Air conditioning fan

[Chukbacca]

Good morning…
My air conditioning works great…until it doesn’t. After roughly 45 minutes the fan will shut off-but the control is still functioning. I can hear the damper adjust when I turn that control and I feel as though the ambient temp will change if adjusted…45 minutes later (I timed it) the fan turns back on. No codes

Are there likely culprits I should look at first? It’s a 2015 Ram 1500 crew cab 3.6l tradesman

Thanks as always for your kind responses!

 

[Black-Wolf]

Check your Star CAN Bus connectors. There's a small capacitor in each. The thing is - it's extremely difficult to diagnose because the capacitor will read normal (about 3.6 micro-farads I think) - so you'll think it's fine... You have to hold the probes on the capacitor for several minutes. If it changes (goes up) over time (to 3.7, then 3.8, etc), the capacitor is bad. What happens is, as the voltage travels across the capacitor, it builds up a charge... after a bit, the computer detects that the voltage being stored by the cap is too high, and shuts off that circuit. After a bit, the capacitor - with no voltage applied - loses it's out of tolerance condition, and the computer detects that and lets the bus circuit start communicating again.

Here's the link to the parts that could be the issue - top three are the potential problems: 2015 Ram 1500 “Connector Can Buss” - this is the most likely issue though: Star Connector - CAN Buss - that's where the cap is hidden.

They connectors are typically under the dash - you can check this video out for a bit of info: Chrysler/Fiat PowerNet Network

Go to youtube there are tons of videos on the whole issue (and this applies to almost everything weird where a car has a problem that only appears after a set amount of time, then goes away after a set amount of time - with or without a Diagnostic Trouble Code (DTC)).

 

[Chukbacca]

Wow! Thank you for such a thorough reply!

 

[Chukbacca]

Check your Star CAN Bus connectors. There's a small capacitor in each. The thing is - it's extremely difficult to diagnose because the capacitor will read normal (about 3.6 micro-farads I think) - so you'll think it's fine... You have to hold the probes on the capacitor for several minutes. If it changes (goes up) over time (to 3.7, then 3.8, etc), the capacitor is bad. What happens is, as the voltage travels across the capacitor, it builds up a charge... after a bit, the computer detects that the voltage being stored by the cap is too high, and shuts off that circuit. After a bit, the capacitor - with no voltage applied - loses it's out of tolerance condition, and the computer detects that and lets the bus circuit start communicating again.

Here's the link to the parts that could be the issue - top three are the potential problems: 2015 Ram 1500 “Connector Can Buss” - this is the most likely issue though: Star Connector - CAN Buss - that's where the cap is hidden.

They connectors are typically under the dash - you can check this video out for a bit of info: Chrysler/Fiat PowerNet Network

Go to youtube there are tons of videos on the whole issue (and this applies to almost everything weird where a car has a problem that only appears after a set amount of time, then goes away after a set amount of time - with or without a Diagnostic Trouble Code (DTC)).

I am curious…having no experience with can buss…I found it and my memory says there is an open spot…if I were to move the blower to an empty spot, would that potentially alleviate the situation? Or am I thinking about this all wrong?
Thanks again for educating me!

 

[Black-Wolf]

It would not. The different points have different resistors to manage voltage - but, even if the resistors have the same value, you'd have to move both sides in the CAN Bus - and there's no guarantee that the system would accept that. You can try of course - but I can't take any responsibility if you fry your BCM! Of course, if you listen to my wife, I never take responsibility anyway...