19 September 2022
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A cruise control will make those long Motorway jaunts a little more enjoyable
: credit: © Trevor Cuthbert
Cruise control on your later Defender Td5 for under £20 is a must-do job. Trevor Cuthbert shows you how.
Need to know
Time: Around five hours.
Cost: £92.64.
Difficulty: 3 out of 5 stars
Models: Defender Td5 90, 110, 130.
Tools needed: Wire cutters, wire strippers, crimping tool, screwdrivers, 22 mm socket wrench.
Parts used: Cruise control parts as itemised below, £15.40; Td5 engine ECU connector gold-tipped terminals and wire seals (pack of five), eBay, £3.50; waterproof stainless steel push button momentary push-on switch (pack of 2), eBay, £3.95; rocker switch 12 V 20 A, on/off LED illuminated, eBay, £1.95; 2 m length of 7 core trailer cable, motor factors, £4; selection of electrical terminals and connectors, £2; optional new instrument cowls via BLRC: instrument cowl (plastic), Britpart MTC2808, £62.50; alternatively, instrument cowl (mild steel), Brooks Engineering, £37.
Work safely:
• Wear eye protection when drilling.
• Take care when cutting or stripping wiring.
Contact: BLRC, Tel: 028 9751 1763 blrcvehiclespecialist.co.uk
When researching this job on my Defender, a friend asked, “why would I want cruise control in a utility Land Rover?” Cruise control was considered an optional extra in luxury cars when it first came to my attention many years ago, but these days, while not a necessity by any means, it is a very useful feature for modern motoring. It also has certain safety benefits.
Cruise control not only makes long motorway journeys run smoothly, but can also be great protection for your driving licence. If used in conjunction with the posted speed limit, there is no risk of inadvertently drifting over the maximum and being caught for unintended speeding. Cruise control is also excellent for road sections controlled by average speed checks. Used in conjunction with the true speed reading from a sat-nav unit, one can progress at an optimum speed without risk of breaking the law.
The ECU in the Defender Td5 from model year 2002 onwards has the cruise control functionality already in place, but the wiring harness and switches were never offered by Land Rover as a factory option nor as an aftermarket option. However, the wiring is not complicated and the parts and materials are not costly – the whole job on my Defender cost less than £20.
Why fit cruise control to my Defender? Well it does see some extended motorway use on occasion, the dual carriageway between my house and yard frequently has mobile speed cameras on it, and it makes for more comfortable and relaxed driving on longer journeys.
As with any work on a Land Rover, it is best practice to disconnect the negative battery terminal before you begin.
Place the switches: The buttons and the switch for cruise control on the Defender will be on the instrument binnacle, conveniently located for hands on the steering wheel.
Expose the nut: There are a number of different centre covers on the Defender steering wheel. This one pops off quite easily, others need a screwdriver to remove them.
Leverage needed: The nut securing the steering wheel in place is loosened with a 22 mm socket wrench and can require quite a bit of force to crack it.
Avoid a fat lip: Until the steering wheel is loosened off the splines, leave the nut loosely in place, in case the wheel lets go suddenly and bashes you in the face.
Clear access: With the steering wheel out of the way, the instrument binnacle can be worked on without hindrance, and you can decide where to locate the push buttons.
Unplug the wires: Four screws hold the binnacle to the dash and, on the Td5 models, all connections between the instruments and the main wiring harness are electrical plugs.
Removed completely: The instrument panel can now be withdrawn from the Land Rover to be worked on at the bench, where locations for the switches will need to be drilled.
Stronger, cheaper: This instrument cowl has become brittle and broken and needs to be replaced with either another plastic one, or a tougher steel alternative – which actually costs less.
Parts retained: This lower bracket for the instrument cowl is reused on the new one, so is removed from the remains of the broken plastic unit.
Trailer electric cable: A multi-strand cable needs to be routed from the ECU in the compartment under the driver’s seat to the dashboard. This seven-strand cable is perfect for the job.
Choose the path: Grommets in the engine bay bulkhead provide options for routing the cable through to the interior. I cut this bud off the grommet, giving the perfectly-sized hole.
The right cut: With the cable end cut to a taper, it can be pushed through the grommet easily and fed inside to the dashboard. Ensure it’s tightly sealed against fumes.
Four of these are needed: When the cable is pulled through to the dashboard, the insulation is stripped off to provide tails long enough to work on for the connections (see colours later).
Repeat the exercise: The other end of the cable is routed down the bulkhead, under the floor, into the under-seat compartment where the ECU is located, via this grommet bud (arrowed).
More tails: The cable insulation is stripped back in preparation for the fitting of ECU connection terminals and seals to four of the seven cores.
Online specials: These gold-tipped ECU connection terminals are sold specifically for fitting a tacho or cruise control to Td5 Defenders, or indeed replacing damaged terminals.
Identifying connection points: There are four connections to make at the black plug from the ECU, at pins 10, 11, 15, 17, which should currently have no cables running from them.
Fine pliers or tweezers: At the rear of the ECU plug, these grey blanks can be pulled out individually to expose the holes into which the appropriate cable connectors can be fitted.
ECU connectors: When fitting Econoseal connectors, the green seal is fitted over the wire as shown before crimping the ECU connector terminals on, using the correct crimping tool. (Courtesy: mobilecentre.co.uk)
Three spare circuits: The four connectors are clicked into the black ECU plug , ensuring they are the correct way up, and the seals pushed firmly into position.
Green is plugged in as pin 11 and runs to the set/accelerate switch. Yellow is plugged in as pin 17 and runs to the resume/reset switch. Red and brown are a common positive ignition feed and are plugged in as pin 15 (red) and pin 10 (brown).
Obtain good quality switches: A pair of ‘momentary on’ push button switches are required, and an ‘on/off’ rocker switch, preferably illuminated. All are widely available online or from motor factors.
Tight spots: The push button switches will be mounted in fairly inaccessible positions in the binnacle, so they were pre-wired before fitting them in place.
Choose carefully: Select and drill positions to mount all three switches, ensuring that the back of the switch will not foul anything, and that the fixings can be tightened successfully.
Not out of place: The ‘momentary on’ switches are not intrusive at the top corners of the instrument binnacle, yet are easy to reach for operation of the cruise control.
Your own choice: I have chosen to position the ‘set/accelerate’ button to the left and the ‘resume/reset’ button to the right of the instrument binnacle.
Thinking ahead: The ‘on/off’ switch was mounted to the side so that the illumination is not shining directly at the driver at night, but can still be seen when in the ‘on’ position.
Temporary or not? Until I get used to using the cruise control system, I have added some rudimentary labels for each push button. These can be easily removed later.
Quick release: When wiring the switches, I chose to fit bullet connectors to allow easy removal of the instrument binnacle. Later, I soldered them after confirming the system worked okay.
The green wire is connected to a terminal on the set/accelerate switch, with the ignition feed attached to the other terminal. The yellow wire is connected to a terminal on the resume/reset switch, with the ignition feed attached to the other terminal.
Built back up: The instrument binnacle is refitted to the new steel instrument cowling, having plugged in all of the original plugs and the new bullet connectors.
Let there be light: Having switched the ignition on, the new switch is operated and the illumination indicates that the cruise control system is active and ready for use.
Installation complete: All that remains is to refit the steering wheel and go out for a test drive. I’m happy to report that the cruise control system is working superbly.
See more of our Technical 'How to' features here.
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