I finally got around to fixing my hill descent by replacing the hi-low switch. Having never been able to use hill descent, I am wondering if it is something you switch on and leave on during your off road excursion or do you simply switch it on when confronted with a downhill challenge?

 

When going down a steep section

 

only when going downhill and don't touch the brake. It will modulate the speed based on wheel speed and its noisy with the abs going crazy checking speed. It's a neat function but would definitely be nice if you could adjust the speed like on newer LR vehicles. Oh and you have to be in Low in order to use it and I like to put the gear selector in first to try and take some of the load off the brakes.

 

You can kind of change the speed of the HDC by selecting a different gear while in manual low range while using HDC, if in 1 or 2 it targets a slower speed (7kph?) and if in 3 or 4 its a faster speed (12kph?)

 

Well that would make sense. Did not know that, sometimes 7kph is a hair too fast and 12 would be way to fast. I find I don't use it often as it is but it's nice to have on occasion.

 

Here is the site where I got that information from if you want a deep dive (well, not THAT deep, it's not that complicated) on the HDC system.

https://www.discotd5.com/drive-train/discovery-2-hdc

 

Considering when it came out. Hill Descent was very complicated when our trucks were new. I try to exercise mine weekly, using it to go down a floor at the parking garage at work.

 

Ha, so true. That’s about the only hills we have here in South Jersey.

 

So In short, No. You would not just turn it on for the duration of your off road ride. Only when on a decent.

it’s a good idea to find a safe hill to give the ABS pump some exercise every so often; helps use the valves in the pump.

I had a nasty accident when I first started off roading because I did not fully understand what hill decent was or how it operated. A veteran off roader told me to just push the button and let the truck do the work. (Or that’s what it sounded like)… no bueno
As whowa004 said, touch the brake pedal and it disengages the hill decent program instantly.

I took a new 2020 defender off road for a day, and you can throttle the speed Of the down hill decent with the steering wheel cruise control buttons… pair that with all the cameras & the truck does drive itself like an RC car. VERY VERY impressive.
Defiantly has come a loooong way since that introduction in the Disco

 

I personally think HDC is silly and I've never needed it. It's standard in most new 4wd vehicles that offer an "off road" package. I imagine that most drivers have never used it.