Landseer

My boys and I continue to sort-out our car electricals.

Most of our remaining issues are with items that are "touched" by the alarm circuit.

We see 12 volts at both leads that attach to each of the hatch release switches.

Our interior lights work on "on all the time mode" but not from manipulation of the door switches. ( but glove compartment light works fine)

Hatch release doesn't work, except once while grazing two wires at the Z plug.

Ignition is keyed so that only the red key works.

Hatch won't accept the long key or turn with either key. I think somebody did a partial re-key.

My guess is the alarm horn is cut.

Bypass of z1 to z6 allowed it to run, but only with an additional jumper across the(new) fuel relay , plus long drawn-out chugging before it catches.

Bypass of z4 to z6 allows instant starts , probably by tripping the alarm relay, whose sole purpose in life seems to be to engage the fuel pump relay, but doesn't remedy hatch problems or door light problems.

Am thinking there is an additional power feed (like F4) shorting inside the alarm box or other relay misbehavior within box.

I respect that the alarm design and execution is effective. But we are beyond that point in time, since other stuff is adulterated and I can't possibly afford to restore the alarm-related bits.

I want to make this a totally non-alarm car. I want the alarm wiring between hatch doors etc GONE. Degrafted, extracted, gone. Am not comfortable with the this complex stuff being only partially bypassed. What do I do?

Alan

Just leave a jumper in place (but I recommend jumpering Z4-Z6) and remove the alarm module - thats all you have to do.

The alarm module has nothing to do with the interior lights or hatch release not functioning - those are seperate projects.

BTW the hatch release needs the interior lights working correctly in door switched mode to operate... so fix the interior lights first - that may be all you need

BTW Z4 is what drives the fuel pump relay (<'85) you need to have ignition feed to Z4 to run.

The stock alarm module drives this high when not alerting by linking Z4-Z6

Pin Z1 is the alternator field circuit which only goes high when the alternator is generating - this is not a really good source for the fuel pump (Z1-Z4) it can work but not well...

Jumping Z1-Z6 will not allow the car to run unless the alarm is working correctly - it will however eliminate the charge monitoring so you won't immediately know if your alternator fails - its not a good idea...

Jumping Z2-Z6 is similarly not a good idea Z6 is ignition power and Z2 is ground - jumping these will cause nasty sparks to fly... I suspect you did not actually jumper these 2 - the car certainly would not be happy...

Since this plug is 6 pins and most of the rest are 8 pins the labelling of pin positions sometimes gets confusing...

Folks don't go jumping connections unless you know what they do before you start...it can get messy - in many of these cases there are no fuses to protect you...

Alan

Landseer

I needed to take a day or so. Back now.

Yes, I meant Z4-to Z6, and I've fixed that in the original post. Got that from the alarm description in the CD electical troubleshooting guides for this specific MY/Market car. It also mentions Z1 to Z6, but I think it refers to that as the solution to bypass the non-USA version of the 84 alarm, which I didn't catch originally. Am not *****-nilly connecting wires. Close, though.


Thanks for taking a look at this. I appreciate your patience and the time you take on this board trying to help those of us that are electrically challenged, ok, in my case electrically devoid.

Landseer

deleted duplicate

SteveG

Alan: What is the procedure to disable the '85 alarm? I hope it is this simple. TIA.

Alan

For '85 its not quite so simple to do - you need to link Central Electric Pins B23-F25 and unplug the alarm module. Or you can unplug the alarm module and link Pins 1-3 on the alarm module connector (These are the 15 & 87a terminals).

Alan

SteveG

Thanks Alan. For some reason my blue "√"

sometimes doesn't show on the message list, and I couldn't find the thread.

Avve

Hi Alan, is it the same procedure to remove the alarm on a 1986 16 v Euro 928s, as on the '85 you described???
Thanks
Avve/Sweden

leperboy

My experience: I believed this was correct, and jumping 15 to 87A did not disable the alarm. It disabled the horn, but I just got flashing dash lights and no ignition.

In my search of Rennlist, I could never find anyone who successfully disabled the alarm by jumping 15 to 87A, just references to people saying they thought it worked.

Matt

dprantl

I can say that removing the alarm box/relay and jumping pins 15 and 87a *definitely* worked on my US '86. It does not make sense for this not to work, because you are physically removing the alarm and hot-wiring the circuit that the alarm would otherwise cut off (the fuel pump).

Dan
'86 928S 5-spd w/LSD

Avve

Hmm, great note, Dan, 'cause I think the RoW and the US cars had the same alarm wiring in 1986! Back to the garage, then...
Avve
building a 1986 Euro 16v 928 racer

Alan

Matt - for a stock configuration it always works - probably you didn't do it right...

You must remove the alarm and link either of the indicated terminal sets. Removing the alarm elimnates the alarm horn & lighting alerts if you have it (optional). Linking 15 & 87a completes the only part of the circuit that disables the engine.

before or after you do it - veriify you see ~12v on 15 when the ignition is on... creative wiring "adjustments" are common on alarms - I don't know why since nobody seems to have any idea what they are doing....

Avve - ROW 86 is the same as the 85 described above.

Alan

leperboy

You're right. After installing my stereo tonight, I tried jumping 15 to 87A again, and it worked fine tonight. I think I might have had a low battery the last time.

So, yes, you can delete the alarm by jumping 15 and 87A on the alarm connector behind the glove box in an 86.

Matt

Stan.Shaw@Excell.Net

I am looking for the process to disable the alarm on my 90 GT. Any help appreciated... Alan?

Yesterday it wouldn't start, but there was a smell of fuel when it was cranked. Cycling the driver door lock apparently was the solution, as it started afterwards.

A couple of weeks ago, apparently after the battery was disconnected, it wouldn't even crank, until the driver's door lock was cycled.

I have seen it blinking its' lights in the past when parked, so I presume the alarm was unhappy.

Alarm, don't need it, don't want it

Alan

Stan on a '90: Q12 & N11

Alan