Member
Joined: December 03, 2017 Posts: 65 Location: Encinitas, CA
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Posted: Thu Mar 01, 2018 6:26 am Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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Any thoughts on this? Sorry for double posting in the other thread too |
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Ahwahnee Samba Member
Joined: June 05, 2010 Posts: 9810 Location: Mt Lemmon, AZ
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Posted: Thu Mar 01, 2018 7:26 am Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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I would think the telling thing would be the level of coolant in the pressurized tank when the light is flashing.
I am still unclear whether you have a cooling system issue or a sensor/wiring issue.
Once you know which then you can begin to parse the possible causes.
You should probably pick one thread or the other to discuss this (or even start your own with a title specific to your problem). |
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menotti Samba Member
Joined: December 03, 2017 Posts: 65 Location: Encinitas, CA
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Posted: Fri Mar 09, 2018 3:53 pm Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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Ahwahnee wrote: |
I would think the telling thing would be the level of coolant in the pressurized tank when the light is flashing.
I am still unclear whether you have a cooling system issue or a sensor/wiring issue.
Once you know which then you can begin to parse the possible causes.
You should probably pick one thread or the other to discuss this (or even start your own with a title specific to your problem). |
Thank you, I'll send it to its own thread. |
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crazyvwvanman Samba Member
Joined: January 28, 2008 Posts: 9936 Location: Orbiting San Diego
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Posted: Fri Mar 09, 2018 4:05 pm Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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You need to do the relay test again when this temp gauge led blinking happens.
Yank the coolant level relay without turning anything off.
If the gauge blinking keeps going with the relay now out, IT CAN'T BE anything to do the the sensor, coolant level, or sensor wiring.
IT CAN'T BE!!!!!!
Now it is possible to have more than one problem happening at different times to cause blinking and that can really drive you nuts. You have to fix each problem.
Mark |
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wcdennis Samba Member
Joined: July 20, 2004 Posts: 955 Location: Winston-Salem NC
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Posted: Sat Mar 10, 2018 7:12 am Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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The capacitor in the gauge that causes the erroneous blinking, will probably not fail decisively. Instead, it my be fine when cool and then short-out when it gets warm. This can make diagnosis very frustrating. As others have said, pulling the coolant relay is the best way to narrow down the variables when trying to solve the constant blinking LED issue. |
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menotti Samba Member
Joined: December 03, 2017 Posts: 65 Location: Encinitas, CA
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Posted: Sat Mar 10, 2018 1:30 pm Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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crazyvwvanman wrote: |
You need to do the relay test again when this temp gauge led blinking happens.
Yank the coolant level relay without turning anything off.
If the gauge blinking keeps going with the relay now out, IT CAN'T BE anything to do the the sensor, coolant level, or sensor wiring.
IT CAN'T BE!!!!!!
Now it is possible to have more than one problem happening at different times to cause blinking and that can really drive you nuts. You have to fix each problem.
Mark |
Thanks, will be trying this again! Also starting this in its own thread per your recommendation. |
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Black'n'White Samba Member
Joined: May 18, 2016 Posts: 81 Location: Butte County, CA
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Posted: Wed Oct 24, 2018 5:31 pm Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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Found this thread while attempting to diagnose a flashing LED on the temperature gauge in the tach. '87 Syncro, Subaru conversion, aluminum expansion tank from Van Cafe, the level sensor in the tank only has one lead to it, and the tank itself is grounded (0.2 ohms resistance from the tank to chassis ground). Is it correct that the level sensor grounds through the aluminum tank?
This all started when the plastic overflow tank ran dry, so I suspect there's a small leak somewhere in the system. Filling the overflow tank to the max line didn't change the behavior.
Here's what it does:
Turn key to ON, LED flashes several times, stops, then about ten seconds later continuously flashes as long as the key is on. If I start the van, it does the same thing with the ten second pause. The goWesty blue film replacement kit is installed on the instrument cluster, along with the low coolant level beeper, and boy, does it get your attention!
I've got continuity in the blue/green wire from the expansion tank level sensor to the blue green wire on both sides of the big connector to the instrument cluster.
I measure 0.2 Ohms of resistance between the aluminum pressure tank housing and ground.
I opened the expansion tank and it is full to the brim. I pulled out about 500 ml of antifreeze with a turkey baster and the resistance across the sensor to ground dropped from about 32kOhms full to 22 kOhms with the level down an inch or so.
Shorting the level sensor lead to ground doesn't alter the flashing of the LED.
While the LED was flashing, I pulled relay 43 and the flashing stopped. If I plug the relay back in, after a short delay the flashing starts again.
Has anyone got a correct value for the sensor resistance range?
I'm running Prestone green antifreeze mixed 50/50 with distilled water. The engine only has about 400 miles on it at this point, so I don't think it's a corrosion problem.
Any ideas on what to check next? I'm running out of ideas...
Thanks! _________________ '87 Syncro/Westy Homebrew
Whatever it takes... |
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VicVan Samba Member
Joined: July 01, 2015 Posts: 1845 Location: Vancouver Island, BC
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Posted: Thu Oct 25, 2018 10:56 am Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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Check this out:
http://www.vanagonauts.com/index.phtml?catid=241 _________________ '90 Little Blue Truck, 2WD auto, FAS GenV 2.0 NA (AVH) |
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JRAMIREZACOSTA Samba Member
Joined: January 08, 2010 Posts: 2 Location: PUERTO RICO
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Posted: Sun Dec 23, 2018 8:47 am Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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THANKS for the post, I tried almost everything you mentioned but, not to ground directly the blue/green wire. |
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Black'n'White Samba Member
Joined: May 18, 2016 Posts: 81 Location: Butte County, CA
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Posted: Sun Dec 23, 2018 10:08 am Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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Just to follow up, my problem was resolved by replacing the coolant level sensor relay, the one with 43 painted on it in the bank of relays under the left end of the dash. Mine came from Van Cafe. _________________ '87 Syncro/Westy Homebrew
Whatever it takes... |
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Black'n'White Samba Member
Joined: May 18, 2016 Posts: 81 Location: Butte County, CA
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Posted: Fri Feb 08, 2019 3:26 pm Post subject: Re: Diagnostic: Coolant level sensor; must restart to test |
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Update:
A few weeks later and the LED is flashing again, even with the new coolant level sensor relay installed. If I pull the relay when the engine is running and the LED is still flashing, the LED continues to flash.
I've replaced the capacitor in the temperature gauge, but will check to make sure the replacement is installed correctly, polarity wise.
If the capacitor is OK, what else should I check? _________________ '87 Syncro/Westy Homebrew
Whatever it takes... |
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