C4 trans question

warpspeedmind

New Member
Nov 25, 2004
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Quick question - I've got an '88 HO engine I plan on dropping into my '79 Pace car. I bought it without a trans. and will be using a rebuilt C4. I have the wiring harness out of an '89 with an AOD. My problem is with the Neutral safety switch -

What should I do to the harness? Should I jump the wires or leave them unplugged? I won't be needing them, but I know something has to be sent back to the ECU. Any ideas?
 
Just off the top of my head, I would think you might need the ECM out of a 5 spd (A9L is it?). That doesn't require any info from the tranny. I take it you've worked out the vacuum source to the modulator and the downshift linkage already? Let us know.
 
I would think if you aren't worried about having the neautral safety feature then you would just jumper the two wires. I have never done this on a ford, but an older man I work with ripped his wiring harness on his old 70's dodge truck driving through a brush pile on the way to work. ( I have no idea why he was driving through brush on the way to work) Anyway at the end of the day the truck wouldn't do crap. While walking up to it I noticed the wires hanging underneath. I climed under there and hooking them together and closing the circuit is what worked on his till he could get a new harness.
 
so you are going from an auto car to an auto car (aod to c4)? if so, you might need to change the connector (if the C4 takes a different connector), but otherwise you should be fine, no? i would have thought C4's had the provision for a neutral switch.
:shrug:
 
You can just splice the wires to the C4 switch connector pigtail, or use 4 spade terminals. The C4 has a 4 wire switch, with a different connector than an aod, but I think the functions are the same, two wires for the start circuit, and two for the back up lights. I would hook it up, its fairly easy, and will prevent an incident later. I do not have the wire color codes handy, but they should be easy to find. Or just check continuity with the trans in park, reverse, etc.