syc0path

I have an aftermarket alarm in my '88 TA. The alarm includes a output to trigger a trunk or hatch release. The output is a 250mA negative trigger that only works when the car is off or when it's in Park w/ a door open. I know the stock switch will work when the car is on if the parking brake is engaged, but I never use it and I don't wanna have to worry about it sticking. So I'd like to bypass the factory safety lockout, but for the alarm only -- I want the stock switch to still be protected.

I've searched on this and read the tech article, and from what I can tell, it looks like the stock hatch button provides a ground for the hatch release relay when the button is pushed. So it looks like the easiest way to hook this up would be to splice the alarm output into the connection between the stock switch and the hatch release relay -- when the alarm output is activated, that would trigger the relay just as if the stock button had been pressed. Is this correct? And if so, is 250mA enough current to trigger the relay? Where is this relay located on a TA?

Unfortunately, I don't see the factory safety lockout on this diagram. There's some kind of connection between the 12V+ at the fuse box and the relay, but it doesn't explain what it is. If the factory lockout works on the switch, my above method should work. But if the lockout works on the 12V+ going to the relay, it's gonna get more complicated -- I'd have to add a relay to trigger the stock relay. Where would I get power for the 2nd relay? From the cigarette lighter?

syc0path

It seems like this would be a pretty common upgrade... hasn't anybody done this?

firebirdjosh

iTrader: (1)

I just tapped into a wire (no idea which one) at the trunk release switch. Works great. Also, relays require no where near 250mA.

PhLaXuS

My car didn't have the factory lockout (or maybe somone bypassed it before I got the car). If you can post a schemtic of the circuit, it'll be an easy question to answer. Right now, I've no idea how it's set up.

syc0path

Here's the diagram... I had to split it into 2 pieces so it would be small enough but still readable:

syc0path

part2 of the diagram... it goes in the lower right corner of the above pic...

firebirdjosh

iTrader: (1)

Just have your remote ground out the brown wire coming from the release relay (wire 3).

syc0path

Will that bypass the factory safety lockout? It doesn't look like it to me, but then again there doesn't seem to be any indication of where the lockout is.

firebirdjosh

iTrader: (1)

Well the relay's coil goes to 12V+ hot all times, so grounding the other side has to activate the relay.

syc0path

I'm not so sure... see where it says "See fuse block details Cell 11"? It looks like there's some kind of break in the 12V+ from the fuse box there... I'm guessing that's where the lockout is. If nobody knows for sure, I guess I'll just have to experiment... but it seems like somebody would have done this already

NEEDAZ

It looks to me like you need to add the (-) trigger between the Hatch Release Relay and the Release Switch. That will engage the relay any time you use the trunk pop on the remote, and not affect the stock interlock at all. I THINK what you’re looking for (the interlock) is on the yellow wire below the Release Switch then goes off to ground. If the interlock is open, the relay will not engage because there’s no ground on the other side of the switch. If the interlock is closed the relay coil would ground through the Release Switch. Josh, how does yours work? Any interlock problems? FYI, a bosh ‘style’ relay has a coil resistance of 85 ohms for a Icoil of 141ma. Real word you’ll see any where from 70 ohms (171ma) to 90 ohms (133ma). This is at 12Vdc. At 13.5Vdc you can see for 150ma to 192ma. Just for the numbers.

syc0path

That's what I'm hoping, that the interlock is on the ground of the switch. Then I'd only have to splice 1 wire to get it work. Otherwise I have to add a relay and connect it to a suitable power source. Even that wouldn't be too hard, other than having to run additional wires in the dash. And thanx for the #s... again, that means I (hopefully) won't have to use a relay.

I should have time to work on this tomorrow, so for starters I'll ground out the wire and see if that triggers the relay. If that works even when the car is running, I should be ok.

firebirdjosh

iTrader: (1)

The lockout is a switch to ground according to the Chilton manual.

syc0path

Well I finally got around to working on this... the car's been hibernating all winter, so it wasn't exactly high priority. Anyway, my switch wiring doesn't seem to correspond to the diagram. I have 4 wires...

Orange, 12V+ at all times, regardless of key position or gear selection
Brown/white stripe, dead
Grey, 12V when dash lights are on
Brown, dead

I tested the dash switch, and it makes a connection between the orange and brown/white stripe wires when pushed. The other 2 wires must be for illumination.

So I have to provide 12V+ to the brown/white stripe wire to trigger the hatch. And since the orange wire seems to be hot at all times (I didn't actually try it w/ the car running, but I did put the key 2 clicks forward and shift into gear), the lockout must be somewhere on the brown/white stripe wire. So even if I wired up a relay to the - output of my alarm to produce 12V+ directly to the brown/white stripe wire, it still wouldn't override the factory lockout.

Has any1 else run into this? Or do all your cars match the diagram?

syc0path

Well I did some more testing on this last night... I hooked the switch back up, put the key 2 clicks forward, and verified that the hatch will not pop in this position even though there is still 12V+ at the orange wire. That means the factory lockout works on the brown/white stripe wire. I think my next best option is to find the hatch pop relay and try to tap in there. Does anybody know where this is located?

NEEDAZ

Is the orange wire on the coil? Which wire is on the other side of the coil (brown or brown/w)? Looking at the digram that you say isn't right, it looks like the orange wire goes to the coil and the switch. If there is still 12V on one side of the coil, then taking the other side of the coil to grounding (with the alarms (-) trigger) should pop the trunk.

syc0path

I've been working directly at the switch on the dash -- I don't know where the relay is located. I don't see where the orange wire runs to the switch. According to the diagram, the orange wire runs from the fuse to the relay. Then there should be a brown wire that runs from the relay to the switch, and a yellow wire that runs from the switch to ground. So when u press the switch, power runs from the orange wire, thru the relay coil, down the brown wire, thru the switch, and down the yellow wire to ground. That completes the circuit and triggers the relay.

U know, now that I'm looking at this... if the car matched the diagram and u took a voltage measurement at the brown wire, wouldn't u still have 12V+? Wouldn't the voltage go from the orange wire, across the coil, and into the brown wire? U'd still have 12V+, but it wouldn't be a dead short if u grounded it becuz the coil would provide resistance.

If that's the case, then maybe what I need to do is ground the orange wire on my car. I know what I'll do -- I'll test my brown wire for continuity to ground. If there's little resistance, that would indicate that the brown wire is nothing but a ground and pressing the switch simply runs the orange wire to ground -- and that's exactly what I would be doing if I hooked my alarm up to the orange wire.

NEEDAZ

Orange is B+. Don't ground that through the alarm, you'll kill that channel.
B+ comes in the the orange wire, through the coil, then the switch, then that yellow wire must go to ground through what ever the interlock is (I thought the interlock was just to ground the yellow wire with the P/N switch? You will see B+ on the orange wire AND the brown wire (with no current flow you get no voltage drop), until the switch is pressed (no interlock), then the brown wire goes to ground and coil pulls in. See if the brow wire is going to ground when the switch is pressed. If so ground that wire, just like Josh said.
I see if I can find what ever the inter lock is.

syc0path

I experimented w/ this some more last night... remember that I'm working directly at the switch. According to the diagram, the orange wire shouldn't run to the switch. But my car does have an orange wire at the switch, and that's why my car doesn't match the diagram... I was hoping it worked the same and that it didn't match simply becuz the wire colors were different. So I did a continuity check on the brown wire on my car -- if it works the same as the diagram but w/ different color wires, the brown wire should be at ground potential and have close to 0ohm when compared to a ground. It was 89kohms. But just to be sure, I grounded the orange wire anyway. Again, if it works the same as the diagram but w/ different color wires, grounding the orange wire should have triggered the relay. Instead, it blew the courtesy light fuse.

So basically, my car works nothing like the diagram. I've got it figured out, and I'll need to wire it up directly at the relay... doesn't anybody know where the relay is located??

syc0path

Well I kinda figured out where the relay is... after the hatch is open, I can hear it clicking at the back of the car near the hatch motor. So, 1 option would be to run the necessary wiring all the way back there. Considering I just got my car back together after a repaint last summer, I'm not really in the mood to tear it apart again.

The best option would be to find the lockout and hook the alarm output in after the lockout. The lockout must work thru the ignition, becuz the hatch won't pop w/ the ignition on regardless of what gear the car is in.

Does anybody have any ideas how I can find this, what it might look like, where it's located, or anything? I guess I could probe the ignition harness by trial and error, but that would take forever.

syc0path

Well just to be clear, here's a summary of what I've found and where I'm at...

12V+ comes from the fuse box and is always hot. This connects to 1 side of the hatch release switch in the dash

A brown wire w/ a white stripe comes out of the other side of the dash switch and runs thru some sort of ignition lockout -- the hatch switch will not work if the ignition is on, regardless of what gear the car is in. I still have 12V+ from the fuse box.

What I'd like to do is hook up the alarm after the ignition bypass -- the alarm has it's own safety lockout (if the ignition is on, the car must be in park and a door must be open). Of course, the ignition wiring is all bundled under the dash and above the steering column, so I can't follow the brown/wh stripe wire all the way.

So I decided to go to the hatch motor and figure out what wire shows continuity w/ the brown/wh stripe wire in the dash -- then I could find that wire in the driver kickpanel area and make the connection there.

What I found is that the white wire coming out of the relay (w/ a paper clip stuck in it in the pic) shows continuity w/ the brown/wh stripe wire when the ignition is off. The problem is, I can't figure out how. There are only 6 wires running to the front of the car, and I believe I have identified them all.

The yellow and black connect to terminals that are connected together when the hatch is closed... I believe this triggers the hatch motor to close. The orange wire is 12V+ at all times and powers a small light in the cargo area. The red/wh stripe wire is 12V+ at all times and is apparently the power for the hatch motor. The thin black wire grounds to the body, and the thicker black wire connects to what looks like a solenoid on the hatch motor (outlined in red in the 2nd pic). That's the only wire I'm not sure about... it showed ground when I tested it, but I think it has something to do w/ not allowing the motor to trigger when the hatch is open. In any event, it never touches the white wire.

BTW, I thought about the possibility that both the brown/wh stripe wire and the white wire are just grounds and that's why they show continuity. But neither of them show continuity w/ a ground pt on the body.

So at this pt, I could pull the bundle of wires apart and see what the white wire connects to (there's a white wire on the hatch motor itself from the same bundle, so that's probably it). Another idea would be to fool the motor into believing the hatch is still closed and then test the thick black wire to see if it makes any difference. And finally, the last resort would be to run a wire from the alarm (thru a relay to get the correct polarity) all the way to the back of the car.

syc0path

Ok, well I"ve been playing w/ this again... after blowing out the relay by the hatch motor, I realized that I had the wrong relay... I think it has something to do w/ the rear brake light, cuz the hatch works fine even w/ that relay removed from the car. I also found out that if I unplug the big black wire (the 1 I wasn't sure about in my last post) from the hatch motor, the hatch motor doesn't work. While it was unplugged, I hit the hatch button and now I can hear a relay clicking. I assume this must be the relay that triggers the hatch, becuz it only clicks when I hit the switch and it doesn't work if the ignition is on.

Now hears the problem... I can't find this f*ckin relay!! It sounds like it's coming from the pass side of the dash, so I took the hush panel and the little plastic piece above it off. But I still can't see anything... the only other thing I can take off is the dash pad. Or maybe it's coming from behind the radio or something... does anybody know where this relay is before I tear my whole dash apart????

syc0path

Anybody? Can somebody check the manual for me?