Jump to content

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Horn fuse and alarm


Recommended Posts

I just purchased a 1999 Boxster. The car is in great shape and I love it! The horn is not working so I stopped by a local mechanic. He checked and noticed the fuse was missing. He inserted a new fuse and the car alarm went off. We removed the fuse to stop the noise so I was wondering if this is an easy fix or a bigger electrical issue? Any help or advise would be greatly appreciated. Thank you

Link to comment
Share on other sites

Looked at the workshop manual & it implies that, if there is a fault/sensor tripped when you arm the alarm (picked up in initial 10 second period), it will isolate that sensor & arm the other sensors & lets you know by beeping the horn, turning on the interior light for 2 seconds & double flashing on the alarm LED on the dash.

The sensors monitored are:

1. left door,

2. right door,

3. front hood,

4. rear hood,

5. oddments' tray,

6. convertible top compartment lid,

7. radio,

8. infra red sensor of passenger compartment (with hood closed),

9. alarm horn (removal),

10. activation of the ignition switch,

11. invalid transponder in key in ignition,

12. interruption of voltage to alarm control module.

I am wondering if cycling the fuse in & out might trip the last mentioned sensor (12)?

Try putting the fuse back in & cycling the alarm off & on with your key. If the alarm keeps sounding, then there must be stray electricity somewhere, short circuit or faulty ground, or the alarm control module is faulty. Somehow the alarm isn't isolating the faulty sensor & turning the other sensors on.

Otherwise if, after 10 seconds, you get the abovementioned signals (LED double flashes, etc) then the system is telling you that it has armed the alarm sensors, excluding one or more faulty sensors. Then you can use the process of elimination to check each sensor, by arming the alarm & tripping one sensor at a time to see if it sets the alarm off. I have heard online that the oddments' tray sensor can be temperamental, the tray needs to be pushed down to firmly to activate the microswitch.

Good luck!!

BTW, are you referring to the 15A fuse in the actual alarm control module? (lives in between the two electrical connectors on the module)

Edited by mattatk
Link to comment
Share on other sites

Thanks for the information! Actually it is the 27 fuse I believe. My key head is bad on my remote I wonder if replacing might solve the alarm issue?

Looked at the workshop manual & it implies that, if there is a fault/sensor tripped when you arm the alarm (picked up in initial 10 second period), it will isolate that sensor & arm the other sensors & lets you know by beeping the horn, turning on the interior light for 2 seconds & double flashing on the alarm LED on the dash.

The sensors monitored are:

1. left door,

2. right door,

3. front hood,

4. rear hood,

5. oddments' tray,

6. convertible top compartment lid,

7. radio,

8. infra red sensor of passenger compartment (with hood closed),

9. alarm horn (removal),

10. activation of the ignition switch,

11. invalid transponder in key in ignition,

12. interruption of voltage to alarm control module.

I am wondering if cycling the fuse in & out might trip the last mentioned sensor (12)?

Try putting the fuse back in & cycling the alarm off & on with your key. If the alarm keeps sounding, then there must be stray electricity somewhere, short circuit or faulty ground, or the alarm control module is faulty. Somehow the alarm isn't isolating the faulty sensor & turning the other sensors on.

Otherwise if, after 10 seconds, you get the abovementioned signals (LED double flashes, etc) then the system is telling you that it has armed the alarm sensors, excluding one or more faulty sensors. Then you can use the process of elimination to check each sensor, by arming the alarm & tripping one sensor at a time to see if it sets the alarm off. I have heard online that the oddments' tray sensor can be temperamental, the tray needs to be pushed down to firmly to activate the microswitch.

Good luck!!

BTW, are you referring to the 15A fuse in the actual alarm control module? (lives in between the two electrical connectors on the module)

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.