Finicky temp sender

[02fanatic]

Hugo's temp gauge keeps pegging the red when I drive him (even when he's stone cold...then I wiggle the wire and it seems to be ok. It's the original 90-degree spade fitting, so I'm thinking the wire must be all corroded inside. But, I wonder if its the sender too. How can I check the sender? I'm "really inept" when it comes to electrical stuff...I call it being electronically "challenged"! :-) I do have a multimeter however.

Thanks,

John

[Contraband]

I thought my fuel sender was busted because the needle was pegged at full (I found out the hard way that it was wrong), but I hooked up a multimeter to it and the resistance was fine. It turns out the gauge was not grounded correctly. Make sure the nut on the back of the dash panel that corresponds to the temp gauge is grounded to the car, because that might be why it's pegged at the top.

[MatthewCervi]

In addition to possible grounding problems, the gauges go bad sometimes too. I was fighting an overheating problem for a while on my car until I finally tried swapping out the gauge and it turns out the engine was fine. Fortunately I had two spare clusters so I could verify which one was accurate.

[RonR]

The original grounding for the temp and fuel gauge does not hold up very well. I rebuilt my gauge cluster and really cleaned and worked on the 2 grounding nuts on the back of the gauge cluster. After a year of aggravation I finally ran a new ground wire and the gauge has been solid ever since.

[02fanatic]

How can I tell which connection on the back of the cluster is the ground? Is it obvious? I just can't picture it.

Thanks,

John

[Jack]

John, when I first put the 72 on the road I had a new motor and unlimited paranoia over the temp gauge that wouldn't stay down. As a backup and for peace of mind I did the 3 gauge VDO install with oil and coolant temps and volts.

[John_in_VA]

to the PCB. Make a "Y" with insulated wire, run the upper ends of the "Y" under the nuts, and find a good ground for the lower leg of the "Y".

[jetboy]

a sender costs about 10 dollars, - i got one for under 8 with some other parts as well, so if all your wires look good its not a huge layout to replace the sender and see if that fixes the problem before you think about the guage itself.

[Jack]

McCartney pg 156. "checking the temp gauge and sender unit". Can't detail now, gotta get off to work.

[02fanatic]

(nt)