The previous owner installed an aftermarket alarm system that also included it own "door jam" trigger (see photo)



I think it has a problem with the ground, because, over the past 3 years, the alarm has gone off about 2 times for no reason at all and I traced the problem to the door trigger...jiggle is and it stopped.

NOW whenever the door is shut, the windshield wiper won't work...I open the door and they begin to work....close the door...no work...open the door...they work...you know the rest.

Anyway, I removed the door trigger and found if I ground the wire that is hook to the back of the trigger.... everything works fine....So my question is...if I force the ground on that wire (remove the panel in the rear wheel well, and ground the wire to the frame permantly)...will it hurt anything (battery, alternator etc etc etc).

HELP!! I am very "electrically" challenged....

 

That switch was factory original. Corvettes built after Jan. 73 the plate that holds the switch was grounded. I have found the wire was spot welded to the plate and it breaks off sometimes. You are on the right track ground the plate.

 

If I ground the wire, will it drain the battery? Will it start a fire? What is that switch for? The alarm?

 

Thats the "door ajar" switch

 

Thanks....now....If I ground the wire, will it drain the battery? Will it start a fire?

 

I'm not sure whats going on with your car.I have never heard of that switch grounding the windshield wipers.I cant answer your last question.Check to see if your wiper motor is grounded.

 

Re: the door ajar switch...when I loosen the switch and pull it out of the hole...there's only a white wire...according to the wire diagram, there appears to be a light blue wire as well....could this be the problem?

 

In a '70, that switch is the alarm switch. The door ajar switch is at the front of the door and also lights up the interior lights.

I wouldn't ground that wire. There is a problem with the wiring somewhere. You might get out and then have a bigger problem which will leave you stranded. I'd start by checking the condition of the fuse box. Maybe you can yank the fuse for just the alarm. Also check the condition of the wires around the wiper motor.

 

Sorry I couldnt stay with you last night when it gets late I cant read my crappy 1975 diagram from Bishko Books.
I dont think this is the problem the lt blue is for the door ajar light in the dash .I think your problem is lack of ground at the wiper motor.Since you have a wiring diagram go to the wiper motor and find the 18 black wire that is by itself (term.150)follow that black wire over to a junction of black wires coming from-hood switch,interlock relay,on off switch and a black wire that goes down and grounds at the starter mounting bolt-this wire the one going to the starter is the one that I believe is where your problem is.If its not grounded the wiper motor will "seek" ground through the alarm ground.(This black wire at the starter sometimes ends up on the POS. term. of the solenoid which makes the case of the wiper motor hot.)

EDIT-Z-man thats interesting that your 1970 opt. alarm used the interior light circuit to trigger the alarm.I sorta doubt it though because the most sensitive switch is the door ajar which is the one in the above pic.at the rear of the door.
shafrs3-sorry thats not correct-there again the switch that would sense the slightest door opening would be the one at the back of the door-if you will notice the first click of the door latch will turn off int. light but not the door ajar light.

 

You're right, the switch in the pic is dual function, it lights the door ajar and also trips the alarm if set. I suspect z-man's is the same.

Had to break out my schematic for this one.

I also agree that vetteguy75 needs to check the ground wire by the starter, it is also the ground for the blower motor on a '72. It should have a large ring terminal, mine has been under a 14-20 bolt fastened to the block ahead of the starter. Lack of grounds can cause weird electrical problems.

 

That's what it was!!! had a bad ground to the wiper motor. I forced a ground with an independent wire and she worked perfectly!!! Now to find the break in the ground wire....THANKS!!!

 

The break in the ground wire was under the wrap about 12 inches from the wiper motor on my Corvette. Their was a metal conector and one wire was burnt off maybe from hooking the ground wire at the starter to the + termnal on the starter. Just follow the spade ground wire to the break.

The switch for the alarm before Jan. 73 had three wires and one was the ground. In Jan. 73 GM started using a two prong switch and at that time a black wire was spot welded to the plate and run as the ground.
If the ground is broken the switch can not work correct. The rivets or plate should ground a test light to see if the ground wire is still attached to the plate as you can't see it.