MikeBuzzsaw

Under my 2013 GL450 there is a MBUSA factory tow hitch receiver, but I could not find the wiring harness for trailer brake lights. Is the wiring harness not included from the factory?

fabbrisd1

If the factory hitch was installed at the factory - the spec sheet will show that - yes, included the wiring.

If the hitch was installed at the dealer - and the owner did not want/need wiring - then yes, the dealer could have installed the hitch w/o wiring harness.

If you just need "standard" wiring - then any U-Haul can add wiring connection for you - using Modulite module.

Keep the beat !

MikeBuzzsaw

On my the original window sticker it shows:

"Electronic Stability Program (ESP) with ESP Trailer Stabilization"

Underneath, there is a hitch but no connectors. I'm a bit confused because anytime I've owned a factory installed hitch, there already a connector installed.

For the 2013 GL450, what's the part # for the harness and do I need the dealer to program anything? I do not want to do any u-haul options.

lingaraju.g

look to the left of the receiver u will see a sqaure plastic thingy with a cap and it contains the wiring, atleast thats how it is on mine. i dont know nothing about u haul option.

Isawelvis

Looking at your hitch, the hole to the left of the receiver is where Mercedes normally has the electrical contacts for the hitch. Either it has fallen out, or like said in an earlier post, the owner just had the hitch installed without the electrical connection. I have done this on several of my cars, since I only use it for a bicycle rack or during daylight towing of my utility trailer.

If possible I would get someone to run your VIN number and it would have if it had the trailer option from the factory.

You have a couple of choices if you need to get the electrical installed, either buy; a electrical kit from the dealer ( which I did one time) and had the dealer install it or go to a store that does recreational vechiles and have them install an after market one. I did that on my last two cars.

MikeBuzzsaw

I appreciate the thorough answer! I did buy this car used and the original owner stated the hitch came from the factory. Going off that, I figured the hitch should already come with electrical socket (where the left hole is). But there's nothing there.

Do all the GL450 with the factory installed hitch option come standard with electrical connections (where the left hole is)?

I guess I have to make an appointment with MB to get the bottom of this.

MikeBuzzsaw

http://r.ebay.com/oby8TD

I think I need this...?

srfrboy

From the picture that you have attached, it looks like the wiring harness was never installed or removed. It has the plate, just no wires and harness.

fabbrisd1

Let me try to clarify for you:

1. If the hitch was installed at the factory - it would be listed as "Trailer Hitch" under options - and would include the factory wiring harness including connectors at the back

2. Yes - in your rig the ESP does have Trailer Stabilization - IF the trailer hitch was factory installed OR if MB hotch was dealer installed including wiring harness (big job)

In your case - from what you say - and from what the owner you bought it from - YES it sounds like you have a MB dealer installed but without the additional expense of installing the factory wiring harness.

Frankly - if you just need basic trailer wiring - any U-Haul store can clip that it - with Modulite relay - etc..

wally AMG

Most people think that trailer hitch with a tow ball to haul is enough, well if you are planning to move a small 7x8 trailer with a sod cutter is not a problem otherwise hook a trailer, travel trailer or a boat to your GL connector is very important not only for the trailer lights, it is important because the GL will adjust the brakes it self, will adjust the airmatic / air bags, will adjust the lane keep assist option, basically the GL will recognize that is a trailer behind and will adjust settings for your safety, sometimes people try to save a few $ but in exchange will have a $1000 + air matic shock damage. Get a Wiring harness is a smart decision.