Our focus this week was on getting the heating system re-installed. Part of this involves wiring up the back-lighting for the heater controls. A couple of the bulbs are T5/286 bulbs that you can get LED equivalents for. We are upgrading all of it to LED and adding brightness controls for the instrument lighting.

The tombstone switches for the pop-up headlights and the hazard lights are illuminated with unusual bulbs that screw into holes on the underside.

These strange little bulbs are 12V and have a green tinted cover over them. These are being replaced by 3mm LEDs with in-built resistors as I'm not aware of any modern counterparts. I will be reusing the plastic part that screws into the hole.

There is also one of these bulbs in the heater switch module, which illuminates the air conditioning switch. You have to get the polarity correct with the LED replacements.

We tested the heater controls with the heater blower. Thid is one of the very few parts of the wiring loom that we left intact as we saw no need to touch it.

There are two wires on the heater control connector that are not used in our installation and we also want to use the air conditioning switch to control the PTC heater. This function isn't actually exposed via the connector, although testing showed it is available on the switch module itself. It is important that the PTC heater only comes on when the fan is in use and the logic to achieve this is actually already present.

We cut one of the unused wires and soldered it to the point where we get the required signal, so that it is now exposed via the connector. This will pull the negative side of the contactor that powers the PTC heater down to ground wheh the swithc is pressed but, only if the fan is also on.

We thought we had removed every single bolt on the MX-5e but, having bumped into the mirrors one more time, we realised they needed to come off. As is typical with a 30+ year-old car, one of the 6mm bolts was rusted badly. We put PlusGas on it and left it for a day but, this didn't help. We tried some heat and that didn't work either. An impact driver was likely to damage the door, so we ruled that out.

We already have new mirrors to go on the car and these will be resprayed to match the bodywork later, so we were not too concerned about damaging the mirrors.

Eventually we cut the head off the bolt and drilled though the middle of it to weaken it, using a 1mm drill bit, followed by a 3mm drill bit, then a left-hand 4.8mm drill bit. This left just enough metal to collapse and reveal the threads.

We ran a tap through the threads to clean them up. The paintwork underneath is not brilliant but, it is all being resprayed in the new year.

We now feel confident enough to take the first box of wires from the old wiring loom to be recycled.

The second installment of our MX-5e build is published in the MX-5 Owners CLub magazine this month (called Soft Top Hard Top). It is a real challenge to distill the huge amount of work down into a few thousand word article. Installment number 3 has already been drafted and the plan is to have the car on the road by the time part 4 is published.

And yes, I know they got Ethan's name wrong in the title.

Picked up an aluminium washer fluid tank from Doug at G19 Engineering today. It weighs 515g and frees up space in the engine bay by replacing the old tank, which sat on right of the engine bay bulkhead. This new one sits underneath the windscreen scuttle. It reuses the existing pump and rubber grommet. The main reason for doing this is to provide more space for the inverter in the engine bay.

Trial fitted the washer fluid tank today, to check the best route for the pump wiring. There is a convenient hole in the bulkhead for it and I fitted a rubber grommet for the cables to run through.