Electric radiator fan runs slow

[gatordp]

I have a 1999 Grand Cherokee Laredo with a 4.0 L six and towing package. About a month ago the electric cooling fan didn't come on one day and the next day, it did not shut off when the car was turned off. I had the relay replaced, and on two days since then about a week apart, the fan would run at a slower speed. It was running, but you couldn't hear the whirring noise it usually makes. The A/C would only cool when I was moving and the engine temp would climb when I was sitting still. During a three week period, this has happened twice, but it has worked fine at all other times.

What could cause the fan to run at a slower speed? If the fan motor was bad, wouldn't it run slow all of the time?

[Bob D.]

Sounds like the relay is not kicking it up into high. The fan operates on two speeds, high and low...high should kick in when the gage temp. gets above 210 deg. or when you turn on the A/C.
It also could be the motor...but as you noted, that's not typical, they usually work or don't work.
Have them check it out where you had the work done... they can jump the relay and see how it acts.