More Guts!

A not-so-dashing look behind the dash

In some respects pulling the dash out of a car is more intimidating than pulling the motor out. First, there are thousands of wires, connectors, and gadgets stuffed into this little plastic nook. Secondly, the Chilton book has minimalistic help, like: look for bolts, unscrew them, unhook wires, remove dash.
The picture above is after the dash was wrestled out and shows the locations of the car's climate control systems. Air starts on the right, either sucked in from outside or recirculated, and then flows to the left, through the A/C, and then the heater box. It was pretty gross when I disassembled this chain: imagine all of your air going through the same filter for ten years. In a house or office you can change the air filter, in the car it just piles up in the A/C or heater fins.

So why am I doing this? Well, New Hampshire has this strange occurence each year for a couple of days called Spring-Summer-Fall and then the rest of the year is Winter. Being a non-native I tend to require heat when it gets below forty or so.

Heater Core and enclosure

The way internal combustion engines provide heat is to pump radiator fluid through a smaller radiator behind the dash called a "Heater Core". It has fins through which all of the passenger compartment air flows. To keep you from roasting, the pipe going into the core has a little faucet or valve which is controlled by the car's temperature knob: as you move it into the red the valve opens, more hot fluid is cycled through the core, and any air being blown through gets hotter. The black enclosure on the right is where the core lives. Air comes in one side, through the core, and then through a magician's array of flaps and doors that determines if you get defrosted windows or toasty toes.

Nice thing about EVs is that you don't have all of these fluids to deal with. You also don't have all of this heat to deal with especially when you need it (around eighty percent of combustion energy is lost to heat). The solutions I've come across so far replace the core with a similar shaped core which is electrical. "That's gotta drain the system" you say. It's true that anything you add like this will reduce your range, but this is also true with a gas or diesel: but not as important, or evident. (try a long trip in the winter without any heat, radio, or headlights and then do the same trip with everything blasting and compare the gas mileage)

One of the interesting ideas I found was to use a household ceramic heater core. It runs off of 120vac, but it shouldn't mind if the 120 volts is DC. I have one in my garage that is rated at 1500 watts which pulls around 12amps, a far cry from the 60 to 200 amps that the EV uses to run the motor. You can also buy electric heater cores from EV suppliers which are probably more aptly suited for the task.

Another nice thing about electric heat in the car: the heat comes on instantly!

Oh, and while the dash is sitting on my garage floor I'm going to start measuring and designing where the meters should go. At the very least I'll be putting in an amp meter along with a general purpose electric meter that measures voltage, Kilowatt hours, and other handy readings.

One other thing. This make of Mazda has a black plastic box hidden deep in the bowels of the dash that plays little songs in lieu of warning you about open doors, low fuel, obnoxious friends, etc... Truly the automotive equivalent of elevator music.

For sale: 1985 Mazda 626 Sound Warning Control Unit


© Copyright 1995-2002 Jerry Halstead