Help! My radiator fan wont turn off!

[Tyson Varosyan]

I left the car today after my daily drive in the driveway as usual. The car
is an 87 4kcsq. It is normal for the radiator fan to be on after I leave the
car. The radiator fan control seems to be independent of the key. However,
to my surprise, when I went outside about 5 hours later, the fan was still
buzzing along... I got in the car, the battery was so drained that it needed
a jump.

The damn fan will not turn off no matter what I do. The water temp gauge is
working properly and I topped off the coolant. I also tried disconnecting
and reconnecting the two sensors that it at the hose junction that leads to
the top of the radiator. No luck there ether. In desperation, I unplugged
the fan and went to drive the car around to do some chores. On the highway
it has no issues, but soon as I slow down to city speeds, the engine temp
goes up pretty dang quick. I was left to doing a funny dance of having to
pop my hood and plug/unplug the damn fan every time I got in and out of the
car. I'm in Seattle! Playing under the hood when it raining all the damn
time is not fun!

I'm thinking its got to be a coolant sensor issue. But where is the damn
thing? I found quite a few sensors that tap into the coolant system. Which
controls the infamous fan? Also, could a bad/sticky relay cause the problem?
If so, where is that at?


Tyson Varosyan
Technical Manager, Uptime Technical Solutions LLC.
tyson at up-times.com
www.up-times.com
206-715-TECH (8324)

UpTime/OnTime/AnyTime