Technical 500X Cross Plus Towbar Fitting

Currently reading:
Technical 500X Cross Plus Towbar Fitting

Joined
Dec 5, 2006
Messages
5,932
Points
1,494
Location
Wrexham, North Wales
Well I've just fitted the tow bar myself and thought I would give the relevant info here for anybody else thinking of fitting one themselves.

I took my time over this (two days) as I want to go slowly and steadily and very carefully due to required trim removal and wanting to do a better than professional installed job.

A) General bumper description. This is essentially a one piece part for the purposes of removal. Unlike other Fiat bumpers I've removed there are NO bolts inside the boot area/wing that secure the bumper sides to the rear wing/quarter panel. This makes the bumper removal rather mysterious. The whole bumper top sides and back surfaces are clipped into plastic retainer/carrier plates that are pop riveted to the bodywork!

Steps:

1. Disconnect battery. Do NOT remove battery negative terminal from the battery but instead the earth cable via the push button. This is important as on the Cross Plus there is a sensor system built into the negative terminal plate. See your User Manual.

2) Remove both rear lights as per User Manual. One the two retaining screws are remove make your hands dry/sticky or use rubber gloves to pull the lights out backwards. The outside edges of the lights are secured to the bodywork via a "dome/ball head" pin/bolt the pushes into a rubber socket on the car bodywork. Can be tight/fiddly to separate. Do not attempt to swing light unit out to side

3) Remove the 3 self tapper screws in the N/S and O/S wheel arches. These screws secure the rear lower part of the wheel arch liner to the bumper. Use a short stubby screw driver. No wheel removal required.

4) Remove the 4 bolts on the underside of the bumper that secure the bumper bottom edge to car

5) Remove the 2 bolts (1x N/S & 1x O/S) that secure the top of the bumper either side to the bodywork.

6) Now come the tricky / delicate part. The N/S and O/S top leading corners of the bumper are secured to the wheel arch panel via a M6/M7 self tapping bolt (might be M5 head). If you look carefully inside the wheel (through a cut-out in the liner) are you will see the white retaining clip with the bolt going through it. Do NOT try pulling, levering or bashing from inside the arch to see if these fixing will pop out. THEY WILL NOT and you will only bend/distort the bodywork. To gain access to the bolts you need to VERY carefully prise off the black plastic wheel arch/wing trim. Please read 7) very carefully!

7) You do NOT have to remove the whole trim. You only need to remove the trailing part to gain just enough access to get a flat ring spanner on the bolt head. The WHOLE trim is secured as follows. At the front leading edge it is taped and BLUE trim button mounted to the wing. In the middle it is BLUE trim button mounted to the wing. At the position towards the rear where the trim is just about to leave the wing metal panel area it is BLUE trim button mounted to the wing. THESE BLUE trim buttons are a) VERY fragile and b) very special in that they are double injection moulded with built in rubber washer/cushion. I've never seen this type of trim button fixing in any car store etc. so will only be available from Fiat. Strongly suggest to get some spares before attempting to remove the trim. The rear edge of the trim where it overlays the bumper is secured by 4 green trim fixing buttons. 2 one above the other at start of bumper run and 2 one above the other at end of bumper run. BEFORE attempting to gently prise the trim buttons out (please use a proper trim removal tool) place a small G-Clamp over the trim between the 2nd and 3rd BLUE trim fixing buttons. You will only need to pop the 3rd/last BLUE button and the G-Clamp will protect the other two from being broken or disturbed. Additional tip is also move the wheel arch liner in/up/away slightly so you can put a some WD40/lube on the button bayonet heads and also gently push from behind whilst levering.

8) Remove the 2 leading corner self tapping bolts

9) Now for the "Be careful, Be brave step" :D The carefully inspect the bumper top edge all the way round. You will see that the sides just appear to be still firmly secured to the wing and will not move backwards/forwards or down. This is because they are "snap clip" retained in a black carrier plate. Firmly grab the leading corner of the bumper where you have just removed the screw and gently but firmly pull the corner directly outwards. Makes a horrible sound but it will unlatch and flop loose. (note the 3 latches). Do the same for the other side. (you could try some WD40/lube along the top/in interface recess if you experience any undue resistance)

10) Release the latches (2 off each side) that secure the bumper boot top corners to the black plastic carrier plate. Bumper will now finally want to come off so be ready AND WATCH OUT for the parking sensor cabling/connector which has to be separated before the bumper can be finally removed.

To fit the tow bar is dead easy. All the required holes, mounting points are already drilled and filled with blanking plugs which you just remove. Just follow the supplied instructions. My tow bar was a Brink detachable but I've read the instructions for WestFalia and GDW and they are all pretty much the same.

Pumper replacement is just the reverse process. THREE IMPORTANT points to note. 1) Ensure the parking sensors are connected and check each one before fully refitting the bumper! 2) When the bumper came off there were two foam buffer pads that sat on top of the rear crash bar. I refitted these with clear silicone sealant so the extra buffer/support is retained. 3) When putting the bumper back take great care to ensure the rear top edge of the bumper along the boot line actually fits into the carrier plate and not over the top of it. If you miss this then the sides will still latch in but the other rear corner latches will barely latch and the bolt holes will not be fully aligned. If this happens then you will have to be brave again :eek:

Wiring:

I personally chose not to use a dedicated wiring kit as this has to be routed through the car requiring cabin trim removal and fiddling around under the dash etc. Even if you fit the dedicated wiring kit (which is expensive) it will only cater for trailer/caravan lights. They do no support caravan battery charging and fridge etc. so one will still have to do this as well. I used the standard AND REQUIRED 7 way bypass relay and voltage switching relay. The disadvantage of using a bypass relay is that the parking sensors will not be disabled. No big deal IMHO. I'm also pleased to note that with the detachable swan neck tow hook attached to the car the reversing sensors DO NOT detect the hook. (y)

With the Brink tow bar then the foldaway 13 pin socket when wired with a normal rear entry socket WILL NOT fold up. I also suspect that this will be true for other approved tow bars. The reason for this is that the socket plate is only 15mm to 20mm away from the rear valance metal work or the car. One could cut some metal to get around this but I chose not to. On speaking to Brink they supplied me with a cable side entry rear socket cable gland but to fit this one has to also make an accurate corresponding semi-circle cut in the side wall of the socket. Even then one would have to bend the wires immediately at the terminals which I think will be very very tight and may still be a problem. The company that supplied the tow bar also kindly made extensive checks with various 13 pin socket manufacturers and nobody appears to make side entry sockets.

To get the two power feeds and the 13 way cable into the boot of the car you can use the cable entry gland on the O/S which carries the parking sensor wires. This shaped/booted gland can be carefully cut up the cable "tail" to open the tail out and get the wires through. Wires all point downwards so water ingress won't happen but for extra integrity I used self amalgamating tape to finish off with.

Power Feeds: Minimum 2.5mm square cable rated at 35Amps. Two feeds taken from battery +ve terminal connection plate un-fused terminal post. Immediately fuse each feed with 15Amp fuses. Run cables to bulkhead, across bulkhead to far left corner (as you look at car). Follow fuel lines down to underside of car. Remove trunking cover plates and lay wires. At end of trunking route wires up over the rear suspension, up in/alongside spare wheel well and exit to rear O/S corner and into parking sensor cable gland.

I used flexible cable trunking across the bulkhead and up over the suspension to rear O/S. Elsewhere I used spiral cable wrap and heat shrink sleeving and this attention to detail, including planning/thing cap time is why I took my time over two days(y)

Car Light Wiring: (note 500X Cross Plus 1.4 Multiair II - no reason to but may be different on other 500X models)

RHS Side Light -- Yellow/Black --> ZR2500 Brown Wire
RHS Fog Light -- Brown/Yellow --> ZR2500 Blue Wire
RHS Indicator Light -- Blue/Black --> ZR2500 Green Wire
RHS Brake Lignt -- Green/Yellow --> ZR2500 Red Wire
RHS Earth Light -- Black --> ZR2500

LHS Side Light -- Yellow/Red --> ZR2500 Black Wire
LHS Reversing Light -- Purple/Green --> ZR2500 White Wire
LHS Indicator Light -- Blue/White --> ZR2500 Yellow Wire
LHS Brake Light -- Green/White --> ZR2500 no connection
LHS Earth Light -- Black --> ZR2500 no connection

Before tapping into these wires completely unwrap all the electrical plastic and cloth tape to ensure you have plently of room to make the connects as far up as possible in the cable looms away from the rear lights themselves. This will allow for easier connections AND repairs should they ever be required.

Finally, to get access to the car wiring and install the units some of the rear internal trim / fittings have to removed or partly undone. These are:

1) Rear central back trim - 4 screws and then lift/pop off trim button
2) Side trim - large plastic push rivets and lift/pop off trim buttons. Note this trim goes from the boot floor/side all the way and includes the parcel shelf support sides. You only need to release the lower corners and vertical sides of the trim to be able to release the side panel carpet
3) Side Carpet has top corner plastic buttons to remove
4) Boot raised floor support brackets on N/S & O/S
5) Cargo strap eyes next to raised floor support brackets

If you do ever fit a tow bar then I suggest you did what I also did. I miss the rear power socket my Croma had so I took this opportunity to add a four way power socket on flying lead that neatly resides in the under floor boot storage area. With a 35Amp cable feed I changed the power feed fuse from 15Amps to 25Amps and then used a 10A fuse in the 4-way power socket lead.

Good luck!
 
Update Information

It now transpires that the 500X brake and sidelights are multiplexed.

This means that if you use a PCT ZR2500 unit there is NO NEED to connect the side light signal wires as detailed above.

With the above wiring then the towed vehicle/trailer side lights work OK as do the brake lights HOWEVER when the brake lights are activated the towed unit's side lights will also come on.

This mode of operation is perfectly legal and not an MOT issues but some purists might like just the brake lights to come on.

For me I'm leaving the system as is because when the brake lights are operated all my caravan red rearward facing lower and upper corner marker/side running lights also illuminate giving increased brake signalling during the day.
 
Last edited:
Back
Top