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Problems with factory alarm or dome light not working?

Terry Posten

Well-known member
Dec 16, 2003
Davenport, Iowa USA
I have been having some issues with the factory alarm and my dome light won't always come on when I open the drivers door.

I also have an issue with the factory horn that is for the alarm system. Only the headlights flash and the relay on the firewall that drives the horn clicks but the horn does not sound.

First the relay:

I found that the relay was working but the contacts are fried and was not allowing any current to flow. The old A/C relays have the same pinout and plug design and can handle much more current. Perfect fit and now the horn is LOUD!

Now the dome light:

The dome light and flakey alarm operation was due to the drivers side door switch (the one down low on the door jam and covered with the black boot) becoming corroded and very dirty. I removed all 4 of them and used my bench grinder with a wire wheel to clean all the contacts, screws, and metal housing (it gets it's ground through the chassis and screw). I also made sure there was no paint in the screw hole.

Now the dome light works great when you open the door and it fades out perfectly as it should when the doors are shut. And also the alarm system now activates as it should.

So, take 15 minutes and pull all 4 door switches out and clean them with a wire wheel or brush if you are having intermittent issue with the dome light or alarm system. And check out that small horn relay because I think the factory undersized that relay and it burns up.
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