1988 porsche 944 horn relay alarm

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Forum Name: Vehicle Wiring Information & File Requests
Forum Discription: Request Car Alarm, Car Stereo, Cruise Control, Remote Starter, Navigation, Mobile Video, and Other Vehicle Specific Wiring Info, Manuals, Tech Tips
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=131764
Printed Date: May 15, 2025 at 9:05 AM

Topic: 1988 porsche 944 horn relay alarm

Posted By: moostee
Subject: 1988 porsche 944 horn relay alarm
Date Posted: July 07, 2012 at 12:00 PM

Great website with great information.

Installing a Audiovox AA925 in a Porsche 944 N/A. Everything connected correctly and working. Just trying to get the correct connection for the horn for an audible confirm of alarm.

I see in the wiring diagram on this site to find the BLACK / YELLOW wire to the horn relay in the fuse box.

Horn Wire

BLACK / YELLOW

Relay in Fuse Panel

I know the right relay (G13) however I cannot distinguish whick BLACK / YELLOW wire from the bottom (6 matching wires) is for the horn. Any ideas how to identify which is the correct wire?

Replies:

Posted By: howie ll
Date Posted: July 07, 2012 at 5:24 PM

Try grounding each through a 12Volt bulb test light.
Or look for that wire colour in the steering column loom.
Good luck getting access there though if the left hand drive version is anything like the right hand drive.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Posted By: howie ll
Date Posted: July 07, 2012 at 5:30 PM

Actually the BLACK / YELLOW is pos (+) probably won't work with the A/Vox, look for a BROWN / white at the same relay location and ground it to test.
You won't do any harm, BROWN / white is a switched to ground circuit on German cars, all you might do is bring on the dome lights or the parking brake icon if you ground the wrong wire.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.