The green plug closest to the blue fitting. Whats it called and whats it for?

 

Wow nice plug what engine?

 

looks like the knock sensor

 

The knock sensor is the one on the far left.

 

Yes and oil pressure is one bottom right.

 

It's a radiator fan temp switch. Used primarily on the OBD0 engines, theres a big rubber boot with 2 connectors inside that slide over it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Slurp56 &raquo;</TD></TR><TR><TD CLASS="quote">It's a radiator fan temp switch. Used primarily on the OBD0 engines, theres a big rubber boot with 2 connectors inside that slide over it.</TD></TR></TABLE>

Also called an ECT right?

Thanks for your help guys.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SYNSEI &raquo;</TD></TR><TR><TD CLASS="quote">

Also called an ECT right?

Thanks for your help guys.</TD></TR></TABLE>

Well, it is an engine coolant temp sensor, but not THE Engine Coolant Temp Sensor. You've actually got 3 of them on your motor. A 1 wire on the side of the head feeds the temp to the temp gauge in the cluster, a 2 wire on the side of the head feeds the ECT to the ECU, and then you've got this one which basically at a certain temp will short those 2 lugs inside the switch providing a ground for your radiator fan (turning it on).

This is why you can have a radiator fan not work, but your temp gauge does and your ECU doesnt throw a CEL. If you go into a parts house and ask for the ECT, chances are you wont get this part. You need to tell them its a radiator fan switch.

 

Very useful information. Thanks again.

 

Also, that is NOT the knock sensor on the left. That is the oil temp sensor for the 90-91 B18A Integra. Yes, the one on the right is the fan switch.