Lighting & Instruments

Lighting positions are very important. The light emitting surfaces of the headlights have to be a minimum of 500mm from the ground. All lights except fog and reverse need to be within 400mm of the edge of the wings. Rear lights need to be a minimum of 350mm from the ground. The fog light needs to be on the offside or centre line, and the reverse light on the nearside, or centre line and they have to be a minimum of 250mm from the ground. The fog light must be e marked and have a B or an F marking and be a minimum of 100mm from the stop/tail light. Ensure the fog light is 90 degrees to the ground, if it has arrows on the lens, ensure they point the right way.

Front indicators need to be seen from 20 degrees (if below 750mm) inwards. Side repeaters need to be seen at 5 degrees from the side of the car from 3m behind.

In theory, the wiring is an easy task, it all worked before you removed it from the MX5 so there is no reason for faults to occur now. Just plug it all back in according to the labels you attached to the loom, and make sure you have a good earth on all the points above. Obviously, you do not need wipers/heater/interior lights etc. so there will be plenty of redundant plugs, just don’t be too hasty in cutting them off as you may find you have created an IVA fail point should, for instance, the backlighting to your instrument cluster fail to illuminate. Some of these have a dimmer module that shares an earth path with other apparatus that you may be tempted to cut, but replacing the ground wire with a new one to the chassis fixes things!

A 10mm hole will need drilling in the side of the front lamp to mount the front indicator on the side as shown below. For IVA the headlight will need rotating in the rim to give a flat beam. If you mount them so that the dipped beam is not level with the road then they may fail but you are not required to have a kicked beam as seen on most cars. You may find the bulbs need replacing to ensure you have a flat beam that is defined.

EARTH POINTS. Very important.

• One from Battery to chassis.
• One to alloy beam near diff.
• One to alloy beam near the front.
• One strap from the engine to chassis above the exhaust manifold.
• One multiple earth at pedals.
• One above the exhaust on the front bulkhead (near engine earth strap).
• One at the petrol tank for rear lights/pump.

For a Mk1/NA donor the MX5 hazard switch also controls the headlamp motors which you no longer have so it is worth considering using a single pole one way switch with a hazard symbol on it. It does not need to light up as both tell tales flash when hazards are on. Just join the orange wire to the black via a switch for the hazards and leave the other wires with no connection. Remove headlamp motor fuses. For a Mk2/NB donor the above use of a simple latching switch with hazard symbol to ground the orange wire is still a neat way to go.

Number Plate Lights The number plate lights from the MX5 can be retained and re-used. A better option is to use the new LED number plate bolts, very neat bolts with lights built in, find them online.

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The rear wings have a “kick” to enable mounting of the rear LED lights. This unit contains the stop/tail light, rear indicator and reflector. You may need to sand the bottom edge of the light unit to get it to sit flush. The fog and reverse lights will need mounting separately paying attention to the IVA requirements, the fog light needs to be on the offside, and the reverse light on the nearside, and has to be a minimum of 250mm from the ground. Fog needs to be a minimum of 100mm from the stop/tail light. The fog light must be e marked and have an F or a B mark. It must be vertical.

Using projector headlights of Venom type gets complicated as they have single filament bulbs and therefore require wiring modifications to keep mains on when the internal shutter switches to dip.

When connecting the MX5 loom to your new lights the following will help you identify the colours.

You can mount the MX5 instrument cluster on an alloy bracket bolted to the column mount plate. You will have offcuts from the floor. You could make an alloy surround.

Or use the MEV GRP unit.

Note the fog and hazard switches neatly mounted in the corners of the pod. The switches must illuminate when switched on unless there are tell-tale lamps for fog/hazard in the instrument cluster. The fog light switching has an interesting IVA requirement: it must only operate when the main lights are on, and when the main lights are turned off it must turn off too and NOT turn back on again when the main lights are next turned on. MX5s do 'interesting' things with switches and wiring depending on model and equipment to make this happen. The required functionality can be achieved using a 'flip-flop' latching relay board as available on a well known auction site, and a momentary push-button switch marked as a rear fog light.

This works for the above version of the MX5, it might work on earlier models as well. Simply replace the bent metal wire which is the shunt resistor (at the back of the picture behind the 2 relays - has a resister sign under it) with a 10 Ohm resistor. Lights will then flash at the correct rate for IVA test.

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