Article thanks to Bill Main

Date: Mon, 15 Feb 1999 10:42:07 -0600

305 Temp Sensor Location:

Between the #1 and #3 spark plugs.  #1-#7 plugs are on the driver's side.
#1 is near the front of the car.  #3 is just behind it.  The thermostat
housing should be plugged with a dummy vacuum sensor.

Common Problem:

Wire comes loose from the temp sensor.  Gauge reads erratic numbers.  Almost
looks like it is spinning completely around at times.  Caused by three
values:

1.)  Ground (max temperature) when it touches the heads, headers or steering
linkage (look for burned wire against #1/#3 primary)

2.)  Temp sensor reading.  No problem here other than loose connection.
Resulting in 1 and 3.

3.)  Open (0 temperature) when the wire is not touching anything.


Quick Check before replacing the sensor:

Go to Radio Shack and obtain the following part numbers for $1.50 + tax.  It
may take a couple of days to get the RSU items.  Or try the same ohms and
numbers at your local Auto Parts store.

        1.]    271-1301                Resistor, Axial, 1/4 watt, 5% tolerance, 10-ohm.
        2.]    RSU 11344637      Resistor, Axial, 1/4 watt, 5% tolerance, 56-ohms.
        3.]    RSU  11344884     Resistor, Axial, 1/4 watt, 5% tolerance, 1300 ohms.

Engine off and cool.  Place (2) between #3 primary and the wire.  Key to
run.  Your temp gauge should read about 260 degrees.

Engine off and cool.  Connect 1,2,3 together.  Then place between your
primary and sending wire as before.  Key to run.  Your temperature gauge
will read about 100 degrees Fahrenheit.

If either of these fail, by more than a little bit, then your tear your dash
apart and start troubleshooting the gauge.  Your sending unit will NOT fix
the problem.


Problem areas with the gauge:

1.)  Not "seated" correctly in spring terminals it lives in.
2.)  Chevy's PCB has bad connection near where the rear-defogger switch
lives.
3.)  Spring Terminals are not seated on PCB well or are dirty.


Hope this helps out Jeff
If not let me know.  I'll try to help some more.

Bill
87 Monte Carlo SS "The Adolescent"
98 Monte Carlo LS "The Year-Old"


-----Original Message-----

could someone tell me if the stock temp sensor for the in-dash guage is
on the thermostat housing? my guage quit working in the dash, and the
plug is broken on the housing.