2003 cadillac deville-car will not start as if neutral safety switch is bad, but is not. Starter good, could security have locked down at times

Question edited for clarity.
Question moved to model category.

It is in the engine compartment Fuse and Relay Center. However, it may not be that but good place to start.

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Test, don't just blindly replace components.

https://www.google.com/search?q=1996+Cadillac+Deville+no+crank+no+start

Best idea by far. A pro grade scan tool computer can diagnose in 20 minutes

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Might be the neutral safety switch. Is the security ligt blinking?
Do It Yourself Diagnosis and Repair

It could be the neutral safety switch which prevents you from cranking the engine in gear.
But it could also be the anti-theft system. The system reads the chip in the key to allow the starter to crank the engine.
Is the security light staying on ?

This switch opens the starter circuit when the transmission is in any gear but Neutral or Park on automatic transmissions.


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No, not that switch, but the brake light switch on the brake pedal. It may just need adjusting to turn off when brake pedal is not pressed.
The neutral safety switch is in your starting circuit to keep car from starting when not in park or neutral.

Electrical problems require tracing from where you have current to where you do not. For example, it could be dirty battery terminals, back chassis ground connection, missing engine ground strap, bad neutral safety switch, bad ignition switch, bad starter solenoid, bad starter field or armature brushes.
See if there is current at the starter solenoid, when you try to crank it, with a test light. They move further upstream if there is not.

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Check the battery wire to starter with a volt meter is there 12 volts? if so check neutral safety switch. Place trans in neutral will engine start now?

Thank you for using FixYa.com

Regards, Lee Davidian

So you have no crank no start correct. Three possible items to check : ignition switch,neutral safety switch, starter relay. and if applicable starter interrupt relay.

Compare you current key and your spare key to see is there a missing VAT chip.



With the brake on move shifter to N and try to start the engine.
You may have to move it between P and N few times to check the contacts of the neutral safety switch.

The neutral safety switch will going back.

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.