911 sc alarm bypass

[bw50]

1981 911 sc alarm sets itself even though alarm key is in off position
checked resistance at lock- 5 ohms per spec.
removed alarm control box and jumped the two 61 terminals (blue, red blue wires)
still resets itself.
I have trolled the forums any other ideas ?

This is what I found in my archive regarding bypassing the alarm relay socket. I do not remember the origin of the picture. I guess it is somewhere here from the board.



According to this diagram you also should connect the green (GN) and black/white (SW/WS) wires. Color coding seems to be in German.

I hope it helps.

Otto

[bw50]

Otto Thank you I'll give it a try

[86 911 Targa]

Here's another one:




Good luck,

Gerry

Exactly as in the circuit I supplied. Terminals 15/87a connect +12V to the DME relay, activating it. Without that, the car will not start/run.

Thanks for confirming, Gerry!

Otto

[bw50]

30-red 61-blu/red 61-blu MK-brow/wht E/A-gray

Hn- red/wht K1-brown/red 31-brown t- brown/yel 15-black/red 87 a and K1 both appear to go to fuel pump relay

Still trying to find the correct jumps to disable/bypass the alarm system in 81 SC.

Tried jumping 61 to 61
tried jumpin 61 to 61 and k1 to 15

anyone have any ideas ?

The jumper where indeed correctly positioned for this type alarm relay. I think the cause of your problem is somewhere outside the alarm relay.

Check if DME (relay) gets its control voltage or perhaps something simple as a fyel pump relay.

Again, if you installed the correct jumpers, the car should run and the alarm circuit is bypassed.

What happens when you turn the ignition switch?

Otto

[bw50]

When jumped, the car starts and runs, after the alarm is turned off.

When the ignition is turned off, the alarm comes back on in a around 1 min.

So basically it works. It's just that the alarm key doesn't function correctly.

I went to your initial post and looked at the resistor values you measured. The value of 5 ohms seems a bit low to me. Measuring resistance between E/A and 31 at the connector, alarm unit removed/disconnected, should give avalue of 2k7 with the switch ON and 5k4 with the alarm switch OFF. These values may have a tolerance of 10%.

If they would have choosen for these low values as you suggest, a bad terminal contact could easily increase the resistance, misleading the alarm unit regarding the position of the switch.

If you really measure a resistance of just a few Ohm and the same in both switch positions, there could be a short in the wiring in the door/body feed through. If there is no change in resistance when switching the alarm relay, a wiring hort and/or a defective alarm switch could be the cause.

So, please check the resistance values as described and report these values. Then we go to the next step.

Otto