Can someone help me with this. I put a new head timing belts and all on my 95 Accord LX all back together cranks right up but now as soon as i turn car off one fan comes on and stays on. Anyone had this problem before?

 

There's a fan-switch located in the hose nozzle where the upper radiator hose connects to the head. That switch is responsible for switching the fan after you turn off the engine. Check the electrical connections. Check especially whether you've done something to short those 2 wires together. (Pinch em when bolting it back together?)

Then check to see whether you have bled all the air out of the cooling system. Hondas really don't like air pockets in there (this is one of the reasons).

1) If you start the engine cold, turn off after 90 seconds (not long enough to heat up), does the fan run after? If so, maybe it's a bad fan switch but still do test #2.

2) If you unplug that sensor, does the fan still run after? If so, then I'd rather suspect the fan-timer module.

 

if i unplug the sensor on the front of motor it cuts the fan off but i can turn ignition on not start and back off and fan will come on regardless of hot or cold. and i bled the system

 

I'm confused, not hard to do.

So if you turn the car to on and then off, the "one fan" runs? Please confirm which fan (dirver or pass side).

 

pass. side turns on

 

if i leave it unplugged for a while it itll stay off when i plug sensor back in

 

Sounds like a bad switch ("sensor" in that hose nozzle). It's stuck in the "on" position forever.

The fan timer is supposed to turn OFF the fan, even when that switch is stuck "on". Sounds like that's working the way it should.

 

Hello, JimBlake. Hope things are going well for you and yours.

I think I have the same problem as the OP.

This evening at around 11 pm I happened to walk by our attached-garage door and heard a whirring sound. I investigated and, sure enough, the car's radiator fan was on.

The car had not run since about 4 pm when my wife returned home from errands, so the fan was on for about 7 hours.

I disconnected the neg cable from the battery and the fan, of course, stopped. I then immediately re-connected the cable and the fan did not come back on.

You seem well versed in this problem. Is the switch ("sensor") you are referring to the one that the yellow arrow is pointing to in the following photo?



If not, where is it?

If the problem is in the fan timer, where is that located and what does it look like?

I wasn't able to do any testing tonight because it's so late. I've put our auto battery-charger on the battery to bring it back up to snuff overnight.

Thanks, Jim.

 

Poorman's probably better since he has actually owned Accords with this fan-control scheme. (Also, I can't see the photos through the firewall at work)

There's 2 fan switches. One in the thermostat housing (lower radiator hose) is responsible for switching BOTH fans while the engine is running. The one in the upper hose nozzle is responsible for switching only one fan after turning off the engine. The fan timer is responsible for deciding which switch is "in control" and also for switching off the fan 20-30 minutes after turning off the key just in case the switch sticks closed.

Sound to me like your fan switch in the upper radiator hose nozzle has stuck closed. But for it to run the fan for hours, the fan timer isn't doing it's job either. Fan timer module might have flaked out a long time ago but you didn't know until the fan switch stuck closed. I think the fan timer module is buried under the dash someplace near the glovebox.

 

Thanks, Jim.

This morning the battery was fully charged as I expected.

First I connected the neg cable to the battery and the fan did not turn on.

I then disconnected the cable from the fan switch on the nozzle where the rad hose attaches to the head. I then checked the two terminals in the swich for resistance and continuity. There was infinite resistance and no continuity. Situation normal on a cold engine.

I then reconnected the cable to the switch.

Then I removed the still-original fan relay inside the fuse box and struck it a few times with the handle of a screw driver just for the H of it.

I then started the car and the fan still did not come on, which is normal for a cold engine.

I drove the car around for a bit to warm up the coolant and the needle on the engine temp gauge rose normally to about mid-scale. I then drove back home and let the car idle in the driveway until the fan came on. It ran for maybe a minute or so and then, to my surprise, shut off. I ran the car for some time longer and the cycle repeated itself several times normally. The needle on the temp gauge moved only very slightly around mid scale and never rose above that. Situation normal.

I then drove the car into the garage and turned the engine off. The fan did not come on again thereafter as I monitored the car for at least a couple of hours.

Well, whatever malfunction that happened last night has not repeated itself. If the contacts between the cable and switch were not good, or if the switch was failed "open", I would have expected the fan to never come on. If the switch faild "closed", I would have expected the fan to run forever, at least when the ignition was on.

I just love intermittent problems, don't you? I'm very suspicious of problems that seem to miraculously fix themselves. I always expect the problem to reappear at an inopportune time such as while stuck in heavy traffic on a bridge. I suppose that as long as the problem is the fan coming on and staying on, that's OK as long as the engine is running. If it happens when the car is not running in the middle of a cold winter's night, that won't be very good for the battery.

Thanks again, Jim.