NHTSA VEHICLE ADVISORY
for Law Enforcement Agencies  April 1, 1999

From: National Highway Traffic Safety Administration (NHTSA)
Spec: Ford Police Vehicle Users

A number of police fleets have had their Ford vehicles--Crown Victorias, Econolines, etc. -- modified to flash the brake lights whenever the police lights are turned on. In some cases this modification may disable the brake shift-lock in Ford models-the Chevrolet Caprice does not appear to be affected. The shift-lock prevents shifting the vehicle's automatic transmission out of "Park" unless the brake pedal is simultaneously pressed. On December 4, 1998, two persons were killed and nine injured when a 1997 Ford Econoline van suddenly accelerated into a crowd of people. The crash occurred when the driver inadvertently pressed the accelerator instead of the brake pedal and shifted from "Park" to "Drive." The van was equipped with police lights and had been modified so the shift-lock did not operate at that time.

If your vehicles' brake lights do not flash when the police lights are on and the brake light circuit has not been modified, your shift-lock operation should not be affected.

To assure that your vehicles shift locks are not affected, perform the following tests:

First confirm the shift-lock is operating properly with the police lights OFF by performing the following procedure: 

1. With the engine running, parking brake firmly set, transmission in "Park," and the police lights off; attempt to shift out of "Park" without pressing the brake pedal. You should not be able to shift the transmission. If the transmission can be shifted, have the vehicle inspected for a faulty shift-lock system.

 If the previous test confirms the shift-lock is operating properly with the police lights off, then test the shift-lock's performance with the police lights ON as follows:

1. With the engine running, parking brake firmly set, transmission in "Park," and the police lights on; attempt to shift out of "Park" without pressing the brake pedal. Try this test a number of times to ensure accurate results.

2. Repeat this test in each of the possible police lighting modes on that vehicle.

3.  Be careful when conducting these tests--the vehicle may move suddenly.

 If the transmission cannot be shifted out of "Park" without pressing the brake pedal, your vehicle is equipped with a functioning shift-lock device. However, if the transmission can be shifted out of "Park" without pressing the brake pedal when the police lights are on, your vehicle has been modified so that it does not operate as intended by Ford, and could present a safety risk.

Crown Victoria police vehicle owner's manuals include the following warning from Ford:

"Aftermarket Equipment Installation"

DO NOT make electrical connections to vehicle electrical systems not specifically designed for aftermarket equipment installations.

Do not install any components into the Power train Control Module (PCM) or PCM harness. Connecting into this system may affect engine and transmission operation.

As an example: connection of aftermarket electrical equipment into the brake light circuit or any other circuit which is connected to the PCM, anti-lock brake computer, airbag system, or any other vehicle system will cause vehicle malfunction." [Emphasis added.]

Additionally, some fleets may find that the Center High-Mounted Stop Lamp (CHMSL) flashes with the brake lights when the police lights are activated. This modification does not conform with Federal Motor Vehicle Safety Standard (FMVSS) 108, which requires that the CHMSL only illuminate when applying the brakes, and not flash.

Should you find that the shift-lock is not operating properly and/or that the CHMSL flashes when the police lights are on--we recommend you restore intended performance by removing the electrical wiring modifications discussed above.