Electrical Weird Electrical Issue with connecting to Jeep.

[Lukemac]

Hello Everyone,
I'm hoping someone can point me in the right direction.

I just purchased an Expanda 17.56 OB 2015 (LED Lights) and plan to tow it with a Jeep Grand Cherokee Limited diesel 2015.

Had a Tow-Pro Elite installed which seems to work ok.

When I connect to van to the car some weird stuff happens.
The Van has 7 pin flat plug and two Anderson plugs, one for battery and one for the Fridge.
With the van connected all the running lights, indicators and brake lights work.
But I initially lose power to the front windows and the Uconnect system takes 15 seconds to boot up, instead of being an instant boot and I have no volume on the radio or can't change any of the climate controls. Once the Uconnect system boots, I get power back to the front windows, but nothing else.

As soon as the van is disconnected everything goes back to normal.
I tried disconnecting the tow pro with the same result. So I don't think it anything to do with that.
I've tried starting the car first and then connecting the van, with the same result, the moment I connect the van the UConnect system wigs out and doesn't respond.
I connected up my 7x4 box trailer and it all works ok without the Uconnect issue.

I'm thinking it some kind of grounding issue with the van?
Can't say electrical systems are my strong suit, can anyone suggest a fix or where to start.
I will take it to an auto electrician but want to try and have some idea of what's going on first.

Thanks for helping out.

Luke

 

[chartrock]

We have electrical experts and Jeep experts here so help should be available fairly quickly. Welcome to the forum.

 

[Drover]

Most lights and stuff gets turned on by the BCM so anything connected old style will throw things out, now you never wire a pick up to a light or switch.

I would be looking at how the Tow Pro is connected and how the power is drawn for the fridge supply Anderson, so long as all the van clearance lights and the parkers on the Jeep are working when the van is hooked up then thats one possibility out of the equation.

Ideally the Fridge Anderson should be drawing from the battery jumper terminals under the bonnet with a fuse/breaker set up.

If it has a Jeep tow pack fitted it should be connected to all the right things so I'm still suss of the Tow Pro, it should be drawing power from either the fuse box under the bonnet RH side or fused from the jumper points, earth to body or jumper, 2 wires from the Tow Pro should run down the back to the cargo area, lift the pod pocket on the LH side( thats under the torch mount ) you should find the connector where the tow harness plugs into the vehicle wiring, coming off this should be a plug with a blue wire (brake connection to 7 pin) and a red wire which is the brake light which activates the controller, if they have wired it directly to the 7 pin thats not a biggy but if they have the activation wire coming off the brake pedal switch under the dash or off a wire other than one on the tow harness then thats whats causing the drama, the activation wire must come from the tow harness brake light connection, anywhere else the BCM has a big hissy fit.

Write ups about connecting to under the dash don't apply to Export models only USA models have the harness under the dash. Most vehicles nowadays the safest way to connect brake controllers is to draw the brake activation from the stop light wire in the 7/12 pin as this is from the tow harness package and doesn't cause BCM's to see unknown power draw....................

If not then I would plug in van but have everything bar the clearance lights connected and if they work then connect each one back up till I find the dodgy set up.....

Its not a Jeep Thing either any vehicle that runs on a Canbus system will do the same, when buying replacement led globes go for the ones that are supposedly Canbus friendly.


Just re-read your post I'll take a stab at power supply pick up for the Tow Pro, they tapped a live ignition wire under dash or wrong terminal in fuse box... then again could be totally wrong..............

 

[Lukemac]

Thanks for your suggestions.
The problem has been Solved.


The #2 pin which on most trailers is the reversing light, but on a Jayco caravan is a 12v battery charger.
Somehow this was feeding back via the ground back to the car.
I spoke with the Auto electrician this morning and he suggested pull the #2 plug wire out and now all is as it should be.
Check lights brakes etc and all is good.
I had the dealer change the plug over from 12 to 7 pin, it may not have been previously connected give the battery has its own Anderson plug for charging.

Thanks

Luke

 

[Drover]

That would be why the boat trailer didn't show a fault................. often the 12v power to van will run both charge and fridge so if they connected pin 2 that certainly would have thrown the BCM into a wobbly as it would more than likely still be connected......
If you had said to us you had the dealer change the plug We all would have said check the plug !!!! always the obvious place is where they last touched something.
Glad its now all sorted.............