You're doing it wrong.
The truck is getting persnickety about engaging the electrical system when I turn on the dash "Battery" switch.
It often takes several flips before the voltmeter registers and the starter switch will operate.
I can hear the relays in the PCB clicking on, yet the voltmeter indicates nothing and the truck won't start. I did give the PCB several good smacks with a hammer, but this had no effect which leads me in the direction of dirty grounds or perhaps a failing dash "Battery" switch. I have a Prestolite PCB, for what that's worth.
Sometimes, when I give the switch a few flips and the voltmeter does finally indicate, the voltmeter swings erratically across the red and yellow range before I ever touch the starter switch *with the truck not started, not running!* After a few seconds, it finally settles down into the high yellow, and I start the vehicle. This part seems pretty odd to me.
The "guts" of the battery switch seem a bit sloppy when I operate the switch, so this could be the problem. An easy way to troubleshoot, would be to remove the switch and simply jumper the leads and see if the electrical system comes on without fuss. I can also put a meter on the back of the switch and see if it still indicates open or an erratic closed condition when I turn the switch on.
In the "You're doing it wrong" category, I've noticed that there is definitely a technique to using the cold start system on the 809 series.
After turning on the glow plug and waiting for it to pre-heat, when you prime the fuel system with the hand pump, you must not delay in hitting the starter switch after priming the fuel system.
If I hit the starter immediately after priming, the engine starts on the second revolution, puts out very little smoke and doesn't miss at idle and warms up nicely. If you're slow with the starter switch, the "lit" fuel extinguishes and now you just have a cylinder full of cold fuel. The truck requires extensive cranking and smokes like Jackie Gleason, the engine has a slight miss and the truck shakes like an alcoholic on a dry-out until I get the engine temperature up. I'm not sure if this is specific to my old truck or if this is normal for the 809 series. In any case, once the engine warms up after 5-10 minutes, it's smooth and rock solid. When driving, the temperature is a perfect, 179F degrees.
My coolant heated personnel heater seems to be operating erratically. It was only blowing cold air yesterday, even with the engine up to operating temperature. I know the heater has its own thermostat, so I'll have to look into that.
I have one wiper motor operating erratically (plastic version) so I brought it inside for disassembly. It just needs cleaning and new O-rings. I'll see if I can source those today, after work.
If you open the supply valve too much, the wiper motor "stalls" and chatters, stuck on one side and when it does operate it has an asymmetric rhythm which seems to indicate that an O-ring on one side of the piston isn't sealing well.
These are all fun little projects that keep me occupied and thinking during the winter. Good times.