It's been hot lately, hotter than normal. With the heat came my car's first overheat (since I've had it). The radiator was replaced, as it blew a seam. A tune-up later, due to melted plug wires, and the car runs like a champ. However.

It got real hot again (100+, not normal for Portland, OR), and the car began to heat up. It was then that I figured out that the fan isn't coming on when it should; I mean the thing should be working like crazy when the temp gauge is nearly to the top, right?

The fuses are good, and I replaced the relay. Then I replaced the temprature switch. The motor is good; I jumped it to the battery and it works great. In fact, I rigged it to run constantly as I drove to my father's to work on it that hot afternoon.

After all this, the fan still won't come on. I've got a Hayne's book, and if I have interpretted the wiring diagram right, there aren't any other parts in this circuit. however, the schematic shows a noise filter in there somewhere which I haven't seen while poking around under the hood. Maybe this has gone bad?

I need ideas of what to check tomorrow after class. I am gonna start checking for a short if all else fails (it has). The car is bone stock, aside from the stereo system I put in and the remote start/keyless entry I installed months ago. I've considered that I screwed something up during some install, but I don't think I was anywhere near the radiator fan circuit...

I need input - anything you can suggest or add will be helpful far beyond comprehension. I'm starting to pull my hair out! He;lp!

Edit: Forgot to mention: its a '95 Civic LX 1.5L non-vtec

 

well you can do a temp fix by hotwiring the fan to a switch to leave it running while you drive. That'll at least let you drive around.

Why dont you try this, maybe its wiring... get a voltmeter and with the fan harness disconnected, check the voltage of the plug (engine side) while the motor is running. Maybe the fan simply isn't getting +12.

or u can just get a socketed bulb (like what the Autometer gauges come with) and stick that in the harness, then with the car running, wait for the light to come on. could be as simple as a bad connection.

ever have teh engine steam cleaned? maybe there is some corrosion somewhere.. Unplug the main engine harnesses and plug em back in to reseat the connections.

check the continuity of those lines to the fan, maye there is a break in the line somewhere.

 

jump the fan switch connector to see if the fan will gon on, if so, then there is a problem with your fan switch but since you replaced it I wouls figure it's not reading temperature correctly. So here is my guess: air in the cooling system. There is a bleeder valve on where the front hose connects, while the car is running open the bleeder until coolant runs out and check to see if there was air in the system.

 

run it from the battery to a switch. works for me.

 

First, thanks for the replies ans suggestions all.

Here's an update: I have been testing the wires and everything today, and on a whim I jumped the temp switch, bypassing it, and put the key in the 'on' position. Low and behold, the fan turned on! Now another question: is it normal for this car to only run the fan when the key is in the on position? I thought it was that the fan would come on at any time, weather the key was in or not.

Thanks again!