Does anyone know where the ground wire is for the temperature gauge?

I've changed out the thermostat, both temp sensors (one in thermostat housing and one next to coolant outlet port), but my temp gauge still isn't working. Tach and speedo are both fine.

Wiring all looks good.

 

Remove the yellow/red wire from the single pin coolant temp sensor for your gauge. Turn the ignition key on to position two. Touch the barrel connector to a ground and quickly check the temp gauge... if the needle is going up toward the red... then the gauge and wiring are good. Your new sensor would be bad. If nothing happens, you either have a break in the yellow/red wire OR the temp gauge is bad.

 

My temp sensors are both 2-pin (I have the D16z6 SOHC VTEC engine.)

The sensor on the thermostat housing has one green and one black wire going to it. The one next to the coolant outlet has one red/white and one green/white.

I'm not sure which one drives the temp gauge? And if I jump the two pins on that connector will it do the same thing as you're suggesting on the one-wire version?

 

It is the ECT sending unit.

 

I tried jumpering the two pins on that connector, but I got a CEL and no response from the temp gauge. (CEL went away when I reconnected the sensor.)

Does that mean the gauge might be bad? I am using an aftermarket ECT sensor, so maybe I should try a Honda one before replacing the gauge?

 

It supposed to be only a one wire (yellow/grn - yellow insulation with a green stripe) connector. Make sure you're locating the correct connector.

 

Well, hot damn - thank you so much!

I had replaced the fan switch and the ECT sensor but didn't see the ECT sending unit until you sent me the picture. Fortunately I already had the part - when it came in I thought I had ordered the wrong part, but turns out it was exactly what I needed. Temp gauge works perfectly now.

Much obliged!