Does anyone know the part number and where to get the adapter to put a mechanical temperature sensor in the passenger head? The plug that came out of the head is 12MM x 1.5.

I am wanting to put in a sensor for electric fans.

Classic Industries showes an adpter, SP3041 12mm coolant sensor adaptor $19.99
Not sure if this is what you want??

Does it use a crush washer? Do you need a sensor or a switch?

Painless sells a non-adjustable GM fan relay kit with M12 x 1.5 switch. Don't know the "on/off" temp though and it's $75.

Hayden 3651 is an adjustable temperature fan relay kit with screw in sensor for $45 that comes up under a 2005 Silverado with 5.3 but it doesn't say that the sensor is M12.

Other than that, Autometer 2277 is an M12 x 1.5 (with crush washer) to 1/8" NPT adapter. $9
Derale 16720 is an electric fan relay kit with 1/8" NPT switch and 180 degree "on" temp. $35

Are you running an ECM? If you are you will want to keep the factory one in the left head for the ECM and add the second one to the right head.

Don

Thanks guys for the reply. Yes it has the ECM and that is why I am putting the sensor in the passenger head. The drivers head already has the sensor in it for the ECM.

I am still debating on the fan controller. I am looking at the A1-electric # FANPWM-V3 and temp sensor and have used the digitial dakota fan controller on the last car I built.

Does it use a crush washer? Do you need a sensor or a switch?

Painless sells a non-adjustable GM fan relay kit with M12 x 1.5 switch. Don't know the "on/off" temp though and it's $75.

Hayden 3651 is an adjustable temperature fan relay kit with screw in sensor for $45 that comes up under a 2005 Silverado with 5.3 but it doesn't say that the sensor is M12.

Other than that, Autometer 2277 is an M12 x 1.5 (with crush washer) to 1/8" NPT adapter. $9
Derale 16720 is an electric fan relay kit with 1/8" NPT switch and 180 degree "on" temp. $35


Good question,,does it need a crush washer. I guess it depends on what kinda adapter you get. It depends on the threads of the adapter. Are they tapered or straight?

A temp sensor will screw into the adapter just like in the picture above.

So what have you LS guys used to sense the temp to turn on your fans. I want it to go on the passenger head.

Good question,,does it need a crush washer. I guess it depends on what kinda adapter you get. It depends on the threads of the adapter. Are they tapered or straight?

A temp sensor will screw into the adapter just like in the picture above.

So what have you LS guys used to sense the temp to turn on your fans. I want it to go on the passenger head.

Why don't you use the ECM to control the fans instead of a separate controller? That is what most do. That way you can add the second sensor for your temperature gauge.

Don

Why don't you use the ECM to control the fans instead of a separate controller? That is what most do. That way you can add the second sensor for your temperature gauge.

Don

Good idea, I will check into this.

Why don't you use the ECM to control the fans instead of a separate controller? That is what most do. That way you can add the second sensor for your temperature gauge.

Don

The LS3 motor comes with the intake and carb. The ECM/ECU is made by MSD for GM. So it has no control for the fans.