2008 hyundai accent, keyless/remote start

Chris Luongo wrote:

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This has been on the forums before (like a few years ago), but the people who make the wiring sheets haven't bothered themselves to correct the information.

The BCM in that car sends small ground pulses down the trunk trigger wire after the BCM goes to sleep.



If you diode isolate the wire, all will be well.



Now, only the trunk switch can trigger the alarm. The diode will block the signals from the BCM.

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I hope I'm not hijacking your thread. However, this one was the closest I could find to answering my question.
Issue: Despite connecting ground DIRECTLY to parking brake pinswitch, I STILL get ground (though with ~15-20O ohms resistance) when deactivated. I can physically see (by manually pushing it) the pin switch break ground. The reading on the meter goes from 0 resistance to ~20ohms.
I'm assuming that somewhere in the BCM, it's receiving a resisted ground signal along that parking brake ground wire.
I received the same results hooking it up at the panel. That's why I went directly to the pin switch.
Would hooking a diode up to the original parking brake ground wire isolate the connection to the pin switch so that I only get good ground when it's actually engaged? Would doing so affect another circuit in some unanticipated way?
And just out of curiousity... why do you think it's still providing resisted ground on that wire?
Thanks.
V-O-A

BTW...
I doubt that it matters, but it's a new 2008 Hyundai Accent w/manual transmission.
I've installed a keyless entry system with remote start.
EVERYTHING works flawlessly.
However... the parking brake ground input is designed as a safety precaution. If parking brake is not engaged... no remote start sequence ability.
Problem is, even with that low-level ground signal, it's enough to tell the system that the parking brake is engaged... even when it's not.
I really would like to solve this in order to be as safe as possible.
Thx again.

These posts have been moved to their own topic.

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the12volt • Support the12volt.com

Use a diode in the circuit treated as a door contact exactly as the 1076 and test first,  I've seen this before on a Peugeot. Ie parking brake line, diode with bar AWAY from switch then join your p/brake wire between switch and diode. Is there a warning light on inst. panel, can you get it "clean" from there?

OOPS  1076 shows the BCI end,and I was talking about the SWITCH end. Diode bar should be TOWARDS the switch with the join between switch and diode. SORRY

Thank you for your response.

I decided to work on this yesterday, since there had been no responses to my post.
First, I put on a diode and tested it each direction to determine correct band direction. The parking brake warning light would only continue to function with the band placed toward the parking brake switch.

It's still kinda weird though... putting one inline diode STILL left me with about a 50ohm resisted "ground". Just to satisfy my own curiosity, and afraid that even this was "too much ground", likely to continue to send a false indication to the alarm/remote starter unit... I chained another diode in series with the first and took another reading. Now, I get >100ohm resisted ground.
I tested the original circuit to determine if the brake warning light would continue to work with these diodes inline, by simply applying the opposing end to ground. No problem on the warning light, it still works.
Chaining the two diodes as describe, isolated my alarm/remote starter wire enough that it now indicates properly when the parking brake is activated.
I did not attempt to go to the back of the instrument cluster and take a reading on the warning light itself, as I already had the whole car totally back together, and accessing the parking brake switch directly was the easiest.

I'm still curious... What do you think is causing this??? TWO series connected diodes is the only solution? BTW, I did briefly think of applying a resistor inline, but didn't want to interfere with the signal to the warning light.
Weird.
Thanks,
V-O-A

I would still like you to have measured this at the inst. panel warning light.