i know the wiring to the fan is good because i jumped it off the battery and the fan fires right up. any ideas what might be the problem?

 

Do we assume it is a 95 Civic si?
What do you mean "i jumped it off the battery" jumped to where? 94

 

sorry about being so vague. i was watching something on tv when i typed it out the first post

its a 95 civic si w/ b16a swap. there is a plug that connects to the radiator fan that it gets its power from. i hooked the radiator side of the plug directly to the battery and the fan turns on. so, im not sure if the problem lies within that plug or a temp sensor or what?

 

check the fuse under the hood or maybe your relay on the driver side, bolted right next to the headlight should be two of them, hope this helps

 

fuse is good.

 

^x2 check your relay

 

Relay or thermostat switch.

 

Sorry, I do not have a wiring schematic for a 95 Civic so I am not sure if the rad fan relay supplies the rad fan with a ground or 12V+, probably 12V+.

We already know it is not a rad fan problem, so it must be either no power or no ground.

The first thing to do is test at the plug, [wire harness side] is there a ground, [or power] at one of the pins?

If there is a power or a ground at the plug then I would move on to the rad fan relay and supply whartever is needed, [12V+ or ground] to the lead that runs from the relay to the rad fan, to elliminate wiring or a connection as the problem.

If rad fan works when you do the above test the relay to make sure it works, if so, move to the "Engine Coolant Temperature Switch" it supplies the rad fan relay with a ground to energize it.

You can even start at that end, [ECTS], unplug it and supply a ground to it, [relay side of plug], if rad fan turns on, replace the ECTS. 94