(help!!) Information On 1972 Vette Anti Theft Alarm System

[Terry M.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

If the diaphragm is rusted through, unless you can find another diaphragm it is toast. You may not be able to tell the condition of the internal pieces until you get it apart.

The rivets have to be ground down on one side and then pushed out with a punch. They can be replaced with small screws, but the screws have to be really tight (and stay that way) for the horn to work and sound the right tone. Once the screws are in tight, and you know the horn is working, the slot in the head of the screw can be filled in with caulk and everything painted.

Of course there is always the chance the electrical circuit in the horn is damaged, and then one would need donor pieces from another horn.

There are folks who fix horns who advertise in The Driveline. Ask them if they do alarm horns. The learning curve may be too steep, and parts amiability too difficult for the armature.

[Paul O.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

Vincent

Check with Joe Perri in Chicago, IL phone number 312-307-1977 he rebuilds Horns and Radiator caps does excellent work.

Paul 18046

[Vincent F.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

Thankyou all, I'm going to open up this horn, love a challange.

[Don L.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

Ron Goralski (fellow NCRS member) did mine a couple years ago. Great work, great guy too! He comes recommended by me. He's located in MD. PM me if you want his contact info.

[Jim T.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

Terry M. ref your post "Jim,
Are you sure the door ajar switch (at the back of the door jamb) connects to the alarm? On my 1970 the alarm switch is the same switch that lights the courtesy lights -- at the front of the door jamb."

I "assumed" that the door ajar activation switch was the location for the alarm activation wire for the door positions.
Thanks for noting/confirming the correct location.

I have the 1970 and 1971 service manuals and they do not have the wiring diagram for the factory alarm. I did make a copy from a later service manual, either 72 or 73 that is stored somewhere, I should have located it and reviewed the wiring diagram.

My 70 does not have the factory alarm system. When I bought it new off the showroom floor in TX I wanted the factory alarm since my 64 Corvette had been recently stolen. The dealer sales manager said they would install it to make the sell. Long story about this, short version is that I still have the factory GM alarm system wiring in the original part container still coiled up.

[Don L.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

1972 has 2 separate door jamb switches on each side. Front is for the courtesy lights and rear activates door ajar and alarm systems. I think the switches are different part numbers as well. Both did, however, have the "SX" tatoo on them, or at least should have them to be correct.

[Terry M.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

In one of my earlier posts I mentioned the change in location of the alarm switches. I knew for 1970 they were off the front of the door jam, and in 1972 they are off the back. I wasn't sure about 1971, but now baring an early or late story, we can narrow that down. I kind of thought that when the alarm system became standard the alarm switches became part of the door ajar switch on the back of the door jam. My guess is -- less wire = less cost.

I don't have a 1973 FSM, but do have a 1972 FSM -- so it must be in the 1972 OR it was in Chevrolet Service News. The latter is not commonly available to us.

The letter that accompanies the diagram in Vette Vues states that they are not making the diagram public through their usual technical channels for security reasons. Kind of a joke now days given how primitive the system is -- but then we have come a long way baby. I almost don't have a key for the 2008 Corvette -- and what passes for a key for that car, I hope I never have to use.

[Dennis B.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

Bill,

Here is a link for a horn rebuild kit at Zip Products if you are inclined to try it yourself. There also is a link on that page for detailed instructions on doing it.

http://www.zip-corvette.com/Zip/productr.asp?pf%5Fid=M%2D3065&gift=False&HSLB=False&mscssid=7AEA0D7C8B204A35AA5D6C875EDE7EEC

I just got my '72 horn working. There was a post somehwere on the NCRS site suggesting taking the adjustment screw out and spraying WD40 into it. Did that and cleaned all the contacts and the horn now works. Maybe I just got lucky.

Denny

[Terry M.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

That kit and instructions sure are handy. Good catch. The only reservation I would have is that it is not clear that kit will work for an alarm horn. I am not saying it won't -- I just don't know. Perhaps someone reading here has experience with it on an alarm horn.

[Dennis B.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

The part description on the vendor site says "fits 64-72 front horns & 68-75 rear alarm horn" but it would be good to know if anyone has successfuly done it with this kit.

[Terry M.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

Sorry Dennis, I missed that note about the alarm horn. Looks like that might be just the ticket for someone wanting to DIY. If my memory is right ZIP offers an NCRS discount too.

[Vincent F.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

great info on the horn rebuild kit. question,if you hook the horn direct to a battery it should work even without a relay?
Also my early 71 alarm uses the door jam switches at the hinge side of the jam.

[Terry M.]

Re: (help!!) Information On 1972 Vette Anti Theft Alarm System

Yes Vince, if you hook the horn direct to the battery no relay is needed -- but you do need good firm connections with a good size wire. #12 would be a good size.

Thanks for the info on your early 1971 pin switches. I would be real curious if the alarm switches moved to the rear in late 1971 -- like the 1972s are.