remote start 96 chevy astro

i installed a remote start in my 96 chevy astro, the problem is the engine service light would come on whenever i used the remote starter. i found that this only occurs when i have the acc. wire from the alarm system hooked up to the (orange) acc. wire at the ignition harness. i tried using one of the other ignition wires from the remote starter to the vans acc. wire, but it has the same effect. as of now the van will start with the remote with only the starter wire and one ignition wire hooked up. (no tach wire). ihow ever i would like my A/C or heater to come on without having to use the key.i havent been installing for a few years now and am not really familiar with a lot of late 90's vehicles. any suggestions would be greatly apprciated. thank you..

Thanks very much for this info, ill give ti a try and post the results...