Well, after a big post holidays push I've finished the heater controller to provide variable heat output. Remember that I have a very old BN2 heater which was designed for one heat output level; Foot-scorching hot but enough to heat an entire VW sedan at 40 below! I throttled mine back to luke-warm-ish and while it worked OK, the heat was sometimes anaemic or a bit too much, depending on the outside temperatures.
I wanted something just like Danny P and Jack Crosby: Start it up, turn a dash knob to the desired heat output and drive on. When it gets too hot, turn it down a bit. Too cold? Crank it up.
After a little component searching, a few Amazon orders, playing with component values to get it to run at the proper speeds needed by the heater (not go too rich or too lean on the fuel) and chasing a plastic box for friggin WEEKS, then fabbing in the basement, this is what came out. I used an extra dash knob for the control to match my dash. This little box is about 5" across and will be stuck to the underside of the (also black) radio with Velcro, making a little center console ahead of the shifter. The power button is on the right and there is a blue halo around the button that lights up when the unit is turned on. Pretty cool, huh?
These labels are for the car harness attaching to the box. They're on the top surface and can't be seen when Velcro'd under the radio.
"What's inside the Box?" A little pulse generator circuit board and a push-button switch. That little tab with the hole in it, lower left corner of the circuit board, is an electronic relay controlling the heater fuel pump.
Front view, power on, power light illuminated. I'm not yet totally sold on that cold-to-hot scale around the knob (it's just there for looks, right now). I can eliminate the white in the center, but with the red dot on the knob, I don't really think I need a scale and it looks cleaner without it. "Less is More", right? Maybe a top center label for "Micro-Scorch 3000" or something.
Now all I need is a couple of warmish days to rip out the old harness/control and install the new one and I'll have "Danny P. quality heat"!
I know that my old designers ( maybe @Michael Pickett, too ) would be peeling their eyebrows off the ceiling over the internal "cabling", but Hey.... It works! the runs aren't long enough to be dressed!
The birth of another great "Five Cent Racing" product!
If you have (or can find) a BN2 or BN4 heater in good shape, regardless of whether it has a working fuel system, I can spec out a fuel system for you AND tell you how to get it running using one of these controllers and a new fuel delivery system (new fuel pump and trash your old pump and regulator). Finding the heater and the proper control relays is really the hardest part. @Matt Berry this is aimed right at'cha, buddy (not that you need a lot of heat in north Florida).
Something to consider if you want better heat in your Speedster/Spyder/Microbus/Semi-Truck sleeper cab.