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Remote Start, Push Start and Keyless Entry Install Write Up / DIY

118876 Views 120 Replies 22 Participants Last post by  Ride748
I am posting this as a follow-up to a few suggestions and support from my recent video post regarding the install of the keyless-go, alarm and push-start button in my 2005 ML350:

*I would like to thank warm_mt_dew for the advice and tips*

Along the process, there will be 'intersections' where I consider to be "fielder's choice" meaning whichever direction you decide to take from there is solely up to your preference(s) and/or reason(s). EX: You may be installing a regular remote start system instead of the pushstart, so take your path, accordingly. I have taken pictures of the parts I think are critical and would be informative, the rest will be mentioned in text.

Wiring diagrams/charts were taken from
'98 - '00 ML320:
1998-2000*Mercedes Benz*Ml 320*Vehicle Wiring Chart and Diagram

'99 - '00 ML430:
1999-2000*Mercedes Benz*Ml 430*Vehicle Wiring Chart and Diagram

'01 - '02 ML-class:
2001-2002*Mercedes Benz*ML Class*Vehicle Wiring Chart and Diagram

'03 - '05 ML-class (I used this chart):
2003-2005*Mercedes Benz*ML Class*Vehicle Wiring Chart and Diagram

***PLEASE NOTE***: Use the above charts as a starting point / general idea as well as my write-up. ALWAYS test your wires/wiring if uncertain. *I am not responsible for any "oops" because you didn't test any/or double check*

Handy things to consider having:
-> Wire cutter/crimp/stripping tool
-> Wire connectors (posi loks, electrical tape, solders, etc...)
-> Multimeter
-> Screwdriver, sockets (10mm), Torx set (T15 thru T27), flathead, philips,
plastic pry-tool, zip ties, etc...
-> Of course any installation instructions.
-> A note pad (in case you vent out some unique combination swear-words)

**The unit I bought came with an internal immobilizer relay/control and chip sense wires that doesn't require me to use an universal transponder bypass such as the DEI 556UW. If your unit does not have this function, then you MUST use a bypass such as DEI 556UW and follow the wire connection instructions under the section "THIS METHOD WILL WORK ON EUROPEAN VEHICLES"**

1) Remove driver's kick panel cover (philips and plastic screws by the pedals). The OBD connector will prevent you from moving the cover further. On the back of that connector, squeeze the pinch points and slide the clip/gate to free and pull out the connector.

2) Steering wheel cover: Loosen the 3 Torx bolts (T25 or T27) underneath the cover...2 on the sides and 1 on the back. Use a flathead to free up the taps at the crease lines where top and bottom covers meet. 4 taps total: 2 on the sides and 2 on the front (behind the steering wheel).

3) Remove the 2 small panels on both sides of the steering wheel (just pull them out with adequate force). You will see the ignition connector and wires:
Auto part Vehicle Car Engine

4) Remove the Immobilizer box by sliding it towards the ignition wires.

5) The immobilizer coil is encased by the black plastic housing, clipped onto the keyhole. Use a flathead to lift/pry it off, it should pop out easily. Wondering why is there a blue Posi-lok wire connector? That is because I had to undo my installation in order to take the "before" pictures. You will see later in the process that I will be connecting the ends of that wire to the onboard bypass control
Audio equipment Auto part Technology Electronic device Steering part

6) The Ignition switch connector is held in by TWO tabs/clips (top and bottom):
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7) After referencing the wire colors to the wiring chart for my year range and a bit of testing to confirm, I was able to identify the wires and in the pin slots below:
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8) The Keysense (Orange) wire: This wire normally does not have 12v going through UNTIL a key is inserted. What I did here was cut the Keysense wire and connected it directly to a 12v source, through an On/Off rocker switch. This is to trick the car that there is a key inserted, otherwise, it will NOT remote start. I put in the On/Off rocker switch so that if I need to open the driver's door for some time, I won't be annoyed by the "key still in ignition switch" reminder beeps. This can also come in handy shall I need to perform any syncing sequences that would normally require me to 'remove the key' as part of the sequence. I tried to hook this up to the remote start unit's IGN 1 wire but it didn't work. I have not tried the ACC wire though, which I think it might work.
*UPDATE!* Connecting the Keysense wire to the ACC wire from the remote start unit worked!
Wire Electrical wiring Cable Cable management Electronics accessory

9) This picture just shows some of the preparations that I did on the remote start unit. The Purple and Green wires (top right) will be connecting to one of the immobilizer's wires. Since the ML only have IGN 1 wire and ACC wire (no IGN 2 wire), I combined the unit's IGN 1, IGN 2 wires and connected those with the ML's IGN 1 wire.
Wire Technology Electrical wiring Electronics Electronic device

10) Here, I cut and connected each ends of one of the immobilizer's antenna wires to the unit's onboard immobilizer control Purple and Green wires. (TEST time) After doing this, I plugged the ignition switch connector back in and the coil ring back onto the keyhole, keysense wire connected to 12v (as explained in previous steps), inserted a working factory key, tried to start the engine like normal but it did NOT start. I then removed the key but held the chip side of a working spare key close to the immobilizer coil, pushed the Push-Start button and the ML started right up. This tells me that I can safely attach and leave the chip part of a spare key at all times with the ML and not worry about somebody 'hot wiring' to start. If they can find the wires...:D
For those using an universal bypass module (DEI 556UW), there is a wire connecting diagram in the manual, under the section "THIS WILL WORK ON EUROPEAN VEHICLES". You will end up doing the exact same thing like the picture below. The ONLY difference is that your "sacrifice" key will be left inside the bypass module's box, instead of attaching it to the immobilizer's coil. The DEI 556UW bypass will also need to be connected to: 12v+, ground and starter status output from your choice of remote start unit. I did not use the DEI 556UW because my unit does not have such starter status output but is replaced with an onboard control/relay. I hope this made sense!
Technology Electronic device Electronics Wire Cable

11) This shows how my spare key is attached to the coil. I am embarrassed to show this pic because I tried to cut the key blade but failed miserably (this is why I suggested a note pad for cool and unique combination swear-words!). Cutting the key blade serves the purpose of bypassing the steering wheel lock, since that I am installing a Push-Start. This is where that "fielder's choice" comes in. In order to bypass the steering wheel lock, you'd need to insert the key blade and turn to ignition ON and leave it there (like forever). This means that if you also have the Ignition connector plugged into the switch, you will constantly have the accessories on (BATTERY DRAIN!). The "fielder's choices" are: completely and permanently unplug the ignition connector (while keeping the key blade in the ON position to constantly bypass steering lock) which is what I did, OR, cut both Ignition wires + the immobilizer antenna wire that was tapped and connect to On/Off switches (and leave it in the OFF) so that you don't drain the battery. This gives you the flexibility that in a case where you need to start your ML with the key it'd work. And yes, HIDE them switches! Did I lose you somewhere? More combination swear words? COOL! IGNORE THIS STEP IF YOU'RE JUST INSTALLING A REGULAR REMOTE START (non push-start).
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Continue shortly.
12) Connect the unit's remote start wires accordingly to the ML's ignition wires. After that, the wires are hidden away. The potential prowler will first have to find the wires and then realize a few other components are also hidden...
This is a "fielder's choice" as mentioned earlier! I will soon or eventually switch back to have the Ignition connector plugged back into the Ignition switch, and will have On/Off switches (hidden away) to manually activated/deactivate current flow, should I come to a point where I will need to use the key.
Auto part Vehicle Car Engine Automotive exterior

If they decide to stick around way longer than anticipated, then this might happen...
Auto part Vehicle Audio equipment

13a) Brake wire: I do not have a brake switch above the brake pedal, so to the fusebox I go.
Auto part Engine Vehicle Car

13b) Pull the tabs and lift the front cover, then the Torx bolts are exposed:
Electronics Technology Electronic engineering Electronic component Electronic device

13c) Once all the Torx bolts are loosen/removed, lift up the back cover to expose gazillions of wires AND a firewall pass-through hole:
Auto part Trunk Technology Automotive exterior Bumper

Closer look with the foam removed:
Auto part Wire Tire Trunk Automotive tire

13d) A shot from inside, underneath, top left of the brake pedal behind a rubber-cushion flap (next to the plastic vent hose...?).

14a) Brake wire happens to be in this connector:
Cable management Electrical wiring Electronics Networking cables Technology

14b) Presuming I found the right connector per the wiring chart with pin #2 being the brake wire, my testing (with Ignition ON) showed that it wasn't pin #2 but a different pin (forgot the number):
Cable management Wire Networking cables Electrical wiring Electronics

***I would stop here to test the remote start function to make sure it works, before moving on to the other components!!!***
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15) Door trigger wire: Mine is located at the AAM which is underneath the fuse box. Reference your year to the chart, accordingly (AAM, Keyless Module, etc...). For 2003 - 2005, the domelight supervision wires are also located in there, but in a different (black 6-pin) connector.
Wire Electrical wiring Cable Technology Electronics

16a) Parking lights/blinkers: located in the headlight switch which is under the steering wheel, held on by a bolt with a 10mm head. Loosen bolt, pry up the connector cover clips (3 front, 2 sides).
Auto part Automotive lighting Automotive exterior Vehicle Headlamp

16b) Pin #4 (Green) = Right blinkers.
Pin #6 (Blue) = Left blinkers.
Wiring chart says to use 775 relays.
Wire Technology Electrical wiring Electronic device Electronics

17a) Door Lock / Unlock: Pull or pry up the shift trim:
Metal Gadget Mobile phone

17b) *Turn ignition to ON and shift gear lever to Neutral*
Remove the screws from the center compartment lining so that you can lift it up (you won't be able to completely remove it without removing other parts) to expose the center console's 2 Torx bolts (T20 or T27). Once the bolts are removed, the center console can be lifted (with a little force). You may also need to lift the compartment lining so that the console can clear through.
1998 - 2002 models: I think you can completely remove the compartment linings and just pull up on the window/lock control console
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17c) Once the console is lifted, the connectors are exposed. Press the tab and pull the gray lever down to release the connector:
1998 - 2002 models: I believe yours have a fourth (small) connector which contains a separate wire for UNLOCK
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17d) Press the little tab to unhook the single connector (mine happens to be black):
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17e) Use a flathead to push the single connector out of the housing, from the rear:
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17f) 2003 - 2005 models: There is only ONE wire (-) for Lock & Unlock. Pin #25 and it's either PINK or WHITE. (Mine is Pink).
Connect a 470 Ohm resistor (Radio Shack, $1.19 for a pack of 5, LOL) between the LOCK wire from unit and connector. The UNLOCK does not require a resistor. MAKE SURE YOU TEST IT, in case it's backwards. If so, then just switch the resistor from the LOCK to UNLOCK.
Wire Electrical connector Electronics Technology Finger

17g) Run the wires as you please.
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Thank Man Great post & DIY Cheers _PTEngineering
Thank you! :beerchugr:
You should append this to the DIY section...just in case. Simply post a link to this thread in there.

Thanks for the writeup
Will do! Thanks.

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Yes, good stuff.

It is recommended to hard-solder your connections instead of the taps you have used though.

The taps have a tendency to vibrate and move. Over time there can be loss of electrical contact and high resistance to current flow. The remote starter can do some pretty odd stuff and even prevent you from starting with your push-to-start.

But at least you still have your switches to use the key if required.

Professional installers will not use such connectors.

Just a tip.
Good tip, thank you!
I will solder once I learn how to. Lol

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Thank you for this DIY! Complete this recently, so now it runs on my ML320, 2001 as well.
Glad to know!
What brand/model did you install? I'm thinking of installing a different system with a longer remote start range. The range on the current system sucks.
Arctic Start

I followed Most of your instructions and found them very Helpful. I used a Arctic Start single button touch Fob, Model AR-601S and a By pass module from Mid City Engineering. I was more interested in the REmote start (part) so I chose the Cheapest kit Arctic Start has. $60.00. I did not want the OEM Locking system & Security system to be the Slave to The remote start . I needed something My G/F could use . The OEM key tumbler & switch with the steering lock were just to hard for her to turn over the the Cranking postion. So I used your Key switch wiring set-up Brake Light , running lights Hook up. I also had to change the crank from a TIME based , over to where it would read rpm . Seems that the MLs 98 - 05, have a long Crank period than other cars. If I were to do it again I would use a more advance Kit , (multi button touch Pad) so I would not have to press the single button Fob twice. other than that . I can remote crank up to 800 feet away But have to be within 10 feet to unlock it !! LOL Thanks again _PTEngineering
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The remote start range on my system is such a joke that by the time I activated and it actually crank, I could've hopped in and said a swear word. hahaha.
Auto Start

Arctic Start is under Firstech, LLC along with The higher end Brand, Compustar The easy / entry Level Models of Arctic Start can go to 1000' AM Freq Then has other models to 1 mile on 900 MHz FM
But The most inexpensive one I got does what I wanted at minimum cost
Cheers _PTEngineering
Great post
I might fit one of those,to unlock all my doors i have to press my remote twice can i change that through the AAM before its fitted so all the doors unlock on the first operation.
I believe hooking up the Lock/Unlock wires from the center console will lock/unlock all doors with a single press.
Ordered it today so ill try and hook it all up in the next couple of weeks and see how it goes. Your post will be off great help you have put a lot of good detail in there. Thanks:thumbsup:
I look forward to knowing how it went!
Any issues, tips, alternate (better) ideas would be great.
I'm thinking of upgrading to the Advanced Keys system or one of the Viper/Python systems...soon.
Got it all hooked up today and yes it was a whole day. CGL post was off great help locating all my wires as the instruction that came with the unit were very generic. My truck being a 99 model some stuff was a little different but with a bit off testing and swearing i eventually worked it out. I pulled the chip out off my broken remote key and taped it to the outside of the key recognition ring,that seem to work well. Hooking up the door locks to the centre consol switch made all my doors open together,(thanks again CGL). Nutting out the steering lock was the hard part because i still wanted the option of starting the engine with the key. (Just in case). Had to cut the acc and orange key wire of back of my ign plug and then put a screw through the top off the barrel where the steering lock clicks back after you take the key out to stop it clicking back and locking the steering .If that makes any sence. The reason i cut the 2 wires of the plug was the acc stays on until you pull the key so i had to trick the computer to think the key had been pulled out. Doing it this way i dont have a steering lock, but not to concerned. If i do start the car with the key i dont have acc, But this is only if the push button dose'nt work for what ever reason. Over all im happy with the way it all works and my start button fitted next to my gear shifter really neatly.The effort that you guys go to with some posts makes doing these sort of DIY jobs a lot easier. THANKS:thumbsup:
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