unlock w/dei in 1991 supra neg unlock

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=112925
Printed Date: May 01, 2025 at 12:28 PM

Topic: unlock w/dei in 1991 supra neg unlock

Posted By: g099521
Subject: unlock w/dei in 1991 supra neg unlock
Date Posted: April 05, 2009 at 3:31 PM

Just installed the Python 990 into a 1991 Supra,. Will not unlock the doors using the unlock/disarm feature of the 2-way remote. The alarm has a neg. output available for the lock function, and it works correctly.

However, the unlock ouput from the alarm is positive and the unlock polarity for the car is neg. So I installed a relay to reverse the polarity according to the12volt's "Relays / Converting Polarity" guide. Thereby changing the unlock signal to neg. Will disarm, but no unlock. I still have to use the key.

Ideas?

Replies:

Posted By: Twelvoltz
Date Posted: April 05, 2009 at 4:12 PM

The 990 has low current reversing outputs for door locks. That is the green wire provides a negative when you press lock and a positive when you press unlock, the blue provides a positive when you press lock and a negative when you press unlock. Your 91 Supra should not require any additional relays for locking. Simply hooking the green from the 990 to the GREEN/ YELLOW lock wire in the car and the blue from the 990 to the BLACK/ orange wire in the car should operate the door locks. I recommend using diodes to prevent the positive pulses to the door lock relays, but this probably does not matter in your 91 Supra.

-------------
Installer, IT support, and FFL. I need less hobbies.

Posted By: g099521
Date Posted: April 05, 2009 at 4:56 PM

Many thanks,

The install manual showed the green to be (-) lock (+) unlock and blue to be (+) unlock (-) lock... Did as you said, good call! Much appreciated! I did not test the output before, but everything works as it should now.

Thanks again,
E

Posted By: howie ll
Date Posted: April 06, 2009 at 1:29 AM

Have you tested the vehicle lock/unlock wires to make sure they are correct?