FAN/WIPERs slow down with RPMs
 

I have a 1999 Durango 5.2L 4wd automatic with 135,000 miles on it. Out today in the snow I noticed that the fan and wipers slowed down as the RPMs dropped. A guess on my part but would this indicate that the alternator or regulator is going out? Any suggestions on what to look at or what to test.

It could be a few things. The alternator, the battery, or the connections. If you have any corrosion at the batteries that will cause the issues that you are seeing. After that I would get your battery tested. It should be able to handle the load while you are idling at a light or stop sign. The alternator has a hard time keeping up with loads at idle and that is the function that batteries provide outside of starting your car.

Green pretty much said everything I would.

Thanks for the replies. I just bought this Durango about a month ago so no history on the battery and of course no one punches out the little date stickers. I have only eyeballed the battery cables so once the snow stops and it warms up a little I will clean them and see what happens.

Sounds good. Let us know what you find.