using the dei 528t on an existing alarm?

Howie-

 The diagram posted on 5/9 correctly depicts the application I described in an earlier post; this makes/breaks the ground for existing Horn Relay 2 to control the cycle.  This was the approach using existing relays, just interrupting the latched state of Horn Relay 2.  Yellow is required to be grounded in that application.

Your recommendation, which is more efficient as it eliminates the 2 Horn Relays, must connect power to yellow at the switch output.  As you point out, your recommended application must not tie yellow to ground.

Restoman-

Be extremely careful in wiring which ever application you choose.  Make all the connections except the brown, and test the brown output with a test light or meter before connecting.

Okay gents. I think I have it now (NOT using the original relays). Take a look at the new "lemon fresh" drawing. Did I get it right?

Oh by the way Howie, I did a search on Velleman 100 kit and couldn't find anything. I was able to find a lot of Velleman kits, but none of them had just the 100 in them. Is there another part number for this kit? If it's not too expensive, I might go that route and get rid of even more original parts!!

Thanks again Howie. One last question... The original alarm system is really antiquated and the wiring from the battery to the key just runs under the rear tail panel, exposed to anyone that happens to look under the car!! Back in 1969, no one even heard of a car alarm, but now anyone with a pair of wire cutters can disable the thing in 2 seconds!