Random Engine Fan

[kozakvod]

2013 ISX15 2350 780,000

My engine fan started randomly coming on a couple three weeks ago. The conditions when this has happened, NOT hot (not even 190), NO compressor running at all. Basically none of the things that would normally cause the fan on existed.

Now for it's randomness. The LONGEST it was on was probably 30 mins or so, then it cut off, came on again for maybe 10 seconds, cut off, on again 10 seconds cut off. This was after I had been driving in the morning maybe 15/20 mins. It didn't come on again the entire day until later in the day, was on for maybe 20 seconds, then off.

I spoke to #Snailexpress about this and he did indicate how it could still be the AC side causing it, but also mentioned the Oil Cooler, CAC, etc. As I told him and he agreed that if there was a problem with those it's highly unlikely the fan would come on for just a few seconds. I think he was leaning toward the AC side or an exposed wire engaging the fan randomly. I did try a new solenoid fan switch, that didn't help.

I'm trying to eliminate obvious things. Another buddy said to change the Coolant Temp Sensor that it could be sending a bad signal.

Anyone with any ideas?

[tree98]

I'm pretty sure monitoring insite will tell you what's controlling the fan.

[kozakvod]

(11-21-2022 )tree98 Wrote:  I'm pretty sure monitoring insite will tell you what's controlling the fan.

That was suggested. Although im not sure where to look to see it and I certainly don’t want to be searching for it while driving down the road either. If I knew right where to go to find out that would obviously be helpful if anyone can point me in right direction.

[Rawze]

Intermittent or corroded wiring connection to the A/C high pressure switch is a common cause of this.

[Waterloo]

Agree with Rawze, had the same issue, turned out to be a semi-broken wire to the high pressure switch. It was roughly four or five inches back from the sensor itself under the split loom.