E: Engine Coolant Temperature Reads Inaccurately

E1 Check Water Temperature Indicator Sender Unit At Cold Reading
- Turn ignition switch to OFF position
- Disconnect water temperature indicator sender unit connector C182.
- Connect Rotunda Instrument Gauge System Tester 014-R1063 or equivalent to water temperature indicator sender unit connector C182.
- Set tester to 275 ohms.
- Turn ignition switch to RUN, wait 60 seconds and read gauge.

Does gauge read "C"?

Yes
GO to E2.
No
GO to E3.

E2 Check Water Temperature Indicator Sender Unit At Hot Reading
- Set tester to 18.3 ohms, wait 60 seconds and read gauge.

Does gauge read "H"?

Yes
REPLACE water temperature indicator sender unit. RESTORE vehicle. RETEST system.
No
GO to E3

E3 Check Circuit 39 (R/W)
- Turn ignition switch to OFF
- Remove instrument cluster as described.
- Disconnect instrument cluster connector C250.
- Measure resistance between water temperature indicator sender unit connector C182 and instrument cluster connector Pin C250-9.

Is resistance less than 5 ohms?

Yes
GO to E4
No
SERVICE open in Circuit 39 (R/W). RESTORE vehicle. RETEST system.

E4 Check Printed Circuit
- Measure resistance of instrument cluster printed circuit between the following terminals of printed circuit flex connection and terminals at gauge.

Terminal Circuit Function

C251-10 640(R/Y) Power (HOT in START or RUN)

C250-1 57(BK) Ground

C251-9 39 (R/W) Temperature Sender Signal Input

Is resistance 5 ohms or less for each flex circuit or printed circuit?

Yes
REPLACE engine coolant temperature gauge. RESTORE vehicle. RETEST system.
No
REPLACE instrument cluster printed circuit. RESTORE vehicle. RETEST system.