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My central lock alarm system does not work

Discussion in 'Automotive Electronics' started by yash01, Feb 26, 2016.

  1. yash01

    yash01 New Member

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  2. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    Perfect. The relay won;t work using Les's schematic.

    Don't use the schematic in post #55.

    If you put the diode across the coil, STOP. Tell me how the diode is connected.

    Disconnect everything that's connected to 87. 87a and 30 on both relays.
    Connect both pins 85 to a source of 12 V. (Alarm power is OK, Lock power is OK)
    Connect orange to pin 86 (-lock) on one relay.
    Connect orange/white (-unlock) to pin 86 on the other relay.

    Set your meter to ohms.
    Connect your meter across pins 30 and 87a across one of the relays. Pick a low resistance range e.g. 200 ohms. It should show ~0 ohms.
    Try to lock/unlock the door.
    Mark the relay that opens, either lock or unlock. The relay marking should correspond to the -lock/-unlock wires that it's connected to.

    Do, the same for the other relay.

    "Relay that Opens" means the resistance goes to +infinity. It might be a +1 or whatever on your meter. Whatever your meter reads when in ohms and the leads are not connected to anything.

    STOP

    edit: Added If you put the diode across the coil rather than using "in".
     
    Last edited: Mar 6, 2016
  3. yash01

    yash01 New Member

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    I have not put diode across the coil

    I have done all the step you have tell me above but still the relay does not energize

    I have set the meter to ohms, I have got the reading 0.1 ohm across the pins 30 and 87a and I have also set it on continuity and have got buzzer sound across the 30 and 87a pins
     
  4. dave

    Dave New Member

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  5. Les Jones

    Les Jones Well-Known Member

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    With the relays still connected as KISS described in post #62 can you connect the meter set to the voltage range with the black (-) meter lead to terminal 86 on the relay that is connected to the lock signal (Orange wire.) and the red meter lead (+) to terminal 85. Note the meter reading. Press the lock button and note if the meter reading changes during the time of the lock pulse and the value of the reading during the lock pulse. Post the results of this test. It could be that the alarm is not capable of driving the relay.

    Les.
     
  6. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    The sound shoud stop briefly if the relay engages when you press lock/unlock.

    You need to make sure the ignition key is out of the ignition too. Ignition on or the accessory position of the ignition switch enabled will usually disable locking.
     
  7. yash01

    yash01 New Member

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    The reading is 0.448v

    I check that, the ignition key is out of the ignition

    I have also try to connect 12v across the 85 pin directly from the battery, but still the relay don't energize when lock/unlock
     
  8. Les Jones

    Les Jones Well-Known Member

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    jash01,
    I have just noticed that both myself and KISS have made a mistake by saying that the lock wire is orange. We should have said orange/black.
    Assuming that you noticed this error and used the orange/black wire for lock.
    Was the meter reading 0.448 volts all of the time or only during the time of the lock pulse ? If it changed what was the reading before and after the lock pulse.

    Les.
     
  9. yash01

    yash01 New Member

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    Yes I have notice it, I have connected orange/black to pin 86


    Its only during the time of the lock pulse that the reading is 0.448v

    Before it was in millivolts
     
  10. Les Jones

    Les Jones Well-Known Member

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    Disconnect the orange/black wire from pin 86 on the relay but leave the black meter lead connected to the end of the orange/black wire. (make sure that it does not short against anything.) Do not change anything else. Press the lock button again and note the readings and post the results. Also can you measure the resistance of the relay coil.

    Les.
     
  11. yash01

    yash01 New Member

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    Its 12.06v during the time of the lock pulse

    The resistance of the coil is 50.2 ohms
     
  12. Les Jones

    Les Jones Well-Known Member

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    Hi yash01,
    It looks like the output signal from the lock / unlock outputs is not enough to drive the relays directly. I will have to design a transistor driver that will provide about 250 mA to drive the relays. Probably Using P channel mosfets such as the IRF9530 would be the simplest solution.

    Les.
     
  13. yash01

    yash01 New Member

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    Don't you think that I must buy a new alarm system ?
     
  14. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    I just find it difficult to believe that the drive signals won;t support an automotive relay. Anything is possible.

    Is there a "specification page" where the relay drive signals are specified? i.e. -500 mA from lock and unlock?

    The tests I suggested were probably a bit "backwards".

    When I asked you to look at continuity between 87a and 30 with nothing connected to 87, 87a and 30: you did get a beep. Upon activation, there should have been a moment of silence.

    If your more "comfortable" with a "beep" use pins 87 and 30. In this case, you will get a beep on lock or unlock.

    ==

    Try to make sure your grounds and +12 is solid. Did you ever make up the LED test light? A diode + LED + 1K resistor?
    I suppose not. the LED has a flat side. The diode has a band. the band and the flat side have to face the same direction. The band side would go to the (-) side of the circuit to light the LED.

    ==

    One suggestion I have is to use a "12 V test light" just to make sure the power and ground that you are using are good. You can buy a 12 V test light or you might be able to make one from the LED/resistor/diode or a #194 lamp. http://vacuumtubes.biz/documents/GE Miniature Lamp Catalog.pdf

    The #194 lamp is very common,. The side markers may use them, so might interior illumination. I have access to a soldering iron. you may not. The #194 will draw about the same current as a relay and you can see it.

    For testing purposes, you can use the virgin, "trunk release" output. It's negative trigger too.

    Some things you can do with a test light is:
    1) Verify that the 12 V and ground are real and not a phantom voltage using the test lamp. it is possible that you have crimped over insulation, for example.
    2) Substitute the lamp/LED for the relay coil

    ==

    The ACC+ signal MAY prevent locking. In my alarm system it was used to enable Valet (someone else parks the car) mode. The Valet switch had to be moved when the car was ON or in Accessory.

    Side input+ and door input-, i think, are use one or the other. You may actually have to use a pin switch. What they don;t tell you is you can likely use the existing switch when you tap into the dome circuit or wire OR the negative trigger from an existing switch.

    I'm not sure what "foot brake" does.
     
  15. Les Jones

    Les Jones Well-Known Member

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    Hi KISS,
    I too find it difficult to believe that the lock and unlock outputs are not capable of driving a relay. From the 0.448 volts measured across the relay coil it looks like the source resistance of the signal is about 1..3K and the short circuit current about 9 mA. I wondered if the output circuit could have been damaged. The only way I could see that this could occur is if the output was a PNP emitter follower and the base collector junction had gone open circuit and wee were just seeing the base drive current through the base emitter junction. I think this is an unlikely explanation as this would be an odd configuration for an output stage. I think these results confirm that the switching is to ground which ties up with the diagram and yash01's answer in post #60 (I think yash01's answer in post 54 must just be a translation problem or he did know what I meant with the phrase "with reference to")
    yash01,
    Is there any information on the alarm that would lead us to the manufacturers website to try to find the manual ?

    Les.
     
  16. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    So, I said, grab the likely unused Window up and see if it works for that. Use something really simple like a test light or LED.

    I expect it to operate an automotive relay. Some alarm modes CAN interfere with lock/unlock.

    Not sure why the brake pedal is in the equation?

    No valet (turn the alarm off) mode that I can see.
     
  17. Les Jones

    Les Jones Well-Known Member

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    Hi yash01,
    Here is a relay driver circuit that should work.


    Relay_driver01.png
    When you are handling the mosfets take static precautions as they are sensitive to static electricity. The metal tab on the mosfet is connected to drain terminal so do not bolt it to metal that is connected to anything else. The mosfets sould not need a heatsink. The resistors and zener diodes are not required for the circuit to function. The zener diodes and R2 and R4 provide protection from transients. R1 and R3 hold the mosfet off if the inputs are not connected.

    Les.
     
  18. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    I'm kinda under the opinion of trying to use something that hasn't been tampered with before (like the window mode) and see if the relay works with the negative trigger,

    +12 to relay coil and the other end of the coil to the negative trigger alarm wire.

    I would also try making a test light: a LED, a diode (1n4001) and a 1K resistor . The flat of the LED goes in the same direction as the band of the diode. The diode protects against reverse polarity.

    If it doesn't work, I'd consider replacing the alarm module.
     
  19. Les Jones

    Les Jones Well-Known Member

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    Hi KISS,
    I agree. It is likely that the same design would have been used on all of the outputs so if that worked driving a relay then it would suggest that the lock and unlock outputs had been damaged. If it was either of us we would have traced the output connections on the alarm PCB to see what the ouput driver was. When I am buying a product I try to download the manuals before I buy it. I also try to find customer reviews of the product. I think yash01 may have given up on solving the problem as he has not posted for a few days.

    Les.
     
  20. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    I think yash01 has a bit more time/daylight or whatever on the weekends.

    We never did get the data as to how much current the -lock and -unlock can sink. e.g -500 mA.

    Your short circuit current calcs indicate to me a bad driver.
     
  21. dablakmark8

    dablakmark8 New Member

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    its like an Isuzu pickup.install one motor in driver door to lock and unlock all the others.
     

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