I bought a Viper 5806v keyless entry/alarm for my car recently. My car uses a reverse polarity mechanism for door locks. It is not nessacery to install like this, just shorting the lock/unlock wire to 12v+ will do the job.

I successfully installed the relay for unlock. When pressing the button, the unlock drops to 0v. That is not the case for the lock wire.

They should be the same but i think i mightve fried something, because when i press lock, I get a peak 3.3v+ pulse instead (no noticable damage on pcb). This does not work in the same configuration as the unlock wire. Although it is not working as intended, it is still putting out a signal for locking, so I'm trying to figure out how to use it.

To put it simply, I have a 3v pulse that I need to trigger a 12v source to door lock wire.

So here are my questions

1) When finding a relay, can I use any signal for the switched signal and the control signal has to match the rating (12v in this example)? As in, is there a 3v relay I can use that will still allow a 12v signal to door wire?

2) 3v is not triggering this relay, so what exactly can I do? I've seen a ton of different suggestions, like bjt transistors, diodes, octocouplers, etc but idk what would be best. This is automotive, signal can reach like 14.20Vdc+, and I probably need like 200ma at least to trigger this.

3)Can you please explain exactly why your answer would work?

It's been 10 years since I worked on electronics this in depth, so please forgive


  • \$\begingroup\$ You should probably include schematics (just the sections affected should do). Be sure to show what you have already connected and changed. \$\endgroup\$ – K H Dec 29 '18 at 3:21

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