Hood and trunk protection

[ejschultz 10+ year member]

Okay, no one can seem to help me on my impala forum so I'll try here. I've got a 94 caprice and I want to know if it is possible to use the hood/trunk lights to set off the alarm. As far as the hood goes, I've tried negative and positive triggers using the proper wires and have had no luck. I've got a multiplexer on the alarm for use with hood/trunk pins, but I'd like to stay away from that route. Any suggestions will be greatly appreciated.

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[bubbagumper6 5,000+ posts]

You should be able to use the trunk light to set the alarm off. Your alarm should have aux inputs that trigger either when they see 12v or when they see ground. If it's 12v all you have to do is hook it directly to the trunk light wire. If it's ground, then you just need to use the trunk light wire to trigger a relay that connects the wire from the alarm to ground.

 

[ejschultz 10+ year member]

That shouldn't be a problem. I know I've got a positive trigger on the alarm because my interior lights use it. I'd just have to tap the positive trunk wire into that too. As far as the hood goes, I have no clue how to get that light working. Neither wire shows 12 volts or any change in voltage when the hood light is on. Would this require a relay? I could probably set up a relay to act as a negative trigger if this is the case. Any thoughts on this?

 

[bubbagumper6 5,000+ posts]

If you have a hood light, it has to have a positive and negative wire...check the wires again. Not sure why neither showed 12v.

Why don't you want to use pin switches?

 

[ejschultz 10+ year member]

I don't think it looks too clean. Also, I don't really know where to put it on my car. I'd like to use the light if at all possible. Even though I didn't get a voltage reading, I tested every combination of positive and negative triggers with both wires coming off the light. None worked. I also tried the multiplexer wire because that's usually the one you use with pins. That didn't work either. I figure that no matter what, there has to be some current in the line when the light turns on. If i tap into the negative wire on the light and use a relay, there should be enough current going through the wire when the light turns on to activate the relay. Then I could just hook up the relay to ground and the negative trigger of the alarm. That way when the light lights up, the relay is activated and the negative trigger of the alarm can read the ground which should set off the alarm. I haven't thought of that until now. Do you think it would work?

 

[bubbagumper6 5,000+ posts]

When your testing the wires, try putting the negative probe on the chassis of the car, (negative terminal of the battery would be ideal), and probe the others with the positive probe, because like you said, they're HAS to be current going through one of those wires.

If you still can't find it, give what you said a shot. Can't really hurt anything and it wouldn't be hard to hook up.

 

[ejschultz 10+ year member]

I'll test it again tomorrow. If I can't find any voltage for whatever reason, I'll go and get another relay and try that. I'll let you know what happens with it.

 

[Worlddre 5,000+ posts]

//content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif not all things are positve trigger so the trunk light may be negative trigger as well.. If you the light is not showing a change that get a hood pin or ball bearing switch can call it a day.

 

[ejschultz 10+ year member]

I know the trunk is a positive trigger because when I open the trunk and the light comes on I get 12 volts on my multimeter. When the lights are off, I get nothing. The hood is really throwing me for a loop. I was going to attempt to do it with a relay today, but I had other plans pretty much thrown at me. My grandfather finally gave up driving, which he badly needed to do, but now he's been bugging the crap out of me to take him everywhere. It's usually an all day ordeal, which happened to be the case today. Tomorrow it's supposed to rain, so that'll probably hinder me from doing it tomorrow as well.

 

[Worlddre 5,000+ posts]

just use an actual hoodpin....the trunk is supposed to be wired to the multiplex input wire //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[ejschultz 10+ year member]

I've got a mercury switch in the trunk for the trunk lighting. I'm pretty sure I can use a positive trigger for that. When I open the trunk voltage goes from 0 to 12 volts. That would be a positive triggered trunk light. Correct?

 

[Worlddre 5,000+ posts]

yes

 

[ejschultz 10+ year member]

Well, that'll get tapped into my positive trigger then with my dome lights and I'll more than likely end up using a pin for the hood.

 

[ejschultz 10+ year member]

Okay, for those of you who gave me ideas, thanks. What I ended up doing was using 2 relays to simulate hood/trunk pins. It didn't work. Nothing ever does work. Anyways, I tried this:

Supposedly it's worked for others with Caprices/Impalas. The blue wire 6 on H1 that is mentioned is the multiplexer wire which is normally used for hood/trunk pins. I hooked it up exactly as this shows and with the black wire connected instead of the orange wire. Nothing. There are two wires for the trunk and hood (obviously). One is orange (12 volt) and one is black (ground). The orange is constantly hot even when the hood or trunk is closed. The black has to have a small current with the light on. I figured this would send a very small current to the relay when the light kicks on, but I think the current is too small to trigger the relay. Is there an automotive relay that triggers at a very low current? I think it would work if I could get a more sensitive relay. I'm already using the DEI mini relays 8616.

 

[nuugen 10+ year member]

Those lights probably have a roller-ball switch to trigger them when the hood/trunk is lifted..The orange is the constant feed and the black is the ground..When the hood/trunk are lifted beyond a certain angle the roller ball moves and closes the circuit, thereby illuminating the light..You won't really be able to tap into those...To make a clean install, I install my own mercury or roller-ball switch right next to the hood/trunk light, ground one wire and run the other wire to the hood/trunk input on the alarm...Loom the wire and tie it to the oem wire for a nice finished look..You can also look for a current sensor module(DEI makes one), but those are pretty prone to false alarms..

Regular hood pins ****, every car is different on mounting points and they rust/corrode after time and either stop working or give false alarms..