Replace the fan motor.

If I recall correctly, the fan relay switches the ground contact of the
motor, not the power contact (but I could be wrong).

It's almost always the motors - the brushes plain wear out.

And, they fail intermittently.

Do yourself a favor - get and install a new motor.


"Ivan Cooper" > wrote in message
oups.com...
> So, on my mother's 1997 SC2, the radiator cooling fan won't turn on and
> the car therefore runs too hot if it sits in traffic. It will get to
> over 3/4 and the cooling fan would apparently never turn on.
>
> First, I replaced the Temp Sensor (turned out the old one in there was
> already the brass type and looked fine). No change. The temp readout
> on the dashboard also seems to be working normally.
>
> I checked the fuse and the relay -- both good, no change when I swapped
> them. Tried turning on the AC, still the fan did not start.
>
> So, I thought it was the fan motor. But when I tested the connector to
> the motor, realized no voltage was being sent to the fan. At this
> point, the dashboard temp sensor was reading almost 3/4 and you can
> feel the extra heat from the engine.
>
> Then I tried removing the fan relay and put a jumper wire in its place
> -- suddenly the fan started right up! I confirmed that the relay is
> just not being switched on (checked voltage on the relay connector at
> the fuse/relay box).
>
> Then I put everything back together and put the relay back in place.
> Bam! Suddenly the fan started up with the engine temp gauge reading
> almost 3/4! I am thinking somehow it fixed itself or the connectors
> were corroded in the relay connector, or something.
>
> Stopped and started the car, back to nothing. The car's still hot and
> the fan won't turn on again. Argh! But when I tried bridging the
> relay again, it started right up.
>
> So... I'm pretty sure it's NOT the fuse / relay / fan motor / wiring
> from fusebox to fan / temp-sensor. It might be loose wiring or
> corrosion in/under the fuse box but I'm not sure about taking it apart
> - how hard is that? Or it might be the computer. Maybe it's sometimes
> supposed to get up over 3/4 before switching the fan on -- but I don't
> remember it getting that hot when I used to drive it! Or maybe
> something else.
>
> Oh, one other thing I almost forgot! There is a little one-wire sensor
> (?) in the front of the engine, near the cooling fan. It goes out a
> few inches from the engine and connects with a white plastic
> barrel-style connector a bit smaller than my finger, to a wire which
> goes (somewhere) routed next to the fan power wires. That white
> connector thing used to be attached to a clip on the cooling fan cowl.
> That clip melted or broke in the past, and the plastic connector sat
> right next to the manifold on the engine and got partially melted. I
> disconnected and reconnected it and it still seems to make a
> connection. Perhaps unlikely this is the cause, but as the only thing
> obviously damaged/out of place under the hood, I thought it was worth
> mentioning.
>
> I'm tempted to just put a manual fan switch in Mom's dashboard and be
> done with it. But I'd much rather fix it right if I can figure out
> how, and I wanted to get a second opinion. Thoughts?
>
> -=Ivan
>