Steve Preston <steveophonic@yahoo.com> wrote:
> I've been trying to think of the best possible
> connection point,but the solenoid driver circuit
> really is the best. Has to be a high current 5 volt
> supply. I would imagine they use some type of
> heat-sinked transistor inside the PCM case to drive
> each solenoids,unless the solenoids themselves are
> really light duty. Can't imagine they would be for
> auto use. If they are driven directly by an I.C.,that
> tends to make me nervous.
Yeah, I wouldn't expect the PCM to drive them directly. That's
sort've what I was thinking when I mentioned tying into the solenoid
area. Obviously I'm working off of big assumptions and have no idea
how the system works, but maybe the signal from the PCM is simply
activating some external module, or possibly activating the solenoid
through a relay in the PDC. If that is the case, chances are you
would be tying into 12v instead of 5, but you could be guaranteed of
the higher current capability and you can either use a 12v LED/lamp or
just use a 7805 + heat sink to drop it to 5v for your LED.
BTW, I just did a google search for MDS solenoid and stumbled across
the following page which briefly mentions how some owners have added
an "MDS on" light as well as some other basic MDS info. This is for
the Grand Cherokee, so the PCM pin they mention may not apply to you,
but might be worth taking a look at just in case:
http://www.wkjeeps.com/wk_engines.htm (The MDS info is down near the
bottom of the page, but there is a fragment hyperlink to it near the
top of the page also.)
Along those lines, here's a web site which has a downloadable PDF
version of the '06 Ram FSM: http://tinyurl.com/2tbrmg The '06 Ram has
MDS, so that would have the full wiring diagrams and all that good
stuff. I don't recall what year and model vehicle you are doing
this on, but even if its not a Ram, that info may be helpful to you.
--
-Jon-
.- Jon Steiger -- jon@dakota-truck.net or jon@jonsteiger.com -.
| '96 Kolb Firefly, '96 Suzuki Intruder, Miscellaneous Mopars |
`-------------------------------- http://www.jonsteiger.com --'
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