Let me preface this by saying that my 1975 Corvette a great resource. It was not been wrecked or otherwise modified with one exception. The smog system was removed when new (and is still completely inventories in boxes). However this does not effect any wiring harnesses.
I have recently circuit tested my 1975 wiring harnesses and compared them to the 1975 published GM wiring schematics. Comparing my 1975 I noticed the GM schematic is missing the pink wire in the dash harness for the factory alarm from the rear harness connecter to the fuse box. Whooooops, they all had alarms in 1975. The hood door control switch connector on the dash harness is missing one wire: three needed on 1975, not two as in 1973 and 1974. The passsengers side firewall connector of the dash harness omits an orange jumper wire to the other firewall connector. The yellow lead on the radio connecter does not directly connect with the fuse box. The schematic for an auto trans solenoid accessory harness shows those wires connecting to a (1974 and earlier style) 14 wire cavity connector, instead of the actual 20 wire cavity connector used in 1975. They are vasty different and you cannot connect a 14 & 20 connecter together. And the wires aren’t even in similar spots. A carb idle solenoid connection is shown, but none have been discovered in my garage, the World or Oz to date. The fuse box illustration omits the power accessory terminal identifications as well as the fuse rating. There are actually two different dash wiring harnesses on 1975: one automatic and the other 4 speed. The GM schematic only shows the latter 4 speed, and thus the 75 percent of 1975 owners with automatic can only guess about those 2 automatic neutral safety switch connectors on the dash harness.
There’s more, but I think you may get the idea. May all your sparks be right on and not crossed. There is nothing worse than a dim bulb, unless you are a Luddite.
Geoffrey Coenen
PS If you know more, I’d be pleased to examine and include your findings. If however you are located in the State of Denial, or a Disciple of Daun, please accept my apologies for interrupting your nap or alumibeer festival.
If I understand the CF rules and regulations correctly, and I’m not sure my edition of Roberts has the complete Net appendix - it is considered bad form if I answer a direct question that would materially effect my commercial bank account in a positive manner. Therefore should anyone query a commercial question as opposed to a technical one, it is apparently not appropriate to answer within this privately held public platform: CF. It’s actually a well know business principle of which I am personally quite familiar: He who signs the checks makes the rules.
If you wish to contact me regarding a personal matter, I answer email but accept no attachments. If you wish to include a photo, please post it on the net and provide the url.
I turned on the alarm located on the driver front panel. When I returned to my car I could not get the key to turn in the opposite direction in my attempt to turn off the alarm. Is there something else involved in turning off the alarm other than turning the key?
If not and I can not get the key to turn; how would I disarm the alarm. The alarm seems a bit useless anyway, if you can start the ignition the alarm stops sounding.
Thanks in advance for your help.
Corvette Store
Tip using the 1975 GM wiring schematics
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