I wanted to put a keyless entry into my 1979 Corvette because of constant problems with trying to unlock the doors. I always felt that I was going to snap the key off in the tumbler. Know the feeling? Anyway….. I finally figured out the correct way to install one.
First the semi-technical dope…. The 1979 Corvette (maybe your C3 does as well) uses a “reverse polarity” locking system. (Sometimes called a 5-wire system as well) Constant power is delivered to both door locks…always….. and when you hit the door lock a pulse goes through the system and then grounds out on the passenger side flipping the switches along the way so it’s ready for the next pulse….hit the switch again and a pulse goes the opposite way through the system and reverses the circuit….thus the “reverse polarity” name.
This causes some head scratching because most new cars today don’t use the reverse polarity system anymore and thus, most new keyless entry systems aren’t set up for this. (I felt like I was trying to install Play Station 3 technology into SkyLab!!!!!) It was a damn frustrating mess. I did not want my fellow Vette’rs go through the same pain so here is how to do it.
You need to add a few relay switches to the system. I’m not sure why, but you have to insert the relays into the driver side. (passenger side install does not work…I tried it!) See the diagram below. Basically your inserting two relays (about $10 each) between the door lock switch and the door lock actuator along with your keyless module. I checked four auto stores and none of them had them….you have to go to a store like Best Buy or a car stereo install place to get the relays. I installed an Audiovox AA-925 Keyless Entry system….$49. It has a lot of extras that I will get to later.
There are five wires to each relay that need to be hooked up.
Cut the gray and tan wire coming from the switch and hook it up to the relays shown on the diagram and as described below. Use a meter to find the “power send” wires from the switch.
Here is the layout to the relay switches. They are numbered as follows:
(87a) gets the tan and gray wire from the door lock switch. One relay gets the gray wire and one relay get the tan wire.
(30) gets the tan and gray wire from the door actuator side. See my diagram.
(86 and 87) Wire all these together and connect it to the “power in” wire at the door lock switch. This means you have to cut the orange wire going into the door lock switch. (I hope you disconnected your battery!!)
(85 and 85) Last are the lock pulse and unlock pulse wires from your keyless module. Your lock pulse wire goes to the same relay that you connected the gray wire to 87a. Your unlock pulse wire goes to the other relay 87a…again see the diagram.
(Ground) Make sure you don’t forget to hook this up. Just ground it to a bolt on the door frame somewhere.
(Power) You have to hook up your keyless module power to the orange wire going into the door lock switch as well.
There are a ton of wires all jumbled up together with this install so go slow and take your time because things get confusing in a hurry!
Hope that helps….. this was an extreme pain in the ass for me to figure out because the manufacture’s diagram they sent me for the Audiovox was wrong for a reverse polarity system!!!!!! They had the 85 and 86 as being the lock pulse wires. IF YOU SEE THIS IN YOUR KITS DIAGRAM IT’S WRONG!!!! It should have been 85 and 85 being the lock and unlock pulse wires. Needless to say I sent the manufacture a bitch slap e-mail over that little problem.
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