Mazda MX5 Conversion Blog


30 September 2007: Interior removal - what a mess!

This blog entry actually represents many days of occasional tinkering with the interior removal. I'm finding it easiest to just put in half an hour per day than finding large blocks of time to work on it!

There are quite a few things which need modification inside the cabin when converting a vehicle to electric, the main items are rewiring the ignition and instrumentation, removing the ECU and getting to the heater core so it can be replaced with an electric heater. You don't necessarily have to remove the ECU but it's just dead weight to leave it in there. And you can actually use an electric fluid heater which works with the existing heater core, but they are quite expensive and the electric heater seemed to me like a more "electric" solution.

The first things to come out/off were the seats and steering wheel. If you're doing any significant work on a car's interior, removing the seats sure makes it easier to work in there. Following this came an assortment of panels including the centre console.

The roll bar was getting in the way so I took it off and unbolted the seatbelts. While working on the back section I also removed the carpet and a metal panel, finding an access hole to the top of the fuel tank (3rd picture). Unfortunately I can't get the tank out the top though, I'll still have to drop the rear suspension out for that. Such an difficult car to get the tank out of..

Anyway, back to working on the dash, the instrument cluster came out next. I unfortunately broke a couple of clips off plastic hood while removing it (the old plastic had become rather brittle), might have to source a replacement when it all goes back together.

The bulk of the dash comes out as a whole module. It's held to the car body by about half a dozen bolts (most of them behind little plastic covers - easy enough to find). There are also three pushrod cables you have to unclip between the heating instrumentation and "back end", and half a dozen or so header plugs for the wiring. The whole dash weighs about 15kg so it's not heavy but is pretty awkward to get out by yourself!

With this removed I had access to the ventilation system (see 6th picture below, on the left). The box with the heater core that needs replacing is furthest right (i.e in the middle of the car), but they're sort of coupled so it's easiest to get the whole system out in one go. Pictures 8 and 9 show the heater core itself - I'll have to mount an electric heater in it's place.

The last thing I've taken out so far was the Engine Control Unit (ECU). This is underneath a panel in the passenger footwell. You have to lift the carpet then unbolt the cover to get access to it (pictures 10 & 11).

I'll leave the interior stripped out until the drivetrain is fully installed, as it'll make it easier to work on things. At some point I'll have to have a strong coffee and unravel those huge wiring harnesses to work out which wires I can remove (e.g everything which used to go between the ECU and engine sensors).


(1) Seats, steering wheel and some of the panels removed

(2) More panels removed

(3) I was curious to know what was under the parcel shelf - access to the fuel tank

(4) Back to the dash - instrument cluster out

(5) The bulk of the dash comes off in one section

(6) With the dash removed, you get access to the ventillation system etc

(7) The three components of the ventillation system

(8) Location of the heater core

(9) Removal of the heater core from the access hole on one side

(10) The ECU is under the carpet in the passenger footwell

(11) It's that little grey box there, protected by the metal panel

(12) Intimidating wiring harnesses.. one for the To Do list

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--> Continue reading: Taking out the clutch, tidying the electrics and.. my motors are here!


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