Uh Oh! Problem (again) - Hill Descent Control Fault

[NoCaDiver]

Uhhh:idk:

 

[FSM06]

Keep us posted Dan, I am scratching my head a little trying to figure how they went from the booster to the CHMSL? I know you can't press them, but I would still like to know the fault code. I will say that the CHMSL (center high mount stop lamp) would make sense in a wet or rainy situation where water may be passing the lamp to body seal. Anyway, hope they get it taken care of properly for you at the "stealership"!

FSM

 

[Falcon]

Ummm...

This...
​

View attachment 127


Is NOT

THIS...

Gimmie back my bullets!
​

 

[MagicMtnDan]

Keep us posted Dan, I am scratching my head a little trying to figure how they went from the booster to the CHMSL? I know you can't press them, but I would still like to know the fault code. I will say that the CHMSL (center high mount stop lamp) would make sense in a wet or rainy situation where water may be passing the lamp to body seal. Anyway, hope they get it taken care of properly for you at the "stealership"!

FSM

Final update:

Got the Mean Machine back from the dealership's service department on Friday night. The documents show that they were on the phone with the Ford Hotline discussing the problem (Hill Descent Control Fault error message). Note that they did this the previous two times I took the truck in for this problem. As I reported earlier, the dealership mentioned they were going to check the Raptor's CHMSL (Center High Mounted Stop Light; aka 3rd Brake Light which is mounted atop the upper edge of the rear of the cab).

They checked the CHMSL and "found some corrosion". I mentioned to my Service Advisor that I had heard about Ford trucks having some leak issues in the CHMSL and he said they're well aware of it (we had discussed this the first time I took it in for the HDC Fault error message) and it wasn't leaking.

He told me they replaced the CHMSL and I went in and picked it up. Oil & filter changed (full synthetic); tires rotated; 15,000 mile service (well, that's what the documents say) and CHMSL replaced.

Speculation (mine): I'd guess that when the water that came in through the satellite antenna (which was dripping into and out of the passenger grab handle mounted on the A pilllar) also went into the CHMSL. Now I don't know that water can get into the CHMSL once it gets in through the satellite antenna but perhaps Damon does. My guess is that it can.

I also wonder if I need to ask about having the Raptor's headliner replaced since some water did drip out of the grab handle. I assume that means that when the water leaked in through the satellite antenna some of it could have dripped onto the headliner?

 

[BigJ]

Huh. In one way I'm glad to hear the issues you were having are related; one less thing.

As for the headliner, maybe so. Although if it were me I'd look around very carefully for visual signs of damange first. I'd also try and sniff and see if I smelled mildew or a musty scent. If no to both, I'd probably not worry about it.

 

[MarkT]

My guess is that they were two separate leaks...

Interesting stuff... it sounds like a problem in the CHMSL could have maybe "backfed" the brake light circuit enough (I'm guessing you had your headlights on) to throw the ABS/Hill Descent computer into a fit with a false signal?

I'd like to hear what Damon has to say as well.

(I wouldn't worry about the headliner either unless you have stains and/or a mildew smell as J mentioned)

 

[MagicMtnDan]

it sounds like a problem in the CHMSL could have maybe "backfed" the brake light circuit enough (I'm guessing you had your headlights on) to throw the ABS/Hill Descent computer into a fit with a false signal?

You're right Mark!

I was driving in the rain and following California law by having my headlights on.

More info: The leak from the passenger grab handle only happened early on a couple of times. The dealer was never able to duplicate it (and this was before the TSB was issued on the satellite antenna issue).

 

[MagicMtnDan]

if it were me I'd look around very carefully for visual signs of damange first. I'd also try and sniff and see if I smelled mildew or a musty scent. If no to both, I'd probably not worry about it.

Good points.

My nostrils are open. If I smell something stinky I'll check and make sure it's not me or one of my passengers :mrgreen:

 

[FSM06]

Final update:

Got the Mean Machine back from the dealership's service department on Friday night. The documents show that they were on the phone with the Ford Hotline discussing the problem (Hill Descent Control Fault error message). Note that they did this the previous two times I took the truck in for this problem. As I reported earlier, the dealership mentioned they were going to check the Raptor's CHMSL (Center High Mounted Stop Light; aka 3rd Brake Light which is mounted atop the upper edge of the rear of the cab).

They checked the CHMSL and "found some corrosion". I mentioned to my Service Advisor that I had heard about Ford trucks having some leak issues in the CHMSL and he said they're well aware of it (we had discussed this the first time I took it in for the HDC Fault error message) and it wasn't leaking.

He told me they replaced the CHMSL and I went in and picked it up. Oil & filter changed (full synthetic); tires rotated; 15,000 mile service (well, that's what the documents say) and CHMSL replaced.

Speculation (mine): I'd guess that when the water that came in through the satellite antenna (which was dripping into and out of the passenger grab handle mounted on the A pilllar) also went into the CHMSL. Now I don't know that water can get into the CHMSL once it gets in through the satellite antenna but perhaps Damon does. My guess is that it can.

I also wonder if I need to ask about having the Raptor's headliner replaced since some water did drip out of the grab handle. I assume that means that when the water leaked in through the satellite antenna some of it could have dripped onto the headliner?

Hmmmmm......interesting, not a very concise explanation of the cause and correction of the concern. I spent a little time in the service manual after reading this this morning and tried desperately to tie the CHMSL into the HDC system. So many modules share information over "networks" that it is entirely possible that even though the CHMSL is not directly linked to the ABS module, that it could be getting circuit info there via the Smart Junction Box and/or PCM. The reason I was so interested in the trouble code that was likely set, is that it would lead me to a pinpoint test. Those tests would then help me map where the tech likely had to go to determine the fault.

As far as the water getting to the CHMSL from the Sat antenna, that is not likely. The Sat antenna is in very close proximity to the grab handle and due to the pitch of the truck being a little nose down, I can't see the water getting all the way back there. I also agree that there is likely no damage to your headliner.

Well, only time (and a rain storm) will tell if they got it right. Sure would like to know more details of their findings.

FSM

 

[MagicMtnDan]

Thanks for your time and interest Damon. Don't forget about the brake light failure I had previously (the brake lights were on continuously when I had the Hill Descent Control Fault before). They replaced the brake light switch and the HCU. Something about the ABS system/faults/HDC ties them into the brakes/electrical system. After that problem (brake lights on continuously) I'm sure the CHMSL problem (and my lights being on at the time) had something to do with the latest HDC fault message.

Mark certainly must understand this better than I since he speculated that my lights were on at the time which they were. Keep digging and you'll find the answer - I'm sure of that.

Thanks again