Let me preface this by saying, I have had constant intermittent fan issues for the last 3-4 months. It started out with the car blowing the 50 amp fuse in the engine bay fuse box. I replaced the fuse a few months ago, and had no issues for about 2 months. Then about a month ago, I blew 2 fuses in one day, right after the other. I did some testing, replaced the fan assembly, the low speed fan resistor, and put a new fuse in. The car has been solid up until this last Friday when the high speed fan decided not to come on. When I had the car tuned, Kevin set it for low speed to come on at 188 and high speed to come on at 194. Low speed has been working fine but once the car calls for high speed, the fan completely stops. The problem is, this is very intermittent. It could work fine for a month, then not work, then start working again in the same day. Here is my Sunday update with my latest diagnostics: OK, so let me outline where I am currently at to see if this helps. - I start the car cold, fans are obviously not on. - I turn the a/c on MAX (car still cold), and the fan comes on as it should. - I shut the a/c off, fan shuts off. - With the a/c off, car still cold, I unplug the coolant temp sensor on the intake manifold, fan turns on. - I plug the coolant temp sensor back in, fans shut off. ALL IS NORMAL AT THIS POINT. - Wait for car to get to ~188 deg where the tune calls for the low speed fan to come on, which is DOES. - Low speed fan runs fine until 194 deg where the tune calls for the high speed fan to come on which is DOES NOT and the fan shuts off completely. - At this point I checked the 50 amp fuse in the main engine fuse box and it is NOT blown. LET THE CAR COOL FOR 5 MINUTES. - Fired the car back up at ~188 deg where the low speed fan should come on which it DOES. - 30 seconds later when the car gets to 194 deg when high speed is supposed to come on, it does NOT and the fan shuts off completely. - At this point, turning on the a/c on max does NOT turn the fan on, nor does unplugging the coolant temp sensor. LS1KILR mentioned the a/c compressor might be going south so I tested that as well with the car COLD. - With the car running, I turned the a/c on max, and unplugged the sensor mounted on the a/c line directly underneath my powerpipe. The compressor kicked off. I plugged the sensor back in and audibly heard the compressor kick back on. -With the sensor plugged in, I also jiggled it back and forth, up and down as much as I could to see if there was any sort of continuity issue with that plug which there was NOT. At this point, from my testing, clearly the wiring to the fans is ok because low speed works all the time, and high speed HAS worked for the last 2 weeks, then only worked intermittently over the last 2 days. Someone over on corral suggested it might be the high speed fan relay... Can the high speed fan relay be changed by itself, or do you have to change the whole CCRM. From what I understand, the relays are in the CCRM. Also, if I were to change the CCRM, would my fan settings that my tuner programmed change? Does this have anything to do with my cycling a/c clutch or whirring sound? I just checked the ground wire going to the fan, because from what I have read, both the a/c high pressure switch and the fan run off the same ground. Resistance on 200ohm setting on my multimeter was between 15 and 17 with the fan working. I tested this by turning the car on COLD, turning on the a/c to verify low speed fan was working, unplugged fan clip, and tested resistance on the ground wire. Even though resistance is high (Haynes manual says it shouldn't be higher than 5), I don't understand why the low speed fan would still work since both low and high speed run off the same ground wire. Tomorrow I will test both power lines for low and high speed fans. Also, as mentioned about, during the instances where my high speed fan isnt working, I notice when the a/c is on, the idle fluctuates slightly, there is a slight whirring sound that increases as rpms risem and sometimes the air coming from the vents isnt cold. Not sure if this is related, but it seems to be. If anyone can help with this, I'd really appreciate it, this is very frustrating!!!