Question: DEI 508D Install - Honda CRZ Forum: Honda CR-Z Hybrid Car Forums

krtashburn · 06-13-2012, 08:00 PM

I apologize if I'm posting this question in the wrong section. I'm having trouble installing a DEI 508D motion detector/alarm trigger to the factory stock alarm. I have done this before successfully to my non-Honda car. I have it receiving constant power and ground and responding to motion. It was my understanding that when motion triggered, the blue and green wires send a negative current and can be connected to a door or hood trigger and when they send the charge, give the car the impression something has been opened and activate the alarm. Example, the hood trigger receiving wire will receive a negative current when the hood releases the button and causes the constant negative flow wire to make contact with the receiving/sensing wire. So, I could hook the green/blue wires to the hood trigger receiving wire and with a negative current burst from motion, POW, alarm. HOWEVER, not only is this not happening, but per my voltage meter, both the green and blue wires are actually sending a CONSTANT negative current and when the device is triggered, sends a DROP in the current by 2 volts. Do I have a manufacturer defected DEI 508D? Or, do I misunderstand how it is supposed to trigger and should be attaching the blue/green elsewhere that someone knows of? When I successfully installed it in my non-Honda vehicle, I simply followed a DIY forum. I'm sorry, but I don't want to intall a Viper and just run the communication plug to that. Thank you!!!

bzrollin · 06-13-2012, 09:56 PM

Red should go to constant 12v
black should go to ground
blue or green should go to any of the triggers. but the 508 is a dual stage sensor, so it really only makes sense to attach one. green is the prewarn, blue is the inner trigger. either should show ground on trigger.

I've always felt the 508d is finicky and seems to change sensitivity with the weather. Good luck.

krtashburn · 06-19-2012, 05:58 PM

Thank you bzrollin. But, I that doesn't cover my question. Please allow me to elaborate.

Mine is currently hooked up to the constant + and ground and responds to movement (lights on). My understanding what allows the 508D to trigger an alarm is that when the device is motion activated, it then suddenly sends a negative current down the blue or green wires, relative to which phase was triggered. This, if connected to a receiving wire that would receive a negative current only by being engaged, such as a door or hood button, would trick the car into thinking that the button has been depressed because the receiving wire has suddenly received a negative charge resulting in the alarm going off because it thinks the door has been opened.

HERE'S WHERE THE PROBLEM LIES. When I hook the green or blue wires to the receiving negative current wire of the door or hood switch, the DEI 508D goes dead, crash, doesn't work. Once removed from the these contacts, it works again. I am aware of the delay between activations. That's not what it is. So, I tested the DEI 508D trigger wires and found something VERY strange that leads me think it is either a manufacturer defect or I am completely wrong about how this device triggers an alarm. Both the green and blue wires are constatly sending out a 12 volt negative current and when the device is motion activated, suddenly drops the current by 2 volts. It's like it's working backwards.

Is my DEI 508D not working correctly or do I misunderstand how it triggers and to what part of my car I should be connecting the green and/or blue wires to?

I have installed a DEI 508D to the factory alarm of my non-Honda by hooking the trigger wires to a fan switch wire, per DIY instructions. Sets the alarm off everytime you put your hand in a rolled down window or put your face in the windshield.

I figured the hood button on my CRZ since the alarm goes off when set and you pop the hood from inside and doesn't go off when I disconnect the hood button. So, trigger wire to the receiving wire on the button (not the constant 12v negative). Would work if the DEI sent a neg burst on activation, but again, seems to be working backwards.

Is the 508D backwards or am I wrong about how it triggers?

If I'm wrong, where do I hook it up? If I'm write, I need to swap it for another one.

Thank you!

bzrollin · 06-19-2012, 07:29 PM

I'm not understanding what you mean by 12 volt negative current. Your meter reads -12V when you have the - lead on the black wire and the + lead on blue or green?

In all honesty it sounds like its a defective 508D. Although, sometimes sensors trigger the alarm by simply creating a drop in voltage, not a true ground signal.

Jwarian · 06-19-2012, 10:07 PM

A negative signal is not possible, the black cable on your battery for example does not carry a negative voltage.

krtashburn · 06-20-2012, 10:34 AM

Thank you bzrollin and Jwarian,

Perhaps my terminology or understanding is off. I believe to complete a DC circuit, you have a positive line and a negative line grounded. Ultimately, all + connections lead to the + battery post and all - connections lead to the - battery post and ground, which are the contacts I'm calling "negative current". Devices that engage and disengage items in the car can do so by connecting and disconnecting either the positive or negative current flow to an item to turn it off. Example, and on/off breaker switch could be on either + or - wires between a battery and an electric motor to turn it on or off.

Litterally, on a CRZ, after testing with a voltage meter, the current the becomes connected or disconnected for the hood button/trigger is what I'm calling the negative current (utlimately leads to the negative battery terminal). If you touch a meter's + terminal to the + terminal of the battery and then touch the - terminal to the constant flow wire on the hood trigger, it reads +12v. If you swap, -12v. If you try to use the batteries - post and touch the constant flow wire it reads 0 because you're not completing a circuit, you're connecting - to -. So, the on/off switch for the hood trigger is on the - wire in my battery to motor example.

The 508D instructions show the trigger wires being - current. Red to a constant +, done. Black to a constant -/ground, done. Assuming the device works by allowing 12v - current/ground to pass through the green/blue wires only when motion activated, if you connect those wires to a receiving wire that also receives 12v -/ground when engaged by a button (hood trigger), that receiving wire and the item it goes to would be fooled into thinking that it has been engaged by usual means of it's button turned on and allowing the -/ground to pass through it's circuitry, but only because the 508D has actually sent the -/ground current through is circuitry. If not activated (by motion), the 508D does not allow that -/ground to pass down the green/blue wires. Litterally, the 508D is a motion activated relay, but to ground/- a circuit, not send + charge to it.

However, the 508D is constantly sending the -/ground current out of the green and blue wires when not activated, constantly completing a circuit. When not motion activated, if I hook my meter's + to the battery + and the meter's - to the green/blue, it reads +12v. When I move and set the device off, it reads +10v. It drops the current. If the device is supposed to work how I've explained, being a motion activated ground/- relay, then this is working completely wrong and the 508D is faulty and I need to swap it soon (Amazon). If I'm wrong about how it works, then please tell me what wire in the CRZ should I be hooking the green (and blue) wires to in order to trigger the factory alarm???

Thank you!!!

bzrollin · 06-20-2012, 08:50 PM

Not sure why you're trying to test it that way. Put the meter - lead on the ground you're using, and the + lead on the green or blue wire. Should read voltage until triggered, then it should go to 0 or somewhere there about. You could also test continuity between those points (should show continuity upon trigger).

krtashburn · 06-27-2012, 02:10 PM

Thanks bzrollin! You answered my question and big thumbs up on the pic!!!

I thought the signal wires would have no current until triggered. You've varified that has current until triggered, then it drops. I'll try attaching the the trigger wires to one of the ones you indicated and see what it does. Still, if to no avail, I'll get another 508D and try again.

The other one I installed (in my other car) was one of the easiest mods I've ever done. I don't know why this one's giving me such a headache.

Thanks again!

Much appreciated.

krtashburn · 02-07-2013, 07:11 PM

I've finally had a chance (and desire) to revisit this project. Here're the problems. It seems the motion sensor trigger wires work the opposite of the logical design. As if I have a factory dud.

The wires that trigger the alarm are sending a constant 12v signal when at rest. When motion triggered, they stop sending a current. This seems like a backwards design. Doors/hood/trunk button wires do not receive constant 12v and then lose their signal when engaged. They do the opposite. They do not receive current when at rest and only when engaged, then receive a 12 volt signal. For this device to work, it needs to actually not send any current when at rest and only when motion triggered, THEN send a 12v current through the wires, fooling the car's brain into thinking that something has engaged (opened) and set of the alarm. It is working backwards from what seems logical. What it has done is when I hook it up to the trunk button wire, it immediately opens the trunk because it is sending out a constant 12v signal. The trunk thinks it's button was pushed. I know that's a bad choice of wire, but it should only send that signal when motion triggered, hence alerting the brain that something has been opened, not constantly send it until motion triggered and then cease the signal.

For those who are familiar with this device (noting I have successfully installed one in another car), would you agree that it seems like my device is working backwards?

THANKS!

06-13-2012, 08:00 PM	#1 (permalink)
krtashburn Newbie Join Date: Jun 2012 Location: Ashburn Posts: 20	Question: DEI 508D Install I apologize if I'm posting this question in the wrong section. I'm having trouble installing a DEI 508D motion detector/alarm trigger to the factory stock alarm. I have done this before successfully to my non-Honda car. I have it receiving constant power and ground and responding to motion. It was my understanding that when motion triggered, the blue and green wires send a negative current and can be connected to a door or hood trigger and when they send the charge, give the car the impression something has been opened and activate the alarm. Example, the hood trigger receiving wire will receive a negative current when the hood releases the button and causes the constant negative flow wire to make contact with the receiving/sensing wire. So, I could hook the green/blue wires to the hood trigger receiving wire and with a negative current burst from motion, POW, alarm. HOWEVER, not only is this not happening, but per my voltage meter, both the green and blue wires are actually sending a CONSTANT negative current and when the device is triggered, sends a DROP in the current by 2 volts. Do I have a manufacturer defected DEI 508D? Or, do I misunderstand how it is supposed to trigger and should be attaching the blue/green elsewhere that someone knows of? When I successfully installed it in my non-Honda vehicle, I simply followed a DIY forum. I'm sorry, but I don't want to intall a Viper and just run the communication plug to that. Thank you!!!

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06-19-2012, 05:58 PM	#3 (permalink)
krtashburn Newbie Join Date: Jun 2012 Location: Ashburn Posts: 20	Thank you bzrollin. But, I that doesn't cover my question. Please allow me to elaborate. Mine is currently hooked up to the constant + and ground and responds to movement (lights on). My understanding what allows the 508D to trigger an alarm is that when the device is motion activated, it then suddenly sends a negative current down the blue or green wires, relative to which phase was triggered. This, if connected to a receiving wire that would receive a negative current only by being engaged, such as a door or hood button, would trick the car into thinking that the button has been depressed because the receiving wire has suddenly received a negative charge resulting in the alarm going off because it thinks the door has been opened. HERE'S WHERE THE PROBLEM LIES. When I hook the green or blue wires to the receiving negative current wire of the door or hood switch, the DEI 508D goes dead, crash, doesn't work. Once removed from the these contacts, it works again. I am aware of the delay between activations. That's not what it is. So, I tested the DEI 508D trigger wires and found something VERY strange that leads me think it is either a manufacturer defect or I am completely wrong about how this device triggers an alarm. Both the green and blue wires are constatly sending out a 12 volt negative current and when the device is motion activated, suddenly drops the current by 2 volts. It's like it's working backwards. Is my DEI 508D not working correctly or do I misunderstand how it triggers and to what part of my car I should be connecting the green and/or blue wires to? I have installed a DEI 508D to the factory alarm of my non-Honda by hooking the trigger wires to a fan switch wire, per DIY instructions. Sets the alarm off everytime you put your hand in a rolled down window or put your face in the windshield. I figured the hood button on my CRZ since the alarm goes off when set and you pop the hood from inside and doesn't go off when I disconnect the hood button. So, trigger wire to the receiving wire on the button (not the constant 12v negative). Would work if the DEI sent a neg burst on activation, but again, seems to be working backwards. Is the 508D backwards or am I wrong about how it triggers? If I'm wrong, where do I hook it up? If I'm write, I need to swap it for another one. Thank you!

06-20-2012, 10:34 AM	#6 (permalink)
krtashburn Newbie Join Date: Jun 2012 Location: Ashburn Posts: 20	Thank you bzrollin and Jwarian, Perhaps my terminology or understanding is off. I believe to complete a DC circuit, you have a positive line and a negative line grounded. Ultimately, all + connections lead to the + battery post and all - connections lead to the - battery post and ground, which are the contacts I'm calling "negative current". Devices that engage and disengage items in the car can do so by connecting and disconnecting either the positive or negative current flow to an item to turn it off. Example, and on/off breaker switch could be on either + or - wires between a battery and an electric motor to turn it on or off. Litterally, on a CRZ, after testing with a voltage meter, the current the becomes connected or disconnected for the hood button/trigger is what I'm calling the negative current (utlimately leads to the negative battery terminal). If you touch a meter's + terminal to the + terminal of the battery and then touch the - terminal to the constant flow wire on the hood trigger, it reads +12v. If you swap, -12v. If you try to use the batteries - post and touch the constant flow wire it reads 0 because you're not completing a circuit, you're connecting - to -. So, the on/off switch for the hood trigger is on the - wire in my battery to motor example. The 508D instructions show the trigger wires being - current. Red to a constant +, done. Black to a constant -/ground, done. Assuming the device works by allowing 12v - current/ground to pass through the green/blue wires only when motion activated, if you connect those wires to a receiving wire that also receives 12v -/ground when engaged by a button (hood trigger), that receiving wire and the item it goes to would be fooled into thinking that it has been engaged by usual means of it's button turned on and allowing the -/ground to pass through it's circuitry, but only because the 508D has actually sent the -/ground current through is circuitry. If not activated (by motion), the 508D does not allow that -/ground to pass down the green/blue wires. Litterally, the 508D is a motion activated relay, but to ground/- a circuit, not send + charge to it. However, the 508D is constantly sending the -/ground current out of the green and blue wires when not activated, constantly completing a circuit. When not motion activated, if I hook my meter's + to the battery + and the meter's - to the green/blue, it reads +12v. When I move and set the device off, it reads +10v. It drops the current. If the device is supposed to work how I've explained, being a motion activated ground/- relay, then this is working completely wrong and the 508D is faulty and I need to swap it soon (Amazon). If I'm wrong about how it works, then please tell me what wire in the CRZ should I be hooking the green (and blue) wires to in order to trigger the factory alarm??? Thank you!!!

06-27-2012, 02:10 PM	#8 (permalink)
krtashburn Newbie Join Date: Jun 2012 Location: Ashburn Posts: 20	Thanks bzrollin! You answered my question and big thumbs up on the pic!!! I thought the signal wires would have no current until triggered. You've varified that has current until triggered, then it drops. I'll try attaching the the trigger wires to one of the ones you indicated and see what it does. Still, if to no avail, I'll get another 508D and try again. The other one I installed (in my other car) was one of the easiest mods I've ever done. I don't know why this one's giving me such a headache. Thanks again! Much appreciated.

02-07-2013, 07:11 PM	#9 (permalink)
krtashburn Newbie Join Date: Jun 2012 Location: Ashburn Posts: 20	I've finally had a chance (and desire) to revisit this project. Here're the problems. It seems the motion sensor trigger wires work the opposite of the logical design. As if I have a factory dud. The wires that trigger the alarm are sending a constant 12v signal when at rest. When motion triggered, they stop sending a current. This seems like a backwards design. Doors/hood/trunk button wires do not receive constant 12v and then lose their signal when engaged. They do the opposite. They do not receive current when at rest and only when engaged, then receive a 12 volt signal. For this device to work, it needs to actually not send any current when at rest and only when motion triggered, THEN send a 12v current through the wires, fooling the car's brain into thinking that something has engaged (opened) and set of the alarm. It is working backwards from what seems logical. What it has done is when I hook it up to the trunk button wire, it immediately opens the trunk because it is sending out a constant 12v signal. The trunk thinks it's button was pushed. I know that's a bad choice of wire, but it should only send that signal when motion triggered, hence alerting the brain that something has been opened, not constantly send it until motion triggered and then cease the signal. For those who are familiar with this device (noting I have successfully installed one in another car), would you agree that it seems like my device is working backwards? THANKS!