New issue for me: HVAC fan will randomly change speeds to stop blowing at all. Already did the $112 blower motor resistor (ouch!) which is actually a big transistor being PWM'd.
Note that I've done 3 TIPM repairs on the truck already, most recently the fuel pump relay bypass.

Found thread: https://dodgeforum.com/forum/4th-gen...3-laramie.html
It mentioned TIPM connector... so now it looks like I might be diving in for TIPM Repair #4.
Page 12-37 of my Chilton book says that power flows from Battery to Blower Relay to Fuse J15 to (10 gauge Dark Blue) to Fan to transistor ("Resistor") to ground.
The thread above says it's on C7..

So now the fun is figuring out which connector is C7 on my 2011... or otherwise where this wire might reside. A 10 Gauge wire should stick out like a sore thumb in the TIPM bucket.
https://f01.justanswer.com/KJMmrtech...ATA_Repair.pdf doesn't show the HVAC fan on C7 for a 2011.

 

Chilton/Haynes are pretty useless for vehicles newer than about 1983..... Started getting WAY more complicated. You really want a factory service manual. Usually can be found for under 50 bucks in PDF format.....

 

I'd love to get my hands on an FSM for the ram, but have no idea where to get/order one?

 

Bishko is the publisher. A search should turn up something. I usually see 'em on ebay, or amazon.

 

Your Chilton manual appears to align with the Mitchell diagram as well. Mopar wiring diagrams are a bit more nebulous than Ford diagrams, but I think "C7" might be the circuit designator (since it also appears as C7 at the blower motor module) and the Dk Blu wire is in connector C6 at the TIPM.

Based on your description of what happens, I think you should start by making sure all of the wire connections are clean and tight and no connections appear to be melted from high temperatures. If you have access to an oscilloscope you could check the PWM signal to make sure it looks like a clean signal when the speed changes. That might require adding a couple of whisker wires to make it easy to scope since you probably can't easily predict when it's going to act up. If you see that the voltage is low but it doesn't appear to be a varying duty cycle square wave but rather a low voltage and you've already verified the connections are all clean and tight, the next most likely culprit would be the relay in the TIPM.

2011 Ram 1500 HVAC wiring


-Rod

 

So the fan stopped working completely no my way to work today.

Pulled the fan connector on my lunch, not melted.

Pulled the TIPM out, not melted.

Got home, put a volt meter on it. 9.5 volts from zero to halfway, then increases to 12.5 volts at full-on. That's using both fan connectors, so power and pulsed ground are both good.

Pull the fan, bring in house. Hook to one of my batteries.... nada, Nothing.

Looks like the fan motor itself died this time. Off to O'Reilly's...

 

Put the new fan in, int he parking lot...issue solved.

 

Gotta love an easy solution.