73 Rear Door Ajar/Alarm Switch Correct Replacement Question

[Jimmy P.]

I am trying to replace my rear door ajar/alarm switches on my 73. Both of the switches are non-functional. The one on the right side is missing, I assume it is down in the frame. The one on the left is rusted, held on with two small flat head screws, and the pin is smashed in. I removed both of the wheel well inner access panels on both sides. The right side just had two wires (no red) present that were broken off on the ends. I'm sure the switch is down in the frame. On the left side I found the switch still present. After removing the rusted screws I did pull the switch back through the TINY hole. It was still attached to the backing plate. It had two wires a light blue and a white/tan colored wire. There was also a third Red wire attached to the mounting plate. While pulling the wires off, the red wire broke free from the plate. The other two wires were plugged in with slide on clips. After removing the wires the plate fell down in the frame. When searching the vendors catalogs for the correct 73 switch I didn't see one that had the same type of end that lets the wires slide on. The switch they list for 73 doesn't look like mine. Also, none of the mount plates had anything where the Red wire would attach. BTW, the # 3 body mounts were in pretty good shape considering. So I sprayed them with PB Blaster/ Rust Inhibitor after cleaning out the area. Also, in the parts searching process I noticed two stick on pads that go on the doors. They only suggest them to be used up to 72. But my doors have a square area that looks like a pad was there at one time. My jams are still in original paint. Do the 73's use the pad? I know many have gone through this. I would appreciate any help with which is the correct switch to use. Finally: HOW IN THE WORLD DO YOU GET THE NEW MOUNTING PLATE BACK THROUGH THAT LITTLE HOLE?

[Russ S.]

Re: 73 Rear Door Ajar/Alarm Switch Correct Replacement Question

Corvette Central part number 593140 which was used on 73s at least earlier cars. I don't no when they switched to the other style. Some 73s did have the pad. I think the factory only put them on if the door didn't contact the pin. My early 73 doesn't have them while my later 23000 mile one owner does.

[Jimmy P.]

Re: 73 Rear Door Ajar/Alarm Switch Correct Replacement Question

Russ,
I looked a that one from CC. It doesn't look like mine where the wires connect. I assume that red wire is a ground? I'll never be able to get that mounting plate up out of the rear well, to see how or where it was attached. Also I would think that little hole would need to be enlarged somehow to get the mounting plate in through it to replace?

[Alan S.]

Re: 73 Rear Door Ajar/Alarm Switch Correct Replacement Question

Hi Jimmy,
I believe that member Don Lowe faced a similar problem with the plate on his 72 convertible and came up with a workable solution.
Perhaps you might want to contact him by PM or e-mail if he doesn't see your post.
I'm sure he'll help you.
Regards,
Alan

[Jimmy P.]

Re: 73 Rear Door Ajar/Alarm Switch Correct Replacement Question

Hi Jimmy,
I believe that member Don Lowe faced a similar problem with the plate on his 72 convertible and came up with a workable solution.
Perhaps you might want to contact him by PM or e-mail if he doesn't see your post.
I'm sure he'll help you.
Regards,
Alan

Alan,
thanks, I may do that. I'll wait awhile to see if he or anyone else responds.

[Harmon C.]

Re: 73 Rear Door Ajar/Alarm Switch Correct Replacement Question

To install the metal plate I took a three foot rope and tied a knot in the middle. Feed the rope with the plate against the knot through the hole that must be enlarged then through the hole for the switch. You can pull on the rope to keep the plate tight while installing the pop rivets. The plate needs to be grounded on 73's after November 72 production. Early 73's had three wire switches. Later 73's had two wire switches and the third wire was attached to the metal plate and grounded on the inside behind the seat carpet.

[Jimmy P.]

Re: 73 Rear Door Ajar/Alarm Switch Correct Replacement Question

Lyle,
So, then the red wire must be soldered to the metal plate for ground on my car? Do both sides have the red wire? I can't remember seeing it on the right side.

[Harmon C.]

Re: 73 Rear Door Ajar/Alarm Switch Correct Replacement Question

Yes the wire must be attached to the plate.I tapped a hole in the plate and used a round eyed stake on. Both sides need the ground. I thought the ground wire was black,check behind the seat for the connection.

[Russ S.]

Re: 73 Rear Door Ajar/Alarm Switch Correct Replacement Question

I don't think red is every a ground wire. as Lyle says a grd wire s/b black.

[Jimmy P.]

Re: 73 Rear Door Ajar/Alarm Switch Correct Replacement Question

I'll double check the wiring tomorrow (later today). But I'm almost positive that the red wire was attached to the plate, I thought is was odd too. As I said the left side had two small screws holding it in place. The rivets were long gone. I'll post a thread later after I recheck.
thanks

[Russ S.]

Re: 73 Rear Door Ajar/Alarm Switch Correct Replacement Question

According to the wiring schematic in the service manual the wires s/b light blue,white, and black. Do you have the carpet out of the car? The wires run across the riser behind the seats and if the carpet is out you can check to see if someone has sliced in a piece of incorrect color wire.

[Jimmy P.]

Re: 73 Rear Door Ajar/Alarm Switch Correct Replacement Question

According to the wiring schematic in the service manual the wires s/b light blue,white, and black. Do you have the carpet out of the car? The wires run across the riser behind the seats and if the carpet is out you can check to see if someone has sliced in a piece of incorrect color wire.

Russ,
I went out checked the car this morning. My carpet is intact, so I really don't want to tear it up unless if have to. The three wires on the right side are correct colors light blue,white, and a blackish color. The three on the left are light blue, white, and not red as I previously mentioned but purple. (no I'm not color blind) LOL, so I presume then that someone has spliced a different wire on to the black? The purple one was definitely attached to the backing plate. So when I get all the parts together I will attach it to the plate.
I'm just starting to get in to all the wiring issues with the car, so it will be a long process I'm sure. My e-brake light doesn't come nor does my seat belt light.
But I must say that I am enjoying all this and learning as I go. Isn't that what the NCRS is all about.?
Thanks to all for the help.