Where is the gauge hole on the neutral safety switch

The neutral safety switch is located on the transmission shift lever. Its held onto the transmission case by 2 bolts in slotted holes. You will need to remove the kickdown lever. The switch will slip off the shift lever with just a little pry if dirty. Replace the switch while the transmission is in neutral. There is a small hole in the side of the switch to stick a small pin or awl into to locate the neutral position of the switch. I would try to adjust the old switch before replacing it.

look for security light when you turn on key if it lights and doesn't go off leave key on for ten minutes then turn key off and then try to start

Test/Service/Replace Neutral Safety Switch
Most neutral safety switches are combinations of a neutral safety switch and a backup lamp switch. Others have separate units for these two distinct functions. When the reverse light switch is not part of the neutral safety switch, it seldom needs adjustment, as it is directly activated by the transmission or the gear selector linkage.
Typical location of a neutral safety switch on a transaxle. Reprinted with permission of Ford Motor Company. A neutral safety switch allows current to pass from the starter switch to the starter when the lever is placed in the P or N position. Some neutral safety switches are nonadjustable. If these prevent starting in the P or N position and the gear selector linkage is correctly adjusted, they should be replaced.
To adjust a typical neutral safety switch:

• Place the shift lever in neutral.
• Loosen the attaching bolts for the switch.
• Using the angling pin, move the switch until the pin falls into the hole in its rotor.
• Tighten the attaching bolts.
• Recheck the switch for continuity. If no voltage is present, replace the switch.
• The switch sometimes controls the operation of the back-up lights also. With the engine off and the key on, put the selector in reverse position. Check the back-up lights to see that they are on. Then, check in the drive position to see that they are out.

Safety Switch Most neutral safety switches are combinations of a neutral safety switch and a backup lamp switch. Others have separate units for these two distinct functions. When the reverse light switch is not part of the neutral safety switch, it seldom needs adjustment, as it is directly activated by the transmission or the gear selector linkage.
Typical location of a neutral safety switch on a transaxle. Reprinted with permission of Ford Motor Company. A neutral safety switch allows current to pass from the starter switch to the starter when the lever is placed in the P or N position. Some neutral safety switches are nonadjustable. If these prevent starting in the P or N position and the gear selector linkage is correctly adjusted, they should be replaced.
To adjust a typical neutral safety switch:

• Place the shift lever in neutral.
• Loosen the attaching bolts for the switch.
• Using the angling pin, move the switch until the pin falls into the hole in its rotor.
• Tighten the attaching bolts.
• Recheck the switch for continuity. If no voltage is present, replace the switch.
• The switch sometimes controls the operation of the back-up lights also. With the engine off and the key on, put the selector in reverse position. Check the back-up lights to see that they are on. Then, check in the drive position to see that they are out.

Nope. The neutral switch has 2 functions. It prevents the engine from starting in any other gear but park and neutral. It also switches on the back up lights when in reverse. You have electrical problems located elsewhere.

You probably need a linkage adjustment,a neutral safety switch adjustment or replacement of the neutral safety switch.

Check the next diagrams...



Fig. 1: Neutral/Park position switch-3T40 transaxle



Fig. 2: Neutral/Park position switch-4T60-E transaxle


ADJUSTMENT

1. Place the shifter in the N detent.
2. The switch is located on the shift shaft on the top of the automatic transaxle. Loosen the switch attaching bolts.
3. Rotate the switch on the shifter assembly to align the service adjustment hole with the carrier tang hole.
4. Insert a 3 /32 in. (2.34mm) maximum diameter gauge pin into the hole to a depth of 9 /64 in. (9mm)
5. Tighten the mounting bolts and remove the pin.

Hope this helps (remember rated this).

Ford Neutral Safety Switch; Ford Reverse Light Switch; Backup Light Switch.

The Neutral Safety Switch wires in my 1971 Ford F100 are orange with a blue stripe.
The Reverse, or Backup Light Switch wires are black with a red stripe.

There are two sets of two wires across this combined neutral safety and backup light switch, for a total of 4 wires. Photos are at the end of this post.

The switch for the 1971 Ford F100 pickup truck is the same as in many other years and models. For details, including parts numbers, see the following quote from an expert at Ford Truck Enthusiasts:
http://www.ford-trucks.com/forums/287185-back-up-light-and-neutral-safety-switch-2.html#post5601846

The neutral switch also controls the backup lights, and is the same 1967/77.

C7TZ-7A247-A .. Neutral/Backup Switch (Motorcraft SW-600)

There is no separate backup light switch..except on 1967/68 F350's.

Neutral switch location 1967/77:

The plastic half moon shaped neutral safety switch mounts on the outside lower portion of the steering column (NOT on the transmission!).

It's activated by an inverted Y shaped lever that snaps on the shift tube

D0TZ-7B097-B .. Lever, Neutral Switch Actuator = From FTE sponsor DIRECT FORD PARTS: Ford suggested retail price: $18.72 / FTE member net: $13.23.

The switch is also still available from Ford, but the website is down so I can't post the list & net prices. .

1978 is the FIRST year the F100/350's have the neutral switch mounted on the transmission. __________________

Bill // Retired Ford Parts Manager // SoCal Chapter member // Part Number Research: 1928/2001 FoMoCo vehicles.

IMAGES

Driver side of the neutral / reverse switch showing the travel slot for the switch arm, the return tensioning spring, and the arm.


The front, steering wheel side of the neutral / reverse switch after removal from the steering column. The switch's two functions are actuated when the lever in the column moves the switch lever shown here to different positions as gears are selected.


The neutral switch is installed on the steering column near the firewall, with 5/8" bolts into the steering column (visible hole) and down column from a rectangular opening in the column housing. The actuating lever for the switch is attached to the gear shift shaft inside the housing; the lever is visibly protruding from the opening in this image.


Back of neutral / reverse switch, showing the wiring attachments. Black with red stripe is the backup light wiring, Orange with blue stripe is the neutral safety switch, it prevents starting in gears other than neutral & park.

Use like reference guide for GM Cadillac 1967-1989 Repair Guide Neutral Safety Switch - REMOVAL & INSTALLATION

All Except 1985-89 Eldorado and Seville
See Figure 1
The neutral safety switch prevents the engine from being started in any transmission position except Neutral or Park. The switch is located on the upper side of the steering column under the instrument panel on column shift cars, and inside the shift console on floor shift models.

1. Remove the console for access on floor shift models.
2. Disconnect the electrical connectors.
3. Remove the neutral switch.

To install:

1. Place 1967-70 column shift lever models in Drive, and 1971 and later models in neutral. Locate the lever tang against the transmission selector plate on column shift models.
2. Align the slot in the contact support with the hole in the switch. Insert a 3 / 32 in. (2.38mm) diameter pin in place. The switch is now aligned in Drive position.

1973 and later neutral safety switches have a shear-pin installed to aid in proper switch alignment so that insertion of a pin is unnecessary. Moving the shift lever from Neutral shears the pin.

1. Place the contact support drive slot over the drive tang. Install the switch mounting screws.
2. Remove the aligning pin. Connect the electrical wiring, and replace the console.
3. Set the parking brake and hold your foot on the service brake pedal. Check to see that the engine will start only in Park or Neutral.

Fig. 1: Installation of a common neutral safety switch



ADJUSTMENT
See Figure 2
1974 and later cars do not have a neutral safety switch. Instead, these cars have an interlock between the lock and the transmission selector, which is non-adjustable.

1. Place the shift lever in Neutral.
2. Move the switch until you can insert a gauge pin, 3 / 32 in. (2.38mm) diameter, into the hole in the switch and through to the alignment hole.
3. Loosen the switch securing screws. Remove the console first, if necessary.
4. Tighten the screws and remove the pin.
5. Step on the brake pedal and check to see that the engine will only start in Neutral or Park.
   

Fig. 2: Adjustment of a common neutral safety switch


1985-89 Eldorado and Seville
See Figure 3

All neutral safety/back-up light switches come with a small plastic alignment pin installed. Leave this pin in place.

1. Place the shifter assembly in the Neutral position.
2. Remove the shifter lever-to-switch nut and the lever.
3. Disconnect the electrical connector from the neutral safety/back-up light switch.
4. Remove the neutral safety/back-up light switch-to-transaxle bolts and the switch from the vehicle.

To install:

1. Position the shifter shaft in the Neutral position.

If using an old switch or the plastic pin (new switch) is broken, install a3/32in. (2.38mm) diameter pin gauge (drill bit) into the neutral safety/back-up light switch; the switch is then locked into its Neutral position.

1. Align the flats of the shifter shaft and the neutral safety/back-up light, then, align the switch-to-tang on the transaxle. Torque the switch-to-transaxle bolts to 22 ft. lbs. (30 Nm). Remove the pin gauge.
2. To complete installation, reverse the removal procedures. Make sure that the engine starts only in the Park and Neutral positions.
   

Fig. 3: Neutral start and back-up lamp switch - 1985-89 Eldorado and Seville

Hope help with this (remember rated and comment this). Good luck.

Neutral Safety/Back-up Light Switch

This is a combination switch which controls both Neutral Safety and Back-up lamp circuits.

C6 Transmission



C6 neutral start switch

1. Disconnect the negative battery cable.
2. Raise and safely support the vehicle on jackstands.
3. Remove the downshift linkage rod return spring at the low-reverse servo cover.
4. Coat the outer lever attaching nut with penetrating oil. Remove the nut and lever.
5. Remove the 2 switch attaching bolts, disconnect the wiring at the connectors and remove the switch.
6. Installation is the reverse of removal. Adjust the switch and tighten the bolts to 55-75 inch lbs. (6.2-8.5 Nm).
7. Remove the jackstands and lower the vehicle.
8. Connect the negative battery cable.

AOD Transmission



Removing the AOD neutral start switch

1. Disconnect the negative battery cable.
2. Raise and safely support the vehicle on jackstands.
3. Disconnect the wiring from the switch.
4. Using a deep socket, unscrew the switch.
5. Installation is the reverse of removal. Tighten the switch to 10 ft. lbs. (14 Nm).
6. Remove the jackstands and lower the vehicle.
7. Connect the negative battery cable.

4R70W Transmission




Removing the Manual Lever Position (MLP) sensor

As of 1994, the neutral safety switch is referred to as a Manual Lever Position Sensor (MLP).

1. Disconnect the negative battery cable.
2. Raise and safely support the vehicle on jackstands.
3. Disengage the harness connector from the MLP sensor.
4. Remove the 2 sensor attaching bolts and remove the sensor.

To install:

1. Install the MLP sensor and install retaining bolts. Do not tighten, the sensor requires adjustment.
2. Adjust the MLP sensor then tighten attaching screws to 80-100 inch lbs. (9-11 Nm).
3. Remove the jackstands and lower the vehicle.
4. Connect the negative battery cable.

ADJUSTMENT

C6 Transmission

1. Hold the steering column transmission selector lever against the Neutral stop.
2. Move the sliding block assembly on the neutral switch to the Neutral position and insert a 0.091 in. (2.3mm) gauge pin in the alignment hole on the terminal side of the switch.
3. Move the switch assembly housing so that the sliding block contacts the actuating pin lever. Secure the switch to the outer tube of the steering column and remove the gauge pin.
4. Check the operation of the switch. The engine should only start in Neutral and Park .

4R70W Transmission




Adjusting the MLP sensor

Park is the last detent when the manual control lever is full forward. Return 2 detents toward the output shaft for Neutral.

1. Position the manual control lever in Neutral .
2. Insert Gear Position Sensor Adjuster tool T93P-700 10-A or equivalent, into the slots.
3. Align all 3 slots on the MLP sensor with 3 tabs on the tool.
4. Tighten the attaching screws to 80-100 inch lbs. (9-11 Nm).

I hope help you. Good luck (rated this help).