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I am new to the forum and a new owner of a 2014 E350 Cabriolet. I am looking at installing my ALP Priority Laser Jammer and Radar Detector system, which is a remote head installation. I had this is my past vehicles and have done all the installations myself. The biggest issue to solve in these installations is how to get from the engine bay into the cabin of the vehicle via the firewall. As I am not as familiar with this vehicle, I am hoping someone has had success (and advice) on how to route the cables from the engine bay into the cabin.
in looking through the engine bay, I found a round plug (hard plastic grommet/plug) just below the battery and towards the center of the vehicle, which looks promising. I have attached photos below for reference. I plan on taking apart the underside of the dash and the glove box to see if there are any potential access points. The passenger side is always preferable to me. So any advice or recommendations would be greatly appreciated.
I have read that some have used access from behind the fuse panel on the driver side of the engine bay for routing other wiring, but that area seems tight for 3 to 4 larger wires needed for the ALP system.
So I managed to do my installation this past weekend. All I can say is that the engineers at Mercedes Benz like to over complicate things. The simple things are not.
I wanted to share the results in case this helps someone with a similar car. 2014 E350 Cabriolet (A207).
The electrical was also a pain. The fuse panel on the Driver side panel is all 12V constant, so not switched. The Cigarette lighter is impossible to get to in this car without removing the entire center console. So I routed a power cable from the passenger footwell side, to the drivers side, and up into the engine fuse box (easy to get through from inside the car) and tapped into fuse # 9, with the non-descript identifier of "Socket" per the fuse document (hidden in the trunk of the car). I believe this to be either the Main Cigarette lighter fuse, or the one in the back seat. The document shows 2 fuses for the "Socket", one in the Engine Bay Fuse box, and the other in the Trunk Fuse box. I used a Fuse Tap and made sure the polarity (hot side) was correct so that only one fuse blows in case of a short circuit.
The hard plastic grommet that I removed is actually a molded cap. I used a Dremel tool to hollow it out and then used a rubber grommet on top of it so not to chaffe the cables. It plugged back in nicely, since the hole is not completely round, and made a perfect sung fit. (I forgot to take a picture of it after I routed the cables)
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Picture of Firewall hole from the engine bay view.
Picture of the Firewall hole from inside the passenger footwell view. This is behind the footplate on passenger side.
Partial view of the hole as it is behind the blower assembly inside the car behind the glove box.
Kickplate under carpet on passenger side. Just 3 bolts hold the kick plate in place. I hid all the electronics behind this plate, and left the USB cable visible (and tied off), for easy updates in the future. The ALP Priority speaker is tucked away under the carpet in the top left of the picture. The floor carpet just folds down for easy access. A note of caution. There is a thin Orange Cable clipped to the kick plate on the bottom right. I found out that this is a Fiber Optic Cable and damaging this will be painfully expensive.
I am glad I did some research first. So be very careful with this cable.
Front view of car with locations of all sensors. The Radar head is behind the grille.
All Laser Sensors are level and straight. Another PITA thing to get done right.
TX Only Head Placement.
Radar head from above view.
Placement of the control pad. This was a real PITA to do as I had to remove the AC duct, the Radio/Command Module, and the AC Control module to route the cable.
Hopefully this will help and inspire those brave enough to take apart their overly-complicated Mercedes Benz vehicle.
Cheers....
Last edited by mercadof; Aug 31, 2018 at 08:42 PM.
Don’t know if this will help anyone else, but I had to run a cable for a front camera to an Android head unit in my e250d UK RHD today.
Information in the thread was helpful. Here are some more details-
The black plastic blanking plug in the firewall is located to the side of the bottom of the battery. You’ll need to remove the battery to gain access.
The blanking plug has a square spline in the middle and is marked with an arrow, but this is largely meaningless as it has no corresponding mark to align it with.
Obviously, the idea is to rotate the square spline, with an open ended 10mm spanner, so that the locking mechanism aligns with the keyway in the bulkhead. In practice, it’s impossible to align, there’s no space to work and the centre spline breaks off after a few attempts.
Additionally, the plug has several teeth that clip into the metal bulkhead.
I ended up forcibly levering the plug from the engine bay, whilst someone inside the car squeezed the clips together.
In order to access the hole from inside the car, remove the plastic trim directly under the glove box (same panel which you remove to change the cabin filter). It’s held by three torx screws. Fold the carpet and soundproofing down to aid access. The hole/back of the blanking plug can be felt by placing your hand up the back of the glove box.
Have someone gently tap on the plastic plug, from the engine side, so that you can confirm you have the correct plug on the inside.
I broke the plastic that is meant to align with the keyway, but the plug was salvageable.
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