SC- 1st Gen (1992-2000)

Making 92-94 SC300/400's "beep" audibly when using the factory keyless entry

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Old 11-10-12, 07:02 PM
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KahnBB6
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Default Making 92-94 SC300/400's "beep" audibly when using the factory keyless entry

As the title of the thread states, I'm on a mission to solve this annoying deficiency in my 1993 SC once and for all. I'm a bit OCD about locking the car because I can never hear whether it locked, nor is there any difference between the sound of it locking and unlocking. I found two existing threads on the subject, posted in one to find answers and found that it had been closed about a day later. Some people have figured this out but I haven't seen any writeup here to explain the process step-by-step. 1995+ SC's have this function from the factory.

Here is the other thread, which at least describes something of a solution but isn't very clear:

https://www.clublexus.com/forums/lex...ess-entry.html

Simply, I don't want to use an aftermarket alarm system, just the factory system and factory remote master key button to trigger. A simple "beep" upon lock or unlock would be enough but making the lights flash at the same time would be a bonus secondary goal. A quick chirp of the horn or piezoelectric speaker would do.

I'm making this thread to invite suggestions and I am also going to post what aftermarket solutions I find to add this functionality in the way I have described. Either way, I will DIY my solution with pictures when I figure out how to actuallly do it.

For the moment, if anyone can suggest a starting point I'd be very appreciative. My guess is to find the hidden transmitter or the on/off button wiring under the dash and begin there.

More to come, but so far I've found this buzzer kit for existing Tacoma keyless entry systems:

http://moerse.com/PRODUCTS/TT_Buzzer/Buzzer.htm

UPDATE: I have just tried this link and cannot find the product listed on the moerse site. I have contacted them to find out if it has been discontinued or if this is simply a site error.

I'm still looking around for anything better or a radio shack method.

Last edited by KahnBB6; 10-17-13 at 02:12 PM. Reason: Updated with info regarding Tacoma beeper module availability
Old 11-12-12, 01:19 AM
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So, update on that module. I've emailed the guy who makes and sells them but I've already reasoned that it triggers from the parking lights on Tacomas because on those 2005-2010's they already flash. They just make no noise. This also explains why on there is a switch on that box to disable the relay and return the system to normal when the use of emergency flashers is desired. So the trigger has to be directly from the remote entry fuse (or the on/off switch under the dash) on our early SC's and getting the lights to flash would require yet another relay.

More research...
Old 11-12-12, 07:11 AM
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Integra2SC
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Good luck keep us informed, I as well have a 93 sc300...
Old 11-12-12, 03:45 PM
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BAD954BOI
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I'm in for results also...
Old 11-12-12, 03:57 PM
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Jos
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You know how the dome light turns off when the button is pushed to lock the doors? I was wondering whether the circuit is opened again when you unlock it?

This way I was wondering whether it's possible to integrate the horn beep to the door lock actuators relay wiring?

Just a thought, not sure whether it's feasible.
Old 11-12-12, 04:08 PM
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1JZPWRD
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I believe we could this to work, if someone had the complete wiring diagram. I would even be happy with the horn one time for lock or something similar. My symptoms with mine, is the keys just up and quit working whatsoever. The keyless part. I replaced the ecu module out of the same year, and the whole unit in the passenger side panel. I also read that you turn the radio on and turn to 94.5 then press the key, you should hear the radio go dim to silent, then release the key trigger, the radio should come back on. This method assures the key is communicating with the ecu. This does work on mine, but the key will still not unlock the doors or lock them.
Old 11-12-12, 04:09 PM
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1JZPWRD
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sorry to get off the actual true problem, but this might be something also could be a problem.
Old 11-12-12, 05:44 PM
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Originally Posted by 1JZPWRD
I believe we could this to work, if someone had the complete wiring diagram. I would even be happy with the horn one time for lock or something similar. My symptoms with mine, is the keys just up and quit working whatsoever. The keyless part. I replaced the ecu module out of the same year, and the whole unit in the passenger side panel. I also read that you turn the radio on and turn to 94.5 then press the key, you should hear the radio go dim to silent, then release the key trigger, the radio should come back on. This method assures the key is communicating with the ecu. This does work on mine, but the key will still not unlock the doors or lock them.
1JZPWRD -- This is good information to throw in because this thread is based upon the idea that your 92-94 keyless entry is already functioning, otherwise an aftermarket alarm system would probably cure all issues. I had a non-functioning master remote key when I bought my SC but I had a Lexus dealer cut and install the new OEM blanks and transmitter I ordered. I have no experience on the correct procedure to code 92-96 wireless keys.

Jos -- I know the function you're describing but my guess is that the factory relay only triggers to shut off the dome light and not to turn it back on for unlocking. It's a good suggestion but it might still be easier to find a connection somewhere under the dash for the trigger.

I'm thinking ahead of myself here but if the relay(s) and buzzer are to be left under the hood I'd run the wires through the same under-dash grommet location I suggested in my 92-94 foglight dash switch thread, which I'll reiterate here when I have the DIY ready.
Old 11-12-12, 06:21 PM
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Jos
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KahnBB6 - Agreed. I was thinking that two relays would be required. One would be the ground (while locking) closing a relay to send a signal to the horn (or aftermarket beep), and the other a positive opening the circuit (while unlocking). I guess I'll have to have a look at a wiring diagram and see. The only other thing I can think to do is purchase an aftermarket horn or noise and run that power from the ECU signal, since it's connected to the keyless.
Old 11-13-12, 02:46 AM
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Jos, I don't think two relays are needed for locking and unlocking functions. Not if the direct circuit is found. What is needed is a relay system intelligent enough to alternate single and double chirps each time the wireless is tripped, hence why the Tacoma box, for $30 seemed like a good starting point... until it became clear that it isn't intelligent at all-- just beeping once or twice in succcesion in accordance with the factory parking lights doing exactly the same thing from the Tacoma's ignition/ECU. We need to recreate a similar circuit.

I'm also curious if 1995-1996 cars just had this function added as a separate subsystem on top off the original keyless entry design. If so it might be possible to copy it or transplant part of it. That's a real long shot but just a thought...

Going from the ECU signal directly might be a good possibility. I'm looking into tthe fuse box or hidden transmitter locations first but if those don't work I can't think of another place to trigger from.
Old 11-13-12, 09:44 AM
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Jos
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I really don't believe that there would be another location that could work seeing as the circuit isn't integrated into all that much.

I'm gonna be tearing mine apart over the weekend to install the stereo, following Raine's write up, so I'll try to find a wiring diagram before hand and see if something can be done.
Old 11-26-12, 02:38 PM
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Yes I need this too! Too often I lock my car walking away just to find it actually unlocked when I return. If we can figure out the beep or lights flashing I would be ecstatic!
Old 11-27-12, 01:53 AM
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^^ Haven't we all? it drives my girlfriend crazy when I always check to see if my car is locked. I'm still going ahead with figuring this out. I've been busy with work and Thanksgiving this last week.

The thing that will be a bit difficult is getting a way for the relay(s) to differentiate between locked and unlocked signals.
Old 01-24-13, 11:37 AM
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Any updates on this? I am extremely interested in this.

I am also struggling with needing to have the key within one foot of the door handle on either side of the car to be able to lock/unlock the door. Not to change the subject but is this normal on a '92? I have been searching the forums and cannot find an answer.
Old 01-24-13, 12:13 PM
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No updates just yet but I have not abandoned this project by any means. I've been preoccupied with work, moving plans with my girl and generally all my car project time has been spent helping my roommate rewire and repair his diesel Merc G-Wagen since he's not good with electrical and I promised him I'd help before I moved.

As to the distance issue, the older 92-97(?) wireless remote systems don't have much range. It sounds like you may need a new battery but you will only gain a few feet of maximum distance. It's just a quirk of the way it was designed.

The lack of beep issue, however, definitely was addressed from 1995+ models. Where I last stopped was trying to identify if I need to find the trigger signal for central locking near the under-dash fuses or at the "hidden" wireless remote circuit elsewhere in the car.

From there it's a matter of getting a relay to trigger the factory horn, the parking lights or a separate piezo buzzer as with the Tacoma buzzer unit I'd mentioned.


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