There's an easy way to do it.
Take a spare garage door remote, then find how the switch/button works. Most of them it just makes a contact between two points on the circuit board. Solder a wire from each contact, long enough to reach near the hazard switch.
Then...if you don't have a convertible, grab a hazard/convertible top switch assembly. The wire for the top is already in the harness (or is on both of mine), you can remove (cut) the plug from the harness since you're not going to use it anyway. Or pick one up from a JY or ebay or whatever which is how I did mine. You will need a relay. If using an 87 relay (87a can be used but it not necessary), pin 30 goes to one of the wires from the remote, 87 to the other. They just make contact between them when the relay is energized. 85 can go to either +12v (batt) or +12v (ign), depending on if you want it to work with the key off or not. 86 goes to one of the wires on the convertible top switch depending on if you want to be able to "push" to open the garage or "pull" to open.
-to "push", pin 86 of the relay will go to pink on the switch harness. To "pull", use GY/LB. That puts +12v switched to the relay, which energizes the relay, the relay makes contact between 30 & 87 and it triggers your remote.
Mine's a little different in that it's a 2.3 turbo out of a Turbocoupe, using a TC computer which has octane adjust. In factory application, you could switch it to "premium" mode or "regular" mode, the difference being that in "premium" the timing curve was a little more aggressive on the top end, among a few other things. On my '93, I have the oct adj wired to the convertible top switch, but since the switch is momentary, I had to make a detent, so push it in for "premium" and pull it back to "neutral" (switch in middle) for "regular", then "pull" the switch to the rear to open the garage. Girlfriend laughs about it, push the switch in for "TOP" power. Whatever. The difference isn't that noticeable; this time of year with cool heavy air, what I notice is that when boost comes on, it hits harder and faster than in "regular", destroys tires in the first 3 gears when it hits. I about lost it this morning in a hurry on the way to work, went to pass another car on the highway in 3rd at about 50 when it hit and got sideways. Guy in the truck I passed gave me "the bird" big time.
I hope I got the pin #'s right on the relay....just going off of my memory. It's real simple.
I just put a litlte hole in the case of the remote with the wires run through the hole; my remote has a two-piece case and the case splits in the center, notched the case halves, ran the wire through, stuck some velcro to the case and velcro'd it to the back side of the dash, out of sight & out of mind. What is kinda funny about it was that after I got it done, the GF was out in the shop and I showed her what I done, and she said "you're a genious". No, I'm not....it was actually a crappy idea. I was sitting on the toilet thinking what can I use the "pull back" function of the convertible top switch for since it's momentary and it hit me, why can't I use it for the garage door?
