'72 alarm system problem

[Kurt G.]

After a year or so of procrastination, I finally got around to trouble shooting and repairing my ailing alarm system. Turns out it was the switch. But now I have another problem. When the hood is open the alarm system and horn sound properly. However, when either door is opened the horn only clicks and the door ajar lights on the dash flash. Anyone have any suggestions?

[Terry M.]

Re: '72 alarm system problem

The ground for the switches at the door(s) is missing. The switches are getting a sneak ground through the door adjar circuit. Rig yourself a jumper wire long enough to go from the door switch to a good ground. Put alligator clips (you can get them at your local hardware store, Radio Shack, or big box builder's store) on both ends. Connect one end of the jumper wire to the good ground and the other to the body of the pin switch. I would bet that cures your problem temporarily.

Then you will have to dig for the little ground wire that jumpers from the plate the switch screws into to the birdcage. That is a whole other story, but I have seen pictures of the problem and fix -- I just can't remember where. Maybe someone else will remember.

[Edward J.]

Re: '72 alarm system problem

Kurt The Ground That The Door Switchs Use Is On The Frame Rail By The Alarm Horn .if The Frame Rail Is Rustly, Or The Ground Terminals Is Corroded The Door Switchs Will Not Work, Also Keep In Mind Those Door Pin Switchs Are A Common Problem, Sometimes Need To Be Cleaned With Steel Wool Or Something That Clean The Terminals.

[Harmon C.]

Re: '72 alarm system problem

On the three prong switches I thought one wire was the ground. On two prong switches used after Dec. 72 on 73 Corvettes they had an attached ground wire to the plate.

[Edward J.]

Re: '72 alarm system problem

Lyle, It is a three prong switch, but the ground for the door switchs exits through the rear bluck head to frame where they ground.

the problem more than likely is the switchs not making a good connection. for both doors.

[Harmon C.]

Re: '72 alarm system problem

Check to see that the brass ends are sticking through the round plastic sleeve on the switch. I have seen the ends broken off the brass tang on the wires or pushed back inside the plastic sleeve.