View Full Version : radiator fan problem

08-17-2011, 03:41 AM
I am pulling my hair out.
I have a 98 civic and its radiator fan doesn't come on at all. What is important is that it doesn't overheat but gets close when accelerating on hwy or going uphill slowly. It can idle and not heat up.
I replaced the fan switch after jumping the switches wires and the fan came on so the relay, fuse, and fan motor work. Then I boiled the bottom of the switch in water with a candy thermometer and it was within specs. 200 degree F on and 190 degrees F off. That does seem high but anyways, does the engine control module do anything to effect the fan. When I jumped it I used a multimeter probe which has virtually no resistance and the fan switch was at 4 to 5 ohms.
Another piece of information which I'll add is that in May it had a clean emissions test and my mechanic looked puzzled when he showed me the results and one line was almost zero. However there may have been some naphtha in that tank of gas by accident very little though.
Runs fine otherwise and the check engine light doesn't come on
Tomorrow I'm going to heat the car up and try to get a complete circuit on the newly installed switch.

Lx Civic
08-17-2011, 04:08 AM
i had the same problem in my 99 civic with my cooling fans not coming on but they worked. i replaced the radiator fan switch that sit on the thermostat housing and they started working again