[C320-list] temp gague

[Stephen Cox]

> Sorry to add on to an existing thread but I suspect my 
> initial email went into spam files again (not sure why but 
> it's happened before) So I'll try this route. On first start 
> up of the season I notice the temp gauge read over 180 with a 
> cold engine (Yanmar 3gm) Shut down engine and with key off 
> temp gauge was at baseline Turned key on and again over 180. 
> Engine temp was room temp with an infrared thermometer. Took 
> off wires to temp sensor in the out line to the water heater 
> and gauge remained at base line even with key on. Any ideas 
> and is there a troubleshooting procedure for the temp gauge 
> on the website like there is for the fuel gauge?


The testing procedure was outlined in a message back in 2010.  hope you
findit useful.

Regards,

Stephen Cox
Tegwen #1141


SPECIFIC TEST PROCEDURE FOR TEMPERATURE GAUGE USED BY CATALINA YACHTS

(Other systems may use a different procedure.)

There are FOUR major sources of temp gauge problems.

1 - The temp GAUGE in the engine control panel may be defective.

TEST PROCEDURE : Disconnect BROWN sender wire from "S" terminal on gauge.
Turn on ignition switch. Pointer must deflect to extreme left. By
temporarily shorting together the "S" (sender) and the "G" (ground) studs,
pointer must deflect to the extreme right. Re-connect the BROWN sender wire
to the gauge after the test.

2 - The brown SENDER WIRE may be DISCONNECTED from the sending unit at the
engine or SHORTED TO GROUND.

TEST PROCEDURE: Disconnect brown SENDER WIRE from terminal at sending  unit
on engine. Attach brown wire to a KNOWN GROUND, such as engine block or
battery NEGATIVE. DO NOT ASSUME THE BODY OF SENDER IS GROUNDED. Turn on
ignition switch. Pointer must deflect to extreme right, as in previous test.
Disconnect brown wire from ground. If pointer STILL deflects to extreme
right, brown wire is GROUNDED at some point between the sender and gauge.
Check ALL connection points on brown wire or replace the entire wire.

3 - The SENDING UNIT may not be properly grounded to the engine block.

TEST PROCEDURE: If the gauge tests "GOOD" and BROWN wire tests "GOOD", touch
BROWN wire to the BODY OF THE SENDER.(the flat area where you would place
the wrench to install the sender.) Make sure this area is free of paint. If
pointer does not deflect to right, (as in test above), the sender body is
NOT GROUNDED. Remove the sender, and inspect the threads. If necessary,
remove any TEFLON TAPE or PIPE DOPE COMPOUND. Clean the threads, apply some
coolant to the threads, and reinstall the sender in the engine.

4 - The SENDING UNIT in the engine may be defective or the wrong unit may
have been installed.

TEST PROCEDURE: If the gauge tests "GOOD", the BROWN wire test "GOOD", and
the SENDER GROUND tests "GOOD" the sending unit in the engine is defective
or the "WRONG" unit may have been installed. The "CORRECT" sending unit has
a specifaction of:

STEWART WARNER, 240 TO 33 OHMS RESISTANCE

There are several other resistance specifications available but those
sending units WILL NOT WORK in this application.

TEST PROCEDURE, W/TEMP GAUGE
PANEL DEPARTMENT April 22, 2003
* WHITTIER, CA. 90601 * * SEAWARD PRODUCTS *