Adding Power Running Boards to Non-Factory Equipped Model

[baggedlvintegra]

So I started this thread on the CadillacForums but it doesn't get as much traffic as over here so I figured I post and get your thoughts.

So I'm wanting to add the clean look of the powered running boards to my Escalade that came from the factory with fixed steps. I've tried to do some digging and haven't come up with a definitive answer just yet, and from talking to serge I'm trying to figure out a possible solution.

The attached PDF ( http://www.cadillacforums.com/forum...oards-non-factory-power-running-board-pdf.pdf ) is the wiring schematic for the power running boards. My interpretation of the schematic is as follows:

The big box on the left is the power running board control module, which I would have for the conversion. It appears the majority of the wires go between the boards and the module itself, a good thing becauase they will co-exist together.

The multifunction switch and wire under the dash (for the switch to disable/enable them) should be no problem as those would be provided with the conversion as well.

In my eyes only 3 wires exit the module
1) Wire #2 - blk (left rear of engine compartment) for ground - simple just ground the wire to my vehicle
2) Wire #5 - red/blk (underhood fuse box, hot at all times) - simple, run the wire to a permanent power source with an inline relay / switch
3) Wire # H - dk grn (computer data lines system) - the potential problem child. I am not sure if all models are equipped with a "computer data line system" wire that runs from the fuse box into the ECM or if that is a special feature for factory equipped power running board models.

Obviously from the diagram you can determine that Wire # H is what controls the boards and tells them when to open and close. I feel like this might be the biggest hurdle because if the "computer data line system" wire is specific to the factory equipped model than I would have no way to control when the boards open / close.

***FOLLOW ON RESEARCH YIELDED***
found the install instructions for the AMP steps, havent had time to completely digest them yet but atleast it list all the locations and colors of the "trigger wires" it would take to get these wired up...the forum says the document is too large to upload so I'll have to compress it later

So after pondering over this some more, and reading some posts on another forum I found in a google search, I'm starting to think this is not feasible

While the power assist control module is in control of the boards operation, the signal for that operation purely comes from the BCM via the Wire #H "computer data lines system". According to this statement in another forum:

"They are controlled by a assist step control module that has sole control over operations. The bcm and IPC are also programmed specifically for this option bc they also play a role in operation. The turn signal switch is also different because it has a disable switch built into it that communicates on or off the the step assist control module.

This module ties into the databus.

You cant enable the option unfortunately because it was never a factory option on the trucks. You cant flash the truck bcm for a escalade suv because the turn signals will quit functioning correctly.

Tech 2 cant enable it anyways even on suv that is something that has to be done through TIS OE programming software. "

So the BCM signals the control module to perform the specified function. On non-factory equipped models the BCM does not have the capability to do so thus there is no way to signal the control module for action.

I was thinking it may still be possible using the wiring sequence from the AMP power steps BUT you would only have 1 wire coming out of the control module and would have to tie it to 4 seperate wires running to pass door open, pass door close, driver door open, driver door close and there would be no way to regulate it because the "signal" would just be power, therefore it wouldnt know whether its to open close do a flip or roll over lol

I hate to say it but this may be chaulked up as a loss : (

 

[yates ™]

Is wire H a regular braided wire or a data wire? What all is in the box? I assume another module that must communicate to the ECM via the H wire?

 

[baggedlvintegra]

Is wire H a regular braided wire or a data wire? What all is in the box? I assume another module that must communicate to the ECM via the H wire?

Good questions man, and I have the exact same. Unfortunately all I have is the schematic attached and don't have any physical parts to examine to really have a better insight. Although the schematic doesn't call it out I'm almost willing to bet its a data wire since it says "computer data lines system"

 

[yates ™]

I assume it has a motor in there which in theory could be hooked to a relay using a wire to the door trigger thus by passing the the other electronics in the box. Just a thought.

 

[baggedlvintegra]

I assume it has a motor in there which in theory could be hooked to a relay using a wire to the door trigger thus by passing the the other electronics in the box. Just a thought.

I was trying to think of a way to hard wire myself to work as you suggest, but I just can't see any way to make it work because the module really regulates the open / close functionality through the data wire signal, in that the module holds the power and just distributes the signal to the function. meaning the boards aren't powered directly and then manipulated, so I couldn't go around the module I don't think.

tho I am here seeking help and I'm not against any out of the box ideas

 

[yates ™]

The relay would provide the power, the only problem I see with that is that it would cause constant power when the signal is applied, maybe need to be a multiple relay system.

 

[baggedlvintegra]

so to be honest I don't understand relays enough to know what I could make them do, but would the following (an extension of what you stated earlier) work:

the boards have 2 functions, open and close. They have a power wire that controls open and power wire that controls close. all is simply grounded.

from the AMP power steps I know which wires to tap for door open and door close in the factory harness

could I simply ground the boards, run a permanent hot to a relay, then have a trigger wire off that relay that would only apply power when it gets the signal from the tapped factory wire?

*EDIT* just saw your post...I get your point about constant power, in another thread that was talked about in that the motors dont have "stops" so the signal would maintain power and keep trying to open the boards even though they would be open, burning up the motors right? the same for closed as well.....people on the other thread talked about "timed relays" saying they would cut all power after XX amount of seconds

 

[yates ™]

Timed relays could work. Assuming that the steps have a stop you wouldn't need a relay or motor to keep them down just to go up and stay up, if that makes sense.

 

[baggedlvintegra]

Timed relays could work. Assuming that the steps have a stop you wouldn't need a relay or motor to keep them down just to go up and stay up, if that makes sense.

kind of...obviously the steps can only open so far, but the motors would still be powered and trying to force them "more open" which would lead to them burning up. The statement on the other forum was to have the relay timed for the amount of time it takes the steps to fully open so once the trigger supplies the power to open it would cut off once they were fully deployed. same for them closing.

so what I am thinking is I would need 4 timed relays, one for each side up and one for each side down.....hmmmmm

do you know enough about relays to know how the "trigger" works. Meaning the relay would have constant power and the factory wire tapped would just be a signal to release that power, you don't think it would affect anything on the oem wire side of its operations do you??? that question geared to this statement on the other thread
"You need to diode isolate the door pin's when you do it. If not the back feed 12v through the relay coil to the door pin wire will **** off the BCM. "

 

[yates ™]

do you know enough about relays to know how the "trigger" works. Meaning the relay would have constant power and the factory wire tapped would just be a signal to release that power, you don't think it would affect anything on the oem wire side of its operations do you???

You have it correct.