Witter Towbar Fitting: Step-by-Step
A step-by-step guide on how to fit a Witter towbar - correctly!
While we don’t expect you to fit a towbar yourself, it’s always good to know what the job involves and what the key questions to ask are when choosing a towbar and a fitter. After all, knowledge is power!
We took a Mazda CX-5 SUV down to Witter HQ near Chester to have a detachable towbar fitted. Technical Services Manager, Malcolm Parry, took us through the entire process:
(NB Malcolm’s so good that’s he’s been promoted since we shot this feature!)
1. Check the fitting instructions before you start
2. Remove the interior boot trim for access to the electrics. Some cars need the rear bumper removing for a towbar fit. The Mazda CX-5 doesn’t.
3. Check the new towbar and lay it out ready for fitting.
4. Ideally, raise the car on a lift for easy access.
5. Bolt the main towbar brackets to the current bolt-holes in the ‘subframe’. Some of these may be sprayed over with sealant/sound deadener and will need cleaning off.
6. Now fit the main towbar ‘beam’ across the back of the car. This bolts to the fitting brackets and sometimes replaces a crash beam, behind the car’s bumper.
7. Fit all bolts, torque-wrenching them to the correct tightness.
8. The ‘housing’, to which the removable 'swan neck tow ball' attaches, can now be bolted to the main towbar ‘sub-structure’.
9. Malcolm torques the swan neck towball to the correct tightness.
10. The towbar is now in place. All approved towbars will have a sticker something like this on them. Beware of very cheap options.
11. Now, fit the electric socket holder to the towbar
12. The mechanical part of the fitting is almost done. Now it's time to install the wiring.
13. Malcolm can now fit the 13-pin electric socket. It connects to the car’s wiring loom inside the boot and is fed out through an existing rubber grommet, to avoid further drilling. Malcolm seals the grommets with silicone as an extra defence to water ingress.
14. The cabling is carefully concealed behind the bumper and then attached to the socket holder.
15. The main cable has to go to the battery or fuse box under the bonnet, so Malcolm plans a route, and then pulls the cable up into the engine bay. He doesn’t connect it yet.
16. Malcolm then runs the cable into the protective trunking for extra safety and longevity. The Witter focus on detail is impressive through the 'fit'.
17. The cable and trunking are then fed along the underside of the Mazda and carefully cable-tied behind the protective undertrays.
18. The undertrays are bolted back in place.
19. The cables are run up into the boot space through an existing hole with a rubber grommet. Using existing holes means there’s less likelihood of rust getting into the bodywork.
20. All the connections are made, following the instructions. The towbar system now links into the main wiring loom.
21. Malcolm runs a wire forward inside the car to the internal fusebox concealed below the A-pillar. The fusebox has a 15A fuse. The cable from the engine bay fuse box requires a whopping 40A fuse.
22. This box is an electrical relay designed to activate the caravan’s indicators. It sits behind a panel in the boot.
23. This unit is a voltage control module (VCM), which supplies power to the fridge, and switches off at preset voltage levels to prevent the tow car's battery going flat.
24. Malcolm attached the engine bay cable to the battery/fusebox.
25. All the boot cables are carefully and neatly secured in the boot.
26. Almost done. A Light Mate test unit is attached to the 13-pin socket to check that all the caravan lights and facilities are working.
27. Finally, the boot panels are carefully re-fitted to conceal and protect the new towbar wiring.
28. All done! An elegant job with no bumper cutting required. The removable swan neck and be locked in place or quickly removed and stored in the boot.
Car and caravan electrical systems have increased in complexity massively over the last decade or so, which means you now have two basic options when choosing a towbar and electrics – one that bypasses all these smart systems and one that utilises them (like this one from Witter).
Clearly, the latter is the better option regarding safety and security, but it does come with a higher price tag. We think it’s a great investment, but if cash is tight, bypass systems will work just as well in almost all circumstances.
Whichever you choose, what is essential, is getting it properly fitted, ideally by an NTTA accredited technician. That way you’re guaranteed to have years of trouble-free towing.