Home » Public Forums » GMCnet » Low Coolant Module (Earlier version?)
| Low Coolant Module [message #282020] |
Mon, 13 July 2015 16:50  |
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thainglo
Messages: 132
Registered: March 2015
Location: Iowa
Karma: 2
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Senior Member |
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While flushing the coolant in my new 76 Eleganza, I decided to check on the low coolant detection system. Even with the radiator drained, no light came on the module (ignition switch in RUN). Read thru the service manual and its troubleshooting procedures. Disconnected single wire from sensor, no light. Checked fuse (which should have been the first step imho), still no light. Points to either a grounded circuit or bad module. With e wire disconnected from the probe, no continuity was found to ground, so I'm guessing bad module.
Went digging around the forum and found Gene's pictures of his module and the schematic:
http://www.gmcmhphotos.com/photos/low-coolant-module/p47339-img-28332.html
Mine looks similar, but is a three wire system, not four. Pink (12v), black (ground) and yellow (probe).
The guts are different as well. While Gene's shows an integrated circuit, mine is straight resisters and transistors.
http://www.gmcmhphotos.com/photos/miscellaneous/p58457-low-coolant-module.html
So a couple of questions:
1) anyone familiar with how the system functions? Based on what I'm seeing in the board, I'm guessing the probe is heated up then some how tested for signal? If it just went to ground when the coolant was low, that could be wired directly to the LED.
2) is there a detailed schematic out there to troubleshoot?
The module jimk has also shows the four/five wire system, so im guessing that won't do the trick either.
Regardless, not the end of the world, but it got me curious.
Thanks for any help!
Matt
Matt Sladek
1976 Eleganza II
Coralville, IA
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| Re: Low Coolant Module [message #282042 is a reply to message #282020] |
Mon, 13 July 2015 19:34  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Bulb?? Did you check the bulb? And socket connection.
I remember doing a press event car show for Chrysler with a concept car that died during rehearsals. No one could figure out. Flew an engineer in from Dertroit. .......... Out of gas.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Low Coolant Module [message #282423 is a reply to message #282407] |
Sat, 18 July 2015 21:27 |
Kingsley Coach
Messages: 2691
Registered: March 2009
Location: Nova Scotia Canada
Karma: -34
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Senior Member |
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Matt
I'm on email so I may have missed something, but I think you will fit in
well here. You ask a question and then discuss it with yourself and an
imaginary friend named John !
I only see 2 messages on this subject and both are from you... Yes,
I checked the spam and trash sites for once before commenting.. ???
I don't know much about this topic but maybe I should. Since '96 when I
bought mine, I haven't seen the light come on...maybe I should follow all
other postings on this topic in case mine is not working....
Mike in NS
On Sat, Jul 18, 2015 at 5:27 PM, Matt Sladek wrote:
> Wish it was that easy John! Found out more about the modules and why
> mine isn't working. Must have been hit by a voltage spike, the 12v solder
> trace
> is fractured and the diode casing crumbled. Everything else looks really
> good, so hoping to make those repairs and be good to go.
>
> Need some help identifying the diode that connects the 12v and ground. It
> is the small black component with the white band, near the connector. Can
> someone send me any identifying numbers on the diode?
> --
> Matt Sladek
> 1976 Eleganza II
> Coralville, IA
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Michael Beaton
1977 Kingsley 26-11
1977 Eleganza II 26-3
Antigonish, NS
Life is too short to hold a grudge; slash some tires and call it even !
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| Re: [GMCnet] Low Coolant Module [message #282427 is a reply to message #282423] |
Sat, 18 July 2015 22:53 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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At first I use to think that the low coolant light was overkill, buy it has
been a great attention getter when it comes on.
I have the Digipanel but on a cool day, the temp . does not go up enough
to warn me, but the low level does tell you the coolant level is getting
very low.
On Sat, Jul 18, 2015 at 7:27 PM, Kingsley Coach
wrote:
> Matt
> I'm on email so I may have missed something, but I think you will fit in
> well here. You ask a question and then discuss it with yourself and an
> imaginary friend named John !
>
> I only see 2 messages on this subject and both are from you... Yes,
> I checked the spam and trash sites for once before commenting.. ???
>
> I don't know much about this topic but maybe I should. Since '96 when I
> bought mine, I haven't seen the light come on...maybe I should follow all
> other postings on this topic in case mine is not working....
>
> Mike in NS
>
> On Sat, Jul 18, 2015 at 5:27 PM, Matt Sladek wrote:
>
>> Wish it was that easy John! Found out more about the modules and why
>> mine isn't working. Must have been hit by a voltage spike, the 12v solder
>> trace
>> is fractured and the diode casing crumbled. Everything else looks really
>> good, so hoping to make those repairs and be good to go.
>>
>> Need some help identifying the diode that connects the 12v and ground. It
>> is the small black component with the white band, near the connector. Can
>> someone send me any identifying numbers on the diode?
>> --
>> Matt Sladek
>> 1976 Eleganza II
>> Coralville, IA
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
>
> --
> Michael Beaton
> 1977 Kingsley 26-11
> 1977 Eleganza II 26-3
> Antigonish, NS
>
> Life is too short to hold a grudge; slash some tires and call it even !
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Low Coolant Module [message #282428 is a reply to message #282427] |
Sat, 18 July 2015 22:58 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Why are you losing coolant from a pressurized, closed system? Must be a
leak somewhere I would think.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Jul 18, 2015 8:53 PM, "Jim Kanomata" wrote:
> At first I use to think that the low coolant light was overkill, buy it has
> been a great attention getter when it comes on.
> I have the Digipanel but on a cool day, the temp . does not go up enough
> to warn me, but the low level does tell you the coolant level is getting
> very low.
>
> On Sat, Jul 18, 2015 at 7:27 PM, Kingsley Coach
> wrote:
>
>> Matt
>> I'm on email so I may have missed something, but I think you will fit in
>> well here. You ask a question and then discuss it with yourself and an
>> imaginary friend named John !
>>
>> I only see 2 messages on this subject and both are from you...
> Yes,
>> I checked the spam and trash sites for once before commenting.. ???
>>
>> I don't know much about this topic but maybe I should. Since '96 when I
>> bought mine, I haven't seen the light come on...maybe I should follow all
>> other postings on this topic in case mine is not working....
>>
>> Mike in NS
>>
>> On Sat, Jul 18, 2015 at 5:27 PM, Matt Sladek
> wrote:
>>
>>> Wish it was that easy John! Found out more about the modules and why
>>> mine isn't working. Must have been hit by a voltage spike, the 12v
> solder
>>> trace
>>> is fractured and the diode casing crumbled. Everything else looks
> really
>>> good, so hoping to make those repairs and be good to go.
>>>
>>> Need some help identifying the diode that connects the 12v and ground.
> It
>>> is the small black component with the white band, near the connector.
> Can
>>> someone send me any identifying numbers on the diode?
>>> --
>>> Matt Sladek
>>> 1976 Eleganza II
>>> Coralville, IA
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>>
>>
>>
>> --
>> Michael Beaton
>> 1977 Kingsley 26-11
>> 1977 Eleganza II 26-3
>> Antigonish, NS
>>
>> Life is too short to hold a grudge; slash some tires and call it even !
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
>
> --
> Jim Kanomata
> Applied/GMC, Fremont,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] Low Coolant Module [message #282429 is a reply to message #282407] |
Sat, 18 July 2015 23:12 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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Senior Member |
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It's faded. Looks to be a 1N4001
Ill snag the one from the parts coach tomorrow. It might be better.
Anyone have a schematic on this module?
Dolph Santorine
DE N8JPC
Wheeling, West Virginia
1977 ex-Palm Beach TZE167V100820
1-ton, Sullybuilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010,
> On Jul 18, 2015, at 4:27 PM, Matt Sladek wrote:
>
> Wish it was that easy John! Found out more about the modules and why mine isn't working. Must have been hit by a voltage spike, the 12v solder trace
> is fractured and the diode casing crumbled. Everything else looks really good, so hoping to make those repairs and be good to go.
>
> Need some help identifying the diode that connects the 12v and ground. It is the small black component with the white band, near the connector. Can
> someone send me any identifying numbers on the diode?
> --
> Matt Sladek
> 1976 Eleganza II
> Coralville, IA
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: [GMCnet] Low Coolant Module [message #282447 is a reply to message #282444] |
Sun, 19 July 2015 07:28 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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Senior Member |
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Cool
On Sunday, July 19, 2015, Matt Sladek wrote:
> Thanks Dolph, that would be great. Based on how it is soldered (in
> parallel), I have been guessing it was a Zener diode to shunt over voltage
> to
> ground. However, a 1N400X would function as a protection against reverse
> voltage. Both good. Would you mind snapping a picture?
>
> I hand-drew a schematic to get a better understanding of the circuit. Not
> too pretty, but one I get the diode identified I can post on the photo site.
>
>
> Thanks again!
> --
> Matt Sladek
> 1976 Eleganza II
> Coralville, IA
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: Low Coolant Module [message #282448 is a reply to message #282020] |
Sun, 19 July 2015 07:51 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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If the diode is across the input and ground, you ought to be able to use pretty much any 1 - 3 amp diode. 1N4001 on up. As long as you're replacing components, you might want to put one of these across the input 12V to ground: DigiKey P7291-ND. 50 cents a whack, it's a 20 volt varistor. They save electronic things when your alternator sense wire goes Dixie and the voltage gets silly.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] Low Coolant Module [message #282461 is a reply to message #282444] |
Sun, 19 July 2015 12:12 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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Senior Member |
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Matt
It's a Zener and is a 1n5244
I'll send the pictures.
Seems like one of the PO's did some, ah, modifications or alleged repairs.
Dolph Santorine
DE N8JPC
Wheeling, West Virginia
1977 ex-Palm Beach TZE167V100820
1-ton, Sullybuilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010,
> On Jul 19, 2015, at 6:48 AM, Matt Sladek wrote:
>
> Thanks Dolph, that would be great. Based on how it is soldered (in parallel), I have been guessing it was a Zener diode to shunt over voltage to
> ground. However, a 1N400X would function as a protection against reverse voltage. Both good. Would you mind snapping a picture?
>
> I hand-drew a schematic to get a better understanding of the circuit. Not too pretty, but one I get the diode identified I can post on the photo site.
>
>
> Thanks again!
> --
> Matt Sladek
> 1976 Eleganza II
> Coralville, IA
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
_______________________________________________
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| Re: Low Coolant Module [message #282536 is a reply to message #282020] |
Sun, 19 July 2015 19:47 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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I don't b'lieve I'd put a Zener looking straight at the battery where the 1N4001 is shown. For sure not one as small as 14V. That would be why the trace burned off the board. There's no current limiting except blowing the fuse or burning the trace off the board when the voltage goes to say 14.2V. If it were me, I'd hang about 15 Ohms in the power feed, and use a 16V zener at a minimum. Which Zener needs to be around 5 Watts or better.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: Low Coolant Module [message #282659 is a reply to message #282020] |
Mon, 20 July 2015 20:25 |
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thainglo
Messages: 132
Registered: March 2015
Location: Iowa
Karma: 2
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Senior Member |
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Just to wrap this up, wanted to let the group know that all is well with e world, or at least as far as Matt's coolant module is concerned. Johnny was able to talk me off the ledge with some incredibly detailed info on the circuit through some off-site emails. I'm keeping the 1n4002 diode and going to add a varistor as he mentions above. Hopefully this thread and pictures will help if others need to tackle one of the three-wire systems. I wonder when they changed...?
Thanks again to everyone here at GMCnet who helped. To reference another current topic re Facebook, the knowledge and helpfulness of this community, wherever it is located, is one of the best reasons to own a GMM!
And to Johnny - it took an ice cold beer this afternoon to stop the brain melt!,
Matt Sladek
1976 Eleganza II
Coralville, IA
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