I'm really not very good with electrical stuff, so all of the DIY walk throughs on how to do this on the internet have really done nothing but confuse me more.

My fan doesn't come on like its supposed to. I suspect its a wire problem, because of some of the shoddy wiring that I've already dealt with in this car.

Where should I start and what exactly should I do? I think I remember checking my relays a few months ago during another time I was trying to diagnose the problems, and they checked out ok.

Do I need an electrometer (sp?) to test the wiring? Can I have this done at Autozone? I've heard you can, but not sure if its true.

go easy on me. I'll give you whatever information you ask for, if I can provide it.

 

First thing you want to do is check the fuse. If good, unplug the fan switch on the thermo housing. Follow the lower hose to the block and thats the thermo housing. There will be a plug on it with 2 wires. That is the fan switch. Unplug it.

Take a paper clip, unbend it, and stick each end in the holes in the connector you unplugged. Get in the car and turn the key to [II] where all the dash lights come on and fuel system primes. Does the fan turn on?

If yes, the fan switch is bad. Simple fix.

If no, then swap relays with the a/c fan relay in the fusebox and see if that works. (Assuming your A/C fan has no problems).

If still no with swapped known working relays, then you need to test the fan motor. That part I am unsure about. Either that, or there is a wiring problem and you need to test for breaks/shorts in the wiring.

I had a similar problem with my Civic, but I was lazy and just wired the fan to a switch and just turned it on when in traffic in the summer. I also set my CEL to turn on at like 199 F thru the s300 so I knew I would never overheat the motor.

 

^ great thorough instruction..

 

I'll get at it when I have daylight and come back with any questions. I'm pretty sure I've already done this test and I don't think the fan came on... *looks for paperclip*

 

If the motor does not come on with the switch jumped and fuse and relay seemingly good, it's probably a bad motor. The test is to measure the voltage at the motor plug with a voltmeter. (with the jumper in and the key on). Battery voltage present but fan doesn't turn means the motor is bad. Another way to test is to unplug the fan (and possibly remove it from the car) and run a pair of test wires from the car battery direct to the fan.

 

I think this is what I need to do, but I dont have a voltmeter. I've driven it a bit today and its running fine. Getting up to temperature and staying there. But I still don't think the fan is ever coming on.

 

Did you jump the switch? Yes/no

Just because it is up to temperature doesn't mean the fan needs to be cycling on and off. These cars don't create much heat. I worked on a Prelude last summer, bled the cooling system and it took 30 minutes of just idling in 100°F weather for the fans to pop on. Now that kind of surprised me to say the least.

 

Yeah if the car is moving forward at all, there is usually enough air through the radiator that you don't need the fan.

 

so I just hooked the fan directly up to my battery, and....nothing. Looks like I need a new fan.

wheres the best/cheapest place to get a fan? I need to get this fixed ASAP!

-edit- should mention that I checked the fuse and it looked fine. Couldn't check the relay because there isn't one there for my AC (which is removed) that I could swap it with. But now that I've hooked the battery directly up to the fan and it didn't work, I'm going to start by replace the fan

-Double Edit- just called O'Rielly's Auto Parts and they quoted me $44.95 for one with a year warranty. Autozone did the same but didn't mention a warranty. I'll probably just go with the Irish Mafia to make sure I get a warranty. I'm really hoping this fixes the problem.

 

replaced the fan, and it still won't come on. I jumped the sensor at the switch on the thermo housing and the fan came on (the new fan), so I assumed it must be the temperature switch. I bought a new one on the way home from work today ($36 @ Orielly's as opposed to $58 at Honda), brought it home and I didn't have a deep-well socket big enough to remove the old sensor.

Here's the kicker: when I pulled the plug off of the sensor, I noticed that one of the wires wasn't connected. So, how did the fan come on yesterday when I jumped the sensor with a paperclip? Did I break it between then and now? Or am I missing something?

That leads me to my next question: where to I buy that plug? From what I remember, Honda won't sell me just the plug, they'll only sell me the whole harness. Is the only way to get a new plug going to be sourcing one from a junkyard or craigslist engine part-out?