I have an 86 without cruise. I've been reading up on it, and got all the parts from the junkyard. I have the harness for the passengers compartment, all of the switches for the pedals, but when I went to try and get the wiring harness from the engine compartment I couldn't figure it out. It seems to go from the servo out of the engine compartment on the left side..and underneath the plastic body panels. The pages I found on the cruise system in the manual is no help.
I don't get how to wire the servo up. I figured it was worth a try to put in the oem system, since I've got two of everything from the junkyard. I just can't figure out the wiring in the back. Obviously something is missing, maybe when the engine was rebuilt by the previous owner the cruise wiring was left off. Any ideas how I can know how to wire this thing?
What I would do is take the information from the factory service manual (Helms) and make my own harness. It's usually a lot more work and unnecessary to use the factory harnesses. I don't have a book for the 86, but I'm sure someone can post the information for the 86 and you can just wire it up.
Because engine harness does not have cruise wiring.
That's bundled in taillight harness. Need full harness then pull off rear body.
This is true. I got the cruise wiring for free when I did my fastback conversion on my coupe. But installing a new tailight harness is a ridiculous amount of work just to get cruise. Now if you want a 100% OEM look I suppose it's worth it, but I would never do that.
After looking at the wiring diagram, I am considering splicing into the C500. This is where the harness comes back into the engine compartment. I realize that it is not as good as digital cruise, but I have all the parts, and the stalk ((installed), so I thought it might be worth a try. There are 5 wires that I have to take from the Servo to C 500. Any thoughts, besides "you're crazy"?
I have a follow up question on cruise control I wonder if I could get help with. I just re-installed the cradle on my 88GT after a top-end rebuild and clutch change. I'm now hooking everything back up, but am not clear on a couple of things, one is the vaccum line setup for the cruise control. I should have taken more pictures, I realize, but since some hoses were completely rotted out and missing, even that wouldn't have solved all problems. Does anyone have a diagram or a photo of a proper setup? Biggest question: what's the vacuum source? I have no hose leading into the main control valve. Thanks, guys!