I have a 1992 Aerostar 3.0. My wiring diagram says it is good for 1992-1995 so this should help if you if you have the 3.0. The tach wire is the tan colored wire that connects to the coil on top of it. In order to get to it, take off the engine cover on the inside of the car and the coil is right there on the left. But in order to install a tach, you need to find a lead 12 volt + , and a ground and maybe a 12 volt for the light. I have not found where to tap into to get mine hooked up yet but I did hook mine right up to the battery to test it and it does work. Good luck On the passenger side wheel well there is the ignition control module, one of the pins, I think #5 of the 6, is an electrical output for a tach. I used it in a 94 Aerostar to put a tach on the dash. It is shown in the Engine Electrical section of the Chilton Manual.
Try this website http://www.installdr.com/QuickWiring.html
picture of engine of 1991 ford aerostar van
where can i find a vaccum line diagram for a 1992 ford aerostar with a 3.0 engine
I went to the ford dealership, to the parts department and asked if one of the mechanics could give me a print-out of the radio diagram. They gave this to me free of charge.
I went to the library and they have books on all years and makes of ford vans . I found the diagram for a 78 ford vans fuse box and then photo copied it.
How about torques for 1995 Aerostar XLT 4.0L front "spindle" nuts for the disk brake HUB (under the castle -nut). New hub/disk, new bearings - packed with amsoil synthetic grease, and new calipers/pads. Cheers!
The fuse diagram for my 1994 Ford Aerostar is located on pages 339 to 345 of the Owners Guide that came with the vehicle when we purchased it new.
You need to go to a car parts store, and get a repair manual for your car. They cost about $16.00 Or, go to a Public Library.
Autozone worked very well for me on my 91' Aerostar 3.0 .
go to napa auto parts online
In the common workshop manual by Haynes.
just so you know when i put a new stereo in my aerostar i had to run new wires to the stereo speakers because the stock stereo had a common ground so one ground for two speakers i damn near fried the deck figuring that out hopefuly you wont.