Temp gauge, '94 850

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Ron - 03 Aug 2005 12:50 GMT

Does the '94 850 have one of those odd 'middle of the dial' tpe temp
gauges, like some of the 240s?

My radiator cap cracked yesterday, and was spewing coolant for who
knows how long, until the low water light came on...the gauge never
moved from the middle. I also have noted on a hot day, with A/C on and
pulling a grade, it does not move, and in the winter moves to the
center fairly quickly.

If it does have that weird circuitry, what is the fix to have some
idea what the engine temp really is?

Ron/Champ 6

1963 8E5 Champ (Champ 6)
1962 Lark Daytona Convertible On eBay now...(Boomerang)
1995 VW Passat (Vanilla..yuk)
1994 Volvo 850 (Tilley)
1973 Volvo 1800 ES (Hyacinth Bucket)

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Mike F - 03 Aug 2005 15:08 GMT

> Does the '94 850 have one of those odd 'middle of the dial' tpe temp
> gauges, like some of the 240s?
[quoted text clipped - 15 lines]
> 1994 Volvo 850 (Tilley)
> 1973 Volvo 1800 ES (Hyacinth Bucket)

Yes, it's like that, but if it doesn't show overheating, (assuming it's
working as designed) then is really isn't. It's only to hide normal
running fluctuations from you so you don't go running to the dealer
every time you gauge goes up a millimetre higher than normal. Normally
your car's cooling system has enough reserve capacity that it won't
overheat in this situation.

Signature

Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

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Ron - 04 Aug 2005 02:03 GMT

might as well have an idiot light, then... If you don't know that the
fluctuations are normal, you shouldn't have a gauge nor a Volvo..maybe
a Chevy or something mindless like that...

( off my soapbox now)

Thanks, Mike

Ron

>> Does the '94 850 have one of those odd 'middle of the dial' tpe temp
>> gauges, like some of the 240s?
[quoted text clipped - 22 lines]
>your car's cooling system has enough reserve capacity that it won't
>overheat in this situation.

Ron/Champ 6

1963 8E5 Champ (Champ 6)
1962 Lark Daytona Convertible On eBay now...(Boomerang)
1995 VW Passat (Vanilla..yuk)
1994 Volvo 850 (Tilley)
1973 Volvo 1800 ES (Hyacinth Bucket)

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Doug Warner - 05 Aug 2005 01:54 GMT

>Does the '94 850 have one of those odd 'middle of the dial' tpe temp
>gauges, like some of the 240s?
[quoted text clipped - 7 lines]
>If it does have that weird circuitry, what is the fix to have some
>idea what the engine temp really is?

It's not a direct gauge. The temp sensor is connected to the combined
instrument module, whose microprocessor moves the stepper motor
pointer.

There's a test mode (in the 94's) to see of the pointers and odometer
are working. There's also a fault code readout to see if the sensor
is working.

Find the underhood test connectors and plug the wire into hole A7.
Turn the ignition on.

Fault codes:

1. Press the button once, briefly (About 1/4 second)
2. Watch the LED and count the groups of blinks. such as 1-2-2. When
it stops, press the button again, keep doing this until the first code
repeats.

The two temperature sensor faults are: 1-2-1 and 1-2-2.

Function test:
1. Turn ignition off and on again to reset test mode 1, and then press
the button 3 times.

2. Look at the instrument panel for the following indications:
    Fuel gauge:    Half full.
    Speedometer: Vertical.
    Tach:    Vertical.
    Temp:    Edge of the red mark.
    Odometer: Advances 5 tenths.

If the temp pointer remains at midpoint, then it's the instrument pod
($$$$)

If you had a new Volvo, the status would be impossible to obtain
without a $50.00 visit to the dealer. This is why I'm not considering
a new VOlvo to replace my 94.

BTW: The temp sensor is also used by the engine management computer,
and it it wasn't working, you'd probably have a check engine condition
by this time.
.

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