Just wanted to say thanks to the forums and members for this thread. Like others, I had an issue where the heater/ac blower on my 2006 Murano either started immediately then quit after about 5 seconds, or took 5 to 10 minutes to start blowing.
After the local Billings, MT dealership replaced the entire blower motor ($220+labor) with no results, I found this thread. The dealership said the next step on their "troubleshooting tree" was to replace an $800 electrical assembly. Hah hah hah. They also tried to claim the motor wasn't covered under my extended Comprehensive Warranty despite being listed along with the relay, but luckily the Nissan National office was able to get me a refund.
I had some trouble finding an online shop which could order the relay for the blower motor, but my local AutoZone got one in 3 days for $37.
It took me about 10 minutes to replace, mostly just to unhook the clips on the fuse panel and work it around to where I could reach the relay. There's a philips head screw which secures part of the dashboard panel which I removed to give me a little extra "wiggle room".
After replacing, it worked like a charm, no problems with the blower which is great news since winter is here.
For those having trouble locating it, find the lever to open your hood. When sitting in the driver's seat it's by your left knee and there's a plastic cover which just pops off. The fuse panel is white, you'll need a small flathead screwdriver to help get it free of the clips and I recommend a flashlight to help see. Once you get the fuse panel free of the clips, work it around so you can see the back and the relay is a small blue cube. There are two, the one on the "top" is for the blower motor. It just pulls right out, and the replacement pushes in, make sure it's snug, then replace the panel in the holding clips and put the screw back in and snap the plastic cover back on.
If that doesn't work then it might be one of the other issues people have mentioned, but for less than $40 and a few minutes work this is a good thing to try before spending a load of cash on something else.
And with all due respect,
zebelkhan, you are not correct in saying that relays "either work or they don't".