I am having problems starting my car in the park position. When it doesn't start in the park position, I have turned the car switch on and moved the gear to neutral to start it. Now it seems to be getting worst. I have tried to troubleshoot the problem in Mercedes-Benz E-class Owner's Bible, but have not been able to find it. I think it is called a neutral safety switch. I would also need the location of it and installation instructions.

It sounds like the neutral safety switch is going bad!

Hi Ronda
first you should not park your car on P position without you pull the hand brakes first, that's why you having problem pulling the selector out of Park.
regarding the starting problem, there is a switch on the transmission where the selector cable fit. It called inhibitor switch, this needs adjusting or replace in case is faulty
good luck.

I want to see if i catch your drift ! When you turn the key in the ignition switch to start , nothing happens ? Have you tried moving the gear slector to the neutral position to see if it starts then ? Park neutral safety switch problem , maybe .
Here is a description of how it works or how it's suppose to work .
Circuit Description (ECM/PCM Controlled)
Moving the ignition switch to the START position sends a 12-volt signal to the engine control module (ECM)/powertrain control module (PCM) Crank Request circuit. The ECM/PCM verifies that the transmission is in the PARK or NEUTRAL position. With the transmission in Park, voltage flows through the Park/Neutral position switch and feeds the starter relay coil. The PCM then grounds the control circuit of the starter relay. When the starter relay is energized it allows battery positive voltage to the starter solenoid S terminal. On some vehicles the starter will continue to crank the engine with the key released until it starts or the crank command has timed out to prevent excessive heat build up in the starter circuitry or the ECM/PCM receives an engine run flag.
Circuit Description (BCM Controlled)
Moving the ignition to the START position signals the body control module (BCM) that engine crank has been requested. The BCM verifies that theft is not active and sends a serial data message to the powertrain control module (PCM) requesting engine start. The BCM also energizes the RUN/CRANK RELAY. When the RUN/CRANK RELAY switch side closes, and the vehicle is in Park or Neutral or with the clutch is fully depressed, if equipped, supplies voltage to the starter relay coil. The PCM verifies the transmission is in Park or Neutral and the clutch is fully depressed, if equipped. The PCM will then ground the control circuit of the starter relay, closing the switch supplying voltage to the starter solenoid. On some vehicles the starter will continue to crank the engine with the key released until it starts of the crank command has timed out to prevent excessive heat build up in the starter circuitry or the PCM receives an engine run flag.

Test/Service/Replace

The circuit on newer cars with automatic transmissions has a neutral safety, or neutral start switch installed between the ignition switch and the starter. The ignition switch cannot operate the starter motor unless the transmission is in park or neutral.
Late model vehicles with manual transmissions have a starter/clutch interlock switch that requires the clutch to be depressed to the floor.
Neutral Safety Switch
Normal operations of a neutral safety switch provides a quick check for the adjustment of the gear selector linkage.

• To do this, move the selector slowly until it clicks into the PARK position.
• Turn the ignition key to the START position.
• If the starter operates, the PARK position is correct.
• After checking the PARK position, move the lever slowly toward the NEUTRAL position until the lever drops at the end of the NEUTRAL stop in the selector gate.
• If the starter also operates at this point, the gearshift linkage is properly adjusted.
• This quick test also tests the adjustment of the neutral safety switch.
• If the engine does not start in either or both of these positions, the neutral safety switch or the gear selector linkage needs adjustment or repair.

CAUTION
Since you must work under the vehicle to adjust most shift linkages make sure you properly raise and support the vehicle before working under it. Also, wear safety glasses or goggles while working under the vehicle.
A voltmeter can be used to check the switch for voltage when the ignition key is turned to the START position with the shift lever in PARK or NEUTRAL. If there is no voltage, the switch should be adjusted or replaced.

Sound like a problem with the Safety Neutral Switch, its possible that need adjustement. Keep in touch.

Hope this helps.

This could be the problem. If your dash indicator is showing reverse but the transmission is in park it could be the safety switch. I'm not talking about the safety switch in the transmission though. In automatics they put a second switch to kill the starter from engaging. You need to adjust the linkage. If your shifter isn't actually on the column but the indicators are there is a cable that attaches the floor shift to the column and that is adjustable. Put the Floor shifter in Park and turn the column section nearest the dash by hand until you find park. Then adjust the cable length as needed. If all you have is the column shift it is still a cable adjustment. Set the emergency brake, drop the shifter to low 1 and adjust the cable linkage by loosening it on the transmission and manually move it all the way to low 1 then tighten it down then move the shifter to park and repeat teh adjustment process to verify that it is properly aligned. Lock the linkage back down and see if the vehicle will start, if it doesn't move the shifter to neutral and try to start the vehicle if the vehicle starts then check the column shift safety switch at the park position to make sure it is still in place and working. Typically, if the vehicle won't start in Park or Neutral it is more likely to be the Transmission neutral safety switch.

The vehicle you have was made with a start safety switch,, it will only start in Park or neutral, sometimes that switch has just moved with normal wear and tear ,, and can be aligned again, but if its shorted or damaged it will need replacement, its located at the end of the shift cable located on the top of the transmission,

When you turn the ignition switch to start ,it sends 12 volt input to the PCM - engine computer . The PCM will then energize the start relay in the under hood fuse / relay distribution box.
Here is factory service info.
Circuit Description
Moving the ignition switch to the START position sends a 12 V signal to the PCM Ignition Crank Sense. The PCM verifies that the transmission is in the PARK or NEUTRAL position. The PCM then grounds the control circuit of the START relay. When the START relay is energized it allows battery positive voltage to the starter solenoid S terminal.

Try moving the gear selector to the neutral postion when it fails to start . To eliminate or confirm the park neutral safety switch as the problem . Are any lights lit on the insturment cluster ? Check engine , security ?

Try strating in Neutral. Maybe a bad Park-Neutral safety switch.

Usually neutral safety switches have asmall hole that a pin goes in, and then on install the shifter is placed in a position, like neutral, based on the switch positioning.

HOWEVER, I suspect that yours is installed, so I suggest plan B. FOOT ON BRAKE, turn key to on, move shifter into R.

Turn key to start, and slowly move shifter towards neutral.... Note exactly the shifter position when starter fires off, and release key, no start needed.

Then, do the same thing from Drive, move shifter towards N, with key in start position.

What you want is no start in either R or D, you knew that...And adjust neutral safety switch to "center" the starter actuation, preferably not until well into N, but that is not adjustable...

So, final is key to start position, test from Low, 2, d as you move shifter.... finally, you get start in N.

turn off.

Place in R, turn key to start and move towards Park, and you should have the starter fire off after out or R.

Hope this helps, that is what is involved.

Doc