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1994 Park Avenue Low Coolant Light

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Bankerjohn

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Aug 20, 2006, 12:46:03 PM8/20/06
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I posted this problem in a Buick forum last fall, but never got a
satisfactory answer ... so I'm gonna try here! I'm getting the car
ready to sell, but I hate to try and convince a prospective buyer to
just ignore the warning light!

I have a 1994 PA Ultra with 135K miles on it ... and for the last 5+
years, my "Low Coolant" light on the dash has come on about 15 secs
after starting the car, and stays on steady until I turn the ignition
off. Coolant level is fine. Low coolant sensor in the radiator was
replaced, with no improvement.

According to the troubleshooing chart in the service manual:

"If CHECK OIL LEVEL indicator is lit continuously when oil level is OK,
or COOLANT LOW indicator is lit continuously when coolant level is OK,
check indicator lead for a short to ground. If wire OK, replace oil
level module."

Then the chart goes on in great detail about checking various
connectors for various ohms or voltages, ETC, ETC, ETC !!!!

According to the wiring diagram in the manual, there are 3 wires
attached to the "Low Coolant" sensor ... Brown (to a signal input on
"Oil Level Module"), Light Green (also to a signal input on "Oil Level
Module"), and Red/White (to power on "Oil Level Module").

Two questions:

How do I "check indicator lead for a short to ground"? Just a
continuity check for all three leads to ground? Continuity on any of
the leads = "short to ground"?

Does anybody know where the "Oil Level Module" is located?

Has anyone else experienced this same problem? Any directions or advice
would be appreciated!

« Paul »

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Aug 20, 2006, 2:07:01 PM8/20/06
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Is your sensor in the radiator or in the overflow tank?

Bankerjohn

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Aug 20, 2006, 3:00:16 PM8/20/06
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> Bankerjohn previously wrote:
> >
> > .... Low coolant sensor in the radiator was
> > replaced, with no improvement. ...
> >

The "Low Coolant Sensor" plugs into the passenger side of the radiator
above the lower radiator hose.

There is no problem with the sensor ... I had it replaced at a GM
dealership long after the lamp started coming on. I told them that it
wasn't bad, but they replaced it anyway. I'm resonably sure it's not
the sensor because the troubleshooting chart says that unplugging the
wiring harness from the sensor should make the warning lamp go out ...
mine doesn't!

Mike Marlow

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Aug 20, 2006, 7:24:00 PM8/20/06
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"Bankerjohn" <jepar...@gmail.com> wrote in message
news:1156100416.4...@i3g2000cwc.googlegroups.com...

>
> There is no problem with the sensor ... I had it replaced at a GM
> dealership long after the lamp started coming on. I told them that it
> wasn't bad, but they replaced it anyway. I'm resonably sure it's not
> the sensor because the troubleshooting chart says that unplugging the
> wiring harness from the sensor should make the warning lamp go out ...
> mine doesn't!
>

I don't believe you mentioned earlier that the light does not go out when
you unplug the connector. No shortcuts to this fix. Get out your ohmmeter
and start eating ohms.

--

-Mike-
mmarlo...@alltel.net


« Paul »

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Aug 20, 2006, 8:21:10 PM8/20/06
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Agreed.

Bankerjohn

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Aug 20, 2006, 8:37:56 PM8/20/06
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So ... back to my orginal two questions:

« Paul »

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Aug 20, 2006, 10:10:29 PM8/20/06
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I don't think I can be of further help to you. Sorry.
I do not know of an oil lev mod in a 94 Buick and can't tell you which wires are
for what with out a schematic.

William H. Bowen

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Aug 21, 2006, 5:11:11 AM8/21/06
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"Bankerjohn" <jepar...@gmail.com> wrote:

John,

Let's go back to the top. You've unplugged the coolant level sensor
at the radiator and the "Low Coolant" light is still on, correct?

Question: is the oil level indicator operating correctly?

First test is to unplug the oil level module and see if the lamp is
out. If it is (and I'd almost bet it will be) and, from the symptoms
you describe, I'm inclined to think the oil level module itself is
defective. If you had a wiring short from the module to the indicator
light it would be lit as soon as you turn on the ignition (the coolant
indicator lamp is conteolled by the yellow/black wire on Terminal #4
of the oil level module)..

The location of the Oil Level Module - mounted to the bracket of the
Relay Center, which is to the right of the glove box behind the IP. It
is the module with 10-pin flat black connector plugged into it.

If you are going to be checking around back there, be careful of ANY
wiring that has yellow connectors and/or yellow sleeving on it - that
is wiring for the air bag. DO NOT disturb any of those
wires.connectors!!

Do those tests and get back to us.

Regards,
Bill Bowen
Sacramento, CA

Bankerjohn

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Aug 21, 2006, 9:36:18 PM8/21/06
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William H. Bowen wrote:

> First test is to unplug the oil level module and see if the lamp is
> out. If it is (and I'd almost bet it will be) and, from the symptoms
> you describe, I'm inclined to think the oil level module itself is
> defective. If you had a wiring short from the module to the indicator
> light it would be lit as soon as you turn on the ignition (the coolant
> indicator lamp is conteolled by the yellow/black wire on Terminal #4
> of the oil level module)..
>
> The location of the Oil Level Module - mounted to the bracket of the
> Relay Center, which is to the right of the glove box behind the IP. It
> is the module with 10-pin flat black connector plugged into it.
>
> If you are going to be checking around back there, be careful of ANY
> wiring that has yellow connectors and/or yellow sleeving on it - that
> is wiring for the air bag. DO NOT disturb any of those
> wires.connectors!!
>
> Do those tests and get back to us.
>
> Regards,
> Bill Bowen
> Sacramento, CA

Bill ... thanks for the educated reply!

Yikes ... I released the two rubber tabs that keep the glovebox from
falling down when you open it ... to reveal a vast number of wires and
"modules" behind the dash! With flashlight and reading glasses in hand,
I looked for the relay center (which I believe I correctly identified
against the right-hand side) ... but I didn't see anything with a
"10-pin flat black connector plugged into it"!

Am I going to need to remove the lower portion of the dashboard to get
to the module ... or am I just blind?

William H. Bowen

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Aug 23, 2006, 12:55:58 AM8/23/06
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"Bankerjohn" <jepar...@gmail.com> wrote:

John,

The oil level module is not plugged into the relay center: it is
mounted to the bracket that holds the relay center. You may have to
drop that lower dashboard panel to get to it.

Bill

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