Alan

Did you mess with any of the interior lamps - e.g. remove them all for example?

What heppens when you do what Borland proposed "Simulating the ground at pin 7 would rule out any problems with the wires leading to the lamps" do this - just ground Pin 7 - do the lights come on?

Alan

GMM928

Finally had a few minutes this morning to spend on the car. Neither one of the hatch release pull ***** will operate the rear hatch release motor. When I grounded Pin 7 from the control module, the door lights and under-panel (passenger footwell lights) come on, but the overhead dome lights and rear hatch light do not light...

GMM928

Alan, I didn't remove the interior lamps. A few days prior to removing the old aftermarket alarm system, I did replace the interior festoon bulbs with LED bulbs (one at a time). All lights worked fine then; the problem started when I pulled the old alarm system.

I've now found the wiring diagram online (97-389) and attempted to follow it for the interior lighting system (not great at reading it, though).

As it stands, grounding Pin 7 on my alarm module to chassis ground lights the door panel lights and the CE light. Because the dome and tailgate lights don't light, I guess I must have a break in the br/wt wires leading to the dome and tailgate lights?

Also, because the tailgate motor will not operate using the driver (or passenger) release **** with doors open, I guess my other problem is that I'm not getting a good ground to the alarm control unit?

Thanks again for the help. At some point, maybe I just give up and try to take it to a local shop to sort out...

Mrmerlin

check the hatch motor fuse

GMM928

ok - will do. thanks.

borland

Don't give up yet.

Check the switch position for the lamps that do not light with your temporary jumper between pin 7 and chassis ground. Those 3-position switches can be confusing.

The Alarm Controller just bridges internally it's pin 7 and pin 21. You said you could hear a click when the door was opened, so it is likely working, but ... Check continunity between pin 7 and pin 21 with the door open.

Now for the tailgate motor ground, check for ground at the tailgate switch.... With one of the side doors open, check continunity between tailgate unlocking motor special ground wire (BN/WT) at the unlocking motor.

Now check the tailgate door switch at the Alarm Controller. With the hatch door open, check continunity with chassis ground at Alarm Controller pin 3 (BR/WT).

GMM928

thanks, borland. will try to find time this evening to check the above.

GMM928

Dumb mistake on my part - I had removed wire harness P from the CE board to check briefly, and didn't reconnect it when I grounded Pin 7. That's why the dome and tailgate lights didn't work.

With the harness re-connected, all six interior lights work in auto mode when I bridge Pin 7 of the Alarm module to chassis ground. So, no problems with wiring between my alarm controller and the lights.

As well, the driver's side hatch release **** DOES operate the tailgate unlocking motor (but its a bit finicky; doesn't work every time). Still, when the driver's door is open and the tailgate motor can be operated by the release ****, it seems there must be a good ground. That ground must not be connecting from pin 21 to pin 7.

I have to admit, borland, that I'm not exactly sure which pin on the alarm controller is pin 21. I think it must be one of the br/wt wires entering the controller via the yellow wire harness. I will try to identify pin 21 and bridge it with pin 7; let you know what happens.

Thanks again to all of you for helping me as I stumble through this problem. Frustrating, but great way to learn about the wiring system. And, this is (for sure) a great problem to have vs. the alternatives...

borland

The wiring diagram shows two plugs to the Alarm Controller. Pin 21 is on the other plug, not the same plug with pin 7.

Apparently from your testing results, the driver door pin switch is working to supply the hatch release motor it's ground. You should verify the same for the other door. Once you do this, you would want to verify the same ground signal is wired to pin 21 on the Alarm Controller. If that is the case, then you could concentrate on the Alarm Controller as the repair target.

Otherwise, it is the wiring leading to the Alarm Controller, pin 21. There is also a wire junction shown on the wiring diagram as Junction 23. The guide at the end of the wiring diagrams does not identify the location of Junction 23, but it is likely located under the center console near the Seat Belt Timing Relay.

Instead of bridging pin 21 with pin 7, easier to just check continunity between pin 21 and chassis ground with one of the side doors open.

GMM928

Really helpful, thanks borland. Will keep you posted.

GMM928

Progress.

I pulled the alarm control module and checked for continuity between pins 7 and 21 - nothing. I re-connected the wire harness with pin 7 and grounded pin 21 to chassis ground - again, no interior lights. I then bridged the br/wt wire normally connected to pin 21 (switched ground from door pin) directly to pin 7, and all lights worked perfectly. So, the wiring leading to pin 21 is fine and the wiring from pin 7 to the CE board and the interior lights is fine. I also noted wiring Junction 23 on the diagram, but the wiring seems to be working properly...

It seems there is no bridge between pin 21 and pin 7 in the alarm control module. I'm guess this means I'm in need of a new control module?

On the bright side, this exercise has helped me to learn to read and follow the wiring diagrams for the car (thanks borland, alan, etc.).

borland

Maybe Alan can tell you if your Alarm Controller is easy to repair. I've never opened one up, as my '90 S4 preceeds the integrated alarm system.

GMM928

Lucky for me, 928Intl had a used one in stock from a 1991 at a great price, so I'm covered. Assuming the replacement module solves the problem, I would like to see if mine is repairable. If Alan or someone else is up for repairing it, I'd like to get it sorted and then offer it as a test module for the next guy who has a problem.

Don't want to think about the next step if the replacement module doesn't work...

borland

That's why I'd want to investigate a repair before swapping out what may be a perfectly good part. Are there other alarm functions that can be tested? I know that the diagnostic port can be used to check the Alarm Controller for alarm fault error codes.

GMM928

I own a hammer diagnostic tool, and it didn't detect a fault code. Maybe your software would detect something where the hammer could not...