Looking for neutral safety switch wire

[Wozny]

On a automatic is the neutral safety switch on the ground circuit or the positive starter circuit? Since I got my 92 back from the shop that swapped my auto for a 5 speed manual the starter won’t turn. I don’t have a schematic for it. Some trucks switch the ground at the tranny, and I have a few ( about 4) leftover wires from the automatic. (Speedo wires are on the T case). I read one thread on this forum that was about bypassing the neutral safety switch by connecting the purple wire from the solenoid to the yellow on the column. Thanks

 

[Nad_Yvalhosert]

There is no "neutral safety switch" on an automatic tranny.
On the 88-92ish with the 700r4, there is a shifter column position sensor.
On the '93-ish and up 4L60 there's a PRNDL switch on the transmission.

My '88 was swapped from a manual to an auto, there is a switch on the firewall behind the clutch pedal. You might need to get one from a boneyard and connect it to the shifter column position sensor.

 

[someotherguy]

There is no "neutral safety switch" on an automatic tranny.
On the 88-92ish with the 700r4, there is a shifter column position sensor.
On the '93-ish and up 4L60 there's a PRNDL switch on the transmission.

My '88 was swapped from a manual to an auto, there is a switch on the firewall behind the clutch pedal. You might need to get one from a boneyard and connect it to the shifter column position sensor.

Huh?

From 1994 all the way back to.. however long that column design was used in trucks, it goes back at least to squarebody era. There's a neutral safety switch near the base of the column. It locks out starter engagement unless you're in park, or neutral. I know you know this.. but maybe incorrect on the years you're mentioning. The GMT400's didn't get a transmission-mounted range switch until 1995.

Dead on about the clutch safety switch. It pretty much performs a similar function interrupting the starter circuit unless the clutch is depressed. One could simply jumper the wires from the automatic's neutral safety switch setup, or do it correctly by wiring in the clutch safety switch.

Richard

 

[GrimsterGMC]

My 1988 doesn't have an electric neutral safety switch as such, the shifter physical blocks the key from turning to start the engine when in gear. All it does have is a gear position switch at the base of the steering column that tells the ECU when the truck is in park/neutral but that has nothing to do with the starter.

 

[someotherguy]

My 1988 doesn't have an electric neutral safety switch as such, the shifter physical blocks the key from turning to start the engine when in gear. All it does have is a gear position switch at the base of the steering column that tells the ECU when the truck is in park/neutral but that has nothing to do with the starter.

Your column *should* allow you to turn the key to the start position with the shifter in neutral. If it doesn't, something is misaligned or worn, which wouldn't be surprising with trucks of this age.

Richard

 

[GrimsterGMC]

Your column *should* allow you to turn the key to the start position with the shifter in neutral. If it doesn't, something is misaligned or worn, which wouldn't be surprising with trucks of this age.

Richard

Yes it does in park/neutral but not in gear. But since I have a B&M Hammer shifter now I have wired a relay into the starter solenoid wire and control it with the park/neutral switch on the floor shifter that tells the ECU when i am in park/neutral.

 

[evilunclegrimace]

My 1988 doesn't have an electric neutral safety switch as such, the shifter physical blocks the key from turning to start the engine when in gear. All it does have is a gear position switch at the base of the steering column that tells the ECU when the truck is in park/neutral but that has nothing to do with the starter.

That is a neutral saftey switch and it does have some thing to do wit the stater. If you purposely mis align the switch the starter will not engage even if the trans is in park or neutral

 

[evilunclegrimace]

Neutral saftey switch.

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[L31MaxExpress]

Neutral saftey switch.

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That is for the reverse lights and for the Park/Neutral input to the early 92 down TBI ECMs which helps control the idle speed. The starter is done mechanically on the column, the shifter prevents the key from rotating to start position in gears other than Park/Neutral.

You can remove that switch entirely and the truck will still start.

 

[L31MaxExpress]

Your column *should* allow you to turn the key to the start position with the shifter in neutral. If it doesn't, something is misaligned or worn, which wouldn't be surprising with trucks of this age.

Richard

I assure you, the 94 and older automatic columns do not allow the key to be rotated to start outside of Park/Neutral. The start circuit is a purple wire straight off the ignition switch, without a starter interupt switch since it is done mechanically in the column. The key cylinder rack gear rotates/slides against a mechanical stop in Reverse or Drive positions preventing the key from rotating to the start position.

The 95+ have a yellow wire off the ignition switch, that runs to the transmission mounted interlock switch with a purple wire off that switch to the starter. 95+ the key can rotate to start in all shifter gear positions.