civerson4

I installed a new stereo yesterday in my early 95 cab (no immobilizer). The DIY's and Pics were very helpful. Everything with the new stereo is working great (CDR 220, Hertz HDP4 amp under seat, Focal component speakers on the door). I removed the Nokia Amp (hi fi stereo option car) and left the plugs under the seat wire tied and bundled together in case (for some odd reason) someone wants to reinstall the Nokia amp in the future.

However, I noticed last night that the interior lights (dome and front trunk) do not come on when the doors are opened (I have checked the light position/switch) and the central locking is not working. The overhead interior light does work when I rotate it forward to the on position.

After searching rennlist and Streather's 993 companion book, I think the issue may have to do with the alarm control module under the passenger seat. I have found passing references to a separate fuse for this module not in the main fuse box, but no more details.

Before I remove the passenger seat and start poking around, can someone help with the fuse position for the alarm module? Any other ideas? Of course, everything went so smoothly with the stereo install that there had to be an issue with something

Thanks in advance.

nine9six

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ToreB

The fuse is on the alarm/door lock control unit itself, between the two connectors.
Cheers,
Tore

civerson4

Thank you.

mathfuzzy

Hey @civerson4 - sorry to bump an old thread, but what turned out to be your problem? I'm having the same symptoms, but my alarm control unit fuse is good. I'm about to pull it out and send it off for testing, but wondering if you found a different problem turned out to be the issue.

civerson4

I think my issue was the fuse on the actual module, but it was a long time ago and can't be sure. Sorry, I can't be more helpful. But I still have the 993 and both my stereo and interior lights are working and have been for years.

mathfuzzy

Thanks man. I was hoping for a different answer, but really appreciate that it was north of seven years ago and that you responded so quickly. I just pulled the seat and the alarm control unit and found the fuse to still be in perfect condition. For posterity, I sprayed contact cleaner on all of the electrical connections and reconnected it...no joy. Now sending the ACU off to a RL'er to be tested.

OP - glad to hear that you still have your 993! (trust me on this, don't get rid of it)

civerson4

Yeah, the 993 is a keeper. 13 years, 75k miles under my ownership. Not ever going to be sold. Still love driving it every chance I get.

mathfuzzy

FINALLY - my central locking is working. So, as Loren from Systems Consulting commented on a different post when I was trying to diagnose the problem, the fact that the fuse was good on the Alarm Control Unit didn't mean that the ACU itself was good. To be fair, I was a little skeptical, thinking that the fuse should do its job and protect the ACU if it was getting a surge of power. Wrong.

Long story short, I yanked out the ACU (since it seemed like the obvious next step...to see if it was good), sent it to Loren, and found out that it was, in fact fried. As in not repairable. Loren shipped a different, rebuilt unit, I just installed it and everything is back to working as it should. Including the overhead dome light, the frunk light, the light over the ignition key, and the DOOR LOCKS. It sounds like the battery died on the prior owner and a quick charger / booster was connected to the battery and over-volted the system.

The Rennlist community comes through again and I'm very grateful. And psyched to have locks and lights that work!