A couple of Auto to 5-speed Wiring Harness questions

ForcedTorque

ForcedTorque

Join the 92 Owners Group
Jul 11, 2005
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Satsuma, Alabama, United States
I have finally gotten a hold of a good wiring harness for my 92 5-Speed, but it is an Automatic harness. I have always heard that it was a simple thing to make it work. I have already pulled the makeshift converted harness from my car, and I have a little confusion.

First, I'm confused with the wiring at the transmission. On the 5-speed harness, there was a long wire coming from the harness and connecting on top of the R-154. What is that wire for? The automatic harness does not have a wire that will reach that far. Also, my R-154 currently has what looks like a speed sensor with a long wire just tied off. That could reach to this auto harness, if it has a fitting plug. My best guess, is maybe at one point I need a plug, and all I could come up with was an auto speed sensor? Can anybody make any sense of all of this, and give me some guidance?

And, is there a write up on how to make the neutral safety switch and reverse lights work. I know, I should search, and I will, but a quick link would be appreciated if anyone has it handy.
 
D

Dan_Gyoba

Turbo Swapper
Aug 9, 2007
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long wire to the top of the transmission would be for the reverse lights. (Well, top RIGHT is reverse lights. Top LEFT is for ABS speed sensor, if equipped with ABS.) For an automatic, the reverse lights connect elsewhere, I believe at the shifter, but I'm not 100% on that.

Long wire tied off might BE a speed sensor for ABS. This would be a 3 wire harness then. The reverse lights is 2. If there's a fitting plug, plug it in. I believe that the ABS transmission sensor is at least compatible from R154 to A340E (And W58, for that matter. The R154 speed sensor didn't give the ABS computer from my '89 NA any trouble at all.)

Look at the TEWD for the neutral safety. There's some differences in how the auto and manual chassis are wired, but this is what I'd do:

The current neutral safety has a black-white and black/light blue wire connected to it. If it has contiunuity between them, the car can start, otherwise no.

Option #1 (Easy): Connect the wires. This disables the neutral safety, and does not instate the clutch safety. Lots of people with heavy clutches do this to avoid walking the crank.

Option #2: Take the wires on the clutch pedal assembly that you have for the clutch switch. Either use a relay (one wire to ground, other wire to pin #85 on relay. Pin #86 to ignition switched, fused power. Pin 30 to black-white wire, pin 87 to black-light blue wire.) Duplication of clutch switch achieved. If the factory neutral start is a relay, just re-wire the signal to the wires on the clutch switch.

Option #3: Re wire the starter circuit to bypass the black-white wire and include the clutch start switch, so that the wiring resembles the factory option for a manual transmission. (This would be my own preference, for ease of future wiring projects, like remote start.)

Important: There are 2 switches on the clutch pedal. One is normally closed, and opens when you just start to press in the pedal. That one is for the cruise control to shut it off when you press in the clutch. The other is normally open, and closes when you press the pedal almost to the floor. This is the clutch start safety switch, and is what you should use.
 
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