acmoc

Hey.
My temperature gauge sender went out a while back. It would read cold.

I purchased one at kragen and it ended up reading overheating.
So I grabbed two oem units at the junkyard and tried both and they work well.

Then I bought another new unit at Napa autoparts and it also read overheating.

Is this a Honda only item?

Has anyone had this experience before?
The Napa autoparts guy was nice enough to return my money and he told me the sender reads from 100f to 212f.

It worried me my wiring or cluster was bad but the oem units from the junkyard nonetheless work fine.

Is there a way to check the wiring or my gauge cluster?

boibuddha

I can't say I have experience with an aftermarket unit, but the EF uses a single wire output to the cluster (assuming you still have an EF cluster).
It goes straight to the cluster, that signal is not used for anything else.

If the wiring was bad, it would just read cold, period. When you pull the connector, you have zero volts going through the wire which is represented by stone cold on the gauge.

I would assume the aftermarket units are outputting a voltage higher than the cluster is expecting.
I'm not sure what the expected voltage range would be though.
No need to buy a new one if the junkyard pieces give you an expected reading.

acmoc

Just out of curiousity I went to the honda dealer and the parts guy told me its not uncommon.
He told me 100f to 212f is nowhere near oem spec as the honda civic operates at around 200f. Which means at 200f the aftermarket sensor will send an overheat signal.

Just so odd. But I guess not many sensors have ever failed.

So that wire runs straight to the cluster?

boibuddha

Here's a diagram to help show what temp sensors do what on the D-series
Blue - Activates Radiator Fan
Red - to ECU
Blue - to Cluster


From reading some other threads, it sounds like you worked things out.