Temp gauge. Help Willcox!
Thread Starter
Burning Brakes
Joined: Mar 2010
Posts: 803
Likes: 4
From: Christchurch, New Zealand
Temp gauge. Help Willcox!
Hi. I've got a 74 with a temperature gauge that reads like the fibre washer is missing. But it's there! The terminal post isn't grounding out on the can, and the resistor seems fine. If I wiggle things around, I sometimes get a reading as if there's no ground. I believe I briefly got a correct reading at one stage which got me pretty excited, but only fleeting. Any ideas?
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,850
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Ok... This reading could also be confused with the missing ohms signal very easily. What happens to the gauge when you ground out the sender wire?
If nothing happens and with the key on, get a test light and go to the gauge terminal for the ground (9 o’clock) and using the hot terminal (6 o'clock) for a 12 volt power source, briefly touch the ground terminal. Does the test light come on?
If no.. briefly touch the terminal stud for the ground (9 o’clock) and see if the light comes on.. (Briefly)
If the light comes on then I'd remove the terminal from the gauge ground at the 9 o'clock stud, inspect and clean the terminal.
If no, the I’d verify power and ground on the connector.
If you have power and ground there after the test above and you still have the same reading, you have a gauge issue.
If nothing happens and with the key on, get a test light and go to the gauge terminal for the ground (9 o’clock) and using the hot terminal (6 o'clock) for a 12 volt power source, briefly touch the ground terminal. Does the test light come on?
If no.. briefly touch the terminal stud for the ground (9 o’clock) and see if the light comes on.. (Briefly)
If the light comes on then I'd remove the terminal from the gauge ground at the 9 o'clock stud, inspect and clean the terminal.
If no, the I’d verify power and ground on the connector.
If you have power and ground there after the test above and you still have the same reading, you have a gauge issue.
Thread Starter
Burning Brakes
Joined: Mar 2010
Posts: 803
Likes: 4
From: Christchurch, New Zealand
Ok. Grounding out the sender wire with the key on shows a no ground reading. Using my multimeter, I got a reading of 14.3v between the power terminal and ground on both the plug and the gauge. Terminals are clean. The gauge still reads like a missing washer! Time for a new temp gauge?
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,850
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
It sure sounds like it.... The only other thing I can think of would be to double check that the resistor is not in some way touching. Then I'd opt out for a gauge.
Melting Slicks
Joined: Oct 2003
Posts: 2,122
Likes: 795
From: Chapel Hill NC
2025 c3 ('68-'73) of the Year Finalist - Unmodified
2025 C4 of the Year Finalist - Unmodified
2025 C8 Stingray of the Year Finalist - Unmodified
My 68 NOM BB temp gauge was acting like the washer wasn't there even though there was one there. Replaced the washer and the gauge worked correctly. Assuming the washer was deteriorated.
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