Hill descent control

[IRSmart]

well, as embarrassed as I am to admit it, after almost eleven years with FCA I tried to use my HDC for the first time tonight and failed. Either it works differently on my Power Wagon than it did on my 2015 Cherokee, or I don’t remember how to use it properly. I put the truck in 4LOW, had my seatbelt on, and went to a steep grade. HDC definitely kicked in, but I was not successful in changing the controlled speed, it remained constant at 0.6 mpg. Now, I love the concept of HDC, but c’mon, 0.6 mpg? Gimme a little more speed. It is my understanding that the ERS plus and minus should change the allowed speed, but nothing I did changed the speed. I tried holding the buttons, pressing them quickly, pressing them while the truck was stopped, pressing them during the descent, I even tried pressing the cruise control plus and minus just in case the owners manual got it wrong. Any suggestions on what I was doing wrong? I want to be able to rely on HDC when off-road, but 0.6 mph just won’t cut it.

 

[Low_Sky]

No clues about why yours isn’t working, but it’s the +/- buttons on the transmission shift lever. May need a trip back to the mothership if HDC comes on, but can’t change the speed.


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[IRSmart]

so it sounds like it may be malfunctioning then? i thought i was doing it right, but nothing i would do would change the allowed speed. i tried changing it while sitting still and when the truck was in motion, it didn't make any difference, it would not allow me to change the allowed speed of the HDC. the system did indeed work and keep the truck at 0.6 mph, but i want to be able to use the system in a group and not hold up the line behind me.

 

[pwjouster]

try it in 4H

 

[IRSmart]

HDC does not work at all in 4HI

 

[IRSmart]

Well, I had another opportunity to play with HDC and I’m convinced mine is not functioning correctly. I spent an hour washing my truck tonight, then on the way home decided to play in a construction joke and get all dirty (don’t judge me, I know it is supposed to be the other way around lol). There were some pretty steep grades and large flat tiered fields as they attempt to grade the area for the houses. I saw an opportunity to try HDC out. I can go into 4LOW, unlock the sway bar, lock the axles and actually engage the HDC. The EVIC even says “use + and - on shifter to adjust speed.” The HDC control itself was working when I went down the steep grades. It kept me to a painful 0.6 mph. What I couldn’t do was adjust the max speed using the stalk buttons. I tried pressing them, holding them down, nothing would work. I know those buttons actually work because they correctly control the ERS. Am I doing something wrong, or is my system malfunctioning? I’m going on a trip with a bunch of Jeeps to Rausch Creek in April so I’d like to have this figured out by then. Does anyone know if HDC is available on any other heavy duty truck package, or is it specific to the PW? I have a handful of other heavy duties on my lot but no other PWs, so if it’s on another truck I can compare operation between them (which is what my service department will want to do first if I give it to them anyway).

 

[Low_Sky]

Why not control your speed the old fashioned way, 4LO, low gears and brakes when needed? You’re really not missing much unless you have a loooong steep grade to go down without using your feet. I usually prefer not to use it.

It just pumps the brakes with the ABS motor, doesn’t put any load on the transmission.


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[Grand Mesa]

HDC is offered in the RAM HD 2500 Off Road Package beginning in the 2017 models as of the Fall of 2016.

I use the HDC on the steep (up to 25%) curving downhill grades of the frozen ice and snow packed dirt in the morning and wet grabbing mud before the afternoon roads within the high desert terrain of the Colorado Plateau. Keeps one somewhat confident when mud sliding on the edge of 300 foot sheer drop offs near the Colorado or Green Rivers. Sometimes these roads do become impassable when wet. Been in a situation of which I had to back down one iced over road and it would have been nice if the HDC worked in reverse, but then the old fashioned way of touching the brake does work. Although with much more sliding and white knuckles.

 

[IRSmart]

Why not control your speed the old fashioned way, 4LO, low gears and brakes when needed? You’re really not missing much unless you have a loooong steep grade to go down without using your feet. I usually prefer not to use it.

It just pumps the brakes with the ABS motor, doesn’t put any load on the transmission.


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I can, and I’m familiar with the feature (had it in another FCA product I owned). I’m just not completely ok with the fact that a feature is not working as designed in my 1 month old $63k truck.

 

[IRSmart]

Ok, so we have a 2500 tradesman with the off road package on the lot that I played with. It has the base gauge cluster, but it still showed the speed at 0.6 mph when I engaged HDC. It was operating the exact same way that my PW is operating. It will engage HDC, but it would not let me change the allowed speed past 0.6 mph even though the cluster says to use the shifter stalk to do so. I even tried the cruise buttons because that’s what I used on my Jeep to change the speed, nothing was working. The tradesman and my PW were twins with this issue, which means either I’m doing something wrong, they’re both malfunctioning in the exact same way, or there is some lockout (possibly due to a minimum mileage requirement like launch control on an SRT?) preventing me from changing the speed. Anyone have any additional input?

 

[Grand Mesa]

My Power Wagon cruise control button doesn't want to respond at temperatures below 20 degrees Fahrenheit until I get the cab warmed up to above freezing. Maybe this is the same issue with the HDC.

I know that some Borg Warner transfer cases on a few trucks that I owned wouldn't engage to 4 High when the temperature was below zero degrees Fahrenheit unless I stopped the truck. Low temperatures does impact electronics. Been driving 4x4 vehicles since 1971 and nothing beats mechanical engagement versus electronics. That's why the Power Wagon has a manual transfer case engagement due to it is more reliable under all conditions.

Good luck in finding the issue.

 

[IRSmart]

i don't think it's the buttons because they work with the ERS just fine, they just don't change the HDC like they should. i'm stumped.

 

[67shawnw]

i will try it tomorrow. i have a 2017 with off road and it has it/

 

[Low_Sky]

My Power Wagon cruise control button doesn't want to respond at temperatures below 20 degrees Fahrenheit until I get the cab warmed up to above freezing. Maybe this is the same issue with the HDC.

I know that some Borg Warner transfer cases on a few trucks that I owned wouldn't engage to 4 High when the temperature was below zero degrees Fahrenheit unless I stopped the truck. Low temperatures does impact electronics. Been driving 4x4 vehicles since 1971 and nothing beats mechanical engagement versus electronics. That's why the Power Wagon has a manual transfer case engagement due to it is more reliable under all conditions.

Good luck in finding the issue.

Power wagons get manual transfer cases because there isn’t room on the dash. Our locker and sway bar switches take up the spots used for electronic transfer case on the other trucks. I’m sure if Ram could find a good way to ditch it, they would.


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[Grand Mesa]

Ram did ditch an option on the Power Wagon in order to install an innovative little plastic bean bag sized tray. At least my son's 2014 Ram 2500 diesel 4x4 still has a stick vs a tray. Since the tray location is no longer being used on the Power Wagon it would be a nice spot for the transfer case switch, if one could reach it.

 

[Deviousin10tions]

I've had the same results with my HDC when I was out hunting and decided to play around with it, let me know if you figure something out,

 

[IRSmart]

I've had the same results with my HDC when I was out hunting and decided to play around with it, let me know if you figure something out,

ok, so that's three trucks confirmed that the stalk doesn't change the allowed speed. now if @67shawnw chimes in with the same results we know there's a much larger problem here. i'm not incapable of heel-toe'ing it on the trail, i just don't like that a very cool option on these trucks isn't operating as designed. if i get a slow day at the office i'll take my truck back and have them open a STAR case on it. @ramcares, what are your thoughts on this? Any TSBs or other cases that sound anything like this issue?

 

[Grand Mesa]

I recall on mine that to bump it up from 0.6 mph (1 KM) the transmission has to be in Drive. I put the transfer case into 4 low and push the hill descent control button while stopped with the transmission in Neutral. I have to remember to move the shifter to Drive in order to up the HDC speed, otherwise, pushing the Plus button will not change the speed. From what I have read the issue is still occurring while the vehicle is moving and so I am assuming that it was not coasting in neutral.

 

[18ADR]

ok, so that's three trucks confirmed that the stalk doesn't change the allowed speed. now if @67shawnw chimes in with the same results we know there's a much larger problem here. i'm not incapable of heel-toe'ing it on the trail, i just don't like that a very cool option on these trucks isn't operating as designed. if i get a slow day at the office i'll take my truck back and have them open a STAR case on it. @ramcares, what are your thoughts on this? Any TSBs or other cases that sound anything like this issue?

Hello, I'm new to the forum and was in my new '18 Power Wagon today trying out all of it's functions. Came across the same issue as you. When I put it in 4wheel low, and then turn on HDC, I cannot change the speed in drive over setting 1 (0.6mph), did you have any luck figuring out perhaps what we are doing wrong? thanks in advance.

 

[IRSmart]

Nope, but that’s now three confirmed trucks that this doesn’t work on and I have not yet found a single truck that it DOES work on as designed.