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Old 11-01-2004, 02:48 PM   #1
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Default Backup Light - Neutral Interlock Question

My 93 SSE has a problem where the neutral interlock does not allow the car to be started in Neutral itself...you have to hold the shift between neutral and drive. Likewise, the backup lights do not function in reverse...you have to hold the shifter between reverse and neutral. My gut feel on this was a linkage adjustment issue, but I'm being told that the interlock switch controls both of these function and must be replaced @ $200+.

The car will only start in Park and you are required to keep your foot on the brake to shift out of Park. I would think if the switch itself was bad, these functions would be affected too.

Any suggestions?
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Old 11-01-2004, 03:32 PM   #2
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im not sure that you have a problem here............the car should not be allowed to start in any other gear than park, and you have to apply the brake to shift the car out of park. I had a problem with my shifter cable, it just needed adjusted
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Old 11-01-2004, 03:40 PM   #3
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The car should also start in Neutral. Something is definitely out of whack, but I don't know how to fix it til I get home to my FSMs
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Old 11-03-2004, 10:43 PM   #4
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Default Re: Backup Light - Neutral Interlock Question

Quote:
Originally Posted by BigGuy
My 93 SSE has a problem where the neutral interlock does not allow the car to be started in Neutral itself...you have to hold the shift between neutral and drive. Likewise, the backup lights do not function in reverse...you have to hold the shifter between reverse and neutral. My gut feel on this was a linkage adjustment issue, but I'm being told that the interlock switch controls both of these function and must be replaced @ $200+.
Well, yes, it does control both, but you don't need to replace it; you need to adjust its linkage so that it'* back in synch with the gearshift.

If I remember right, it'* not on the steering column as with older, RWD cars; it'* under the hood, on the transmission, a kind of rotary switch that rotates horizontally when activated by the shifter cable. Where the adjustment point is I don't know at the moment, but I'm guessing that it'* under the hood (and might have gotten knocked out of whack if anyone was doing heavy work like a transmission swap). Among other things, I believe that'* where the pale yellow starter crank wire from the ignition switch meets up with the purple solenoid wire that goes down to the starter.

Once you find the switch and its actuator cable, you may also see the adjustment for it, such as a clamp on the outer cable casing that can be loosened and reattached at a different spot.

Quote:
The car will only start in Park and you are required to keep your foot on the brake to shift out of Park. I would think if the switch itself was bad, these functions would be affected too.
No, that'* a completely different circuit inside the passenger compartment; it'* not related to this problem at all. The Park interlock requires you to apply the brake in order to shift out of Park, but the Neutral interlock, the switch we're talking about here, is what allows the engine to be started in either Park or Neutral, but no other gear positions.

Quote:
Any suggestions?
Hopefully this will give you something to hunt for under the hood, at least until one of us experts can figure out where we left our service manuals.
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Old 11-04-2004, 12:41 AM   #5
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Default Re: Backup Light - Neutral Interlock Question

Previously I wrote:

Quote:
If I remember right, it'* not on the steering column as with older, RWD cars; it'* under the hood, on the transmission, a kind of rotary switch that rotates horizontally when activated by the shifter cable.
Okay, I just eyeballed the thing on my own car, and doublechecked it in the manual. That'* it: The "Park/Neutral Position Switch"

It'* in plain sight under the hood. Look down from above at the left rear of the engine transaxle, directly below the master cylinder, and you'll see the shifter cable attached to the actuator arm, which in turn is connected to a vertical rod coming up out of the transaxle. The switch is the wide black plastic body under the actuator arm, sitting on top of the transaxle; there'* a fat wiring conduit coming in the outboard side of it.

From what I can see of it, the actuator arm shifts the transmission, and the vertical rod rotates the innards of the position switch at the same time.

There is some adjustment to the shifter cable where it emerges from its casing, but I think first you want to find out whether the cable is really out of adjustment, or the switch itself is out of position (if that'* possible). That is, can you select every gear with the shifter in each position, like normal, or is, say, Reverse itself out of position with the shift lever, the same way the lights are?

I'm going purely on what I've seen and read in the manual here; I've never had to do an R&R on this switch, so this is about as far as I can go here. I _would_ say that replacing the switch looks like pretty much of a no-brainer, since it'* held on with only two screws, plus the actuator arm to remove and the wiring harness to unplug, but I wouldn't buy a replacement until I was sure that the existing one was actually toast, and not just out of adjustment someplace, otherwise the new switch will end up just as out-of-position as the old one was.
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