I guess eventually thru the process of elimination i will get this figured out, but in the past few days / week of driving the car every day i have had this fuse blow on me,
its happened with the fog relay removed, with the fan off with the fogs off, yet at some point during a 30 minute commute i have lost that fuse. when it goes, i loose the tach, the fuel sender gauge, lights in center console, fog light and fan function. not sure what else, i think the brake light is on this circuit too . I have the Egman blade fuse box upgrade, this was done 8 years ago.
i dont think its the fresh air fan circuit, but am suspecting the fog light relay plug or switch, but then again, i blew a fuse with that relay out, power i believe comes to the switch threw it to the light, not sure where its getting shorted, its not there but then suddenly bam. i have not had the issue or short if thats what it is stay long enough to blow the fuse right when i reinstall it, but has anyone else been thru trouble shooting this specific circuit and know everyting on it, because i know theres stuff connected to this circuit thats not listed in the Haynes or the tech tips book.

PHil

OK i reran my search and found this for a '74 from Jeff Bowlsby listing each fuse bank,

http://www.914world.com/bbs2/index.php?showtopic=293074

so what should be on this circuit is this:

Alternator Charge indicator lamp
Low fuel warning lamp
fuel gauge
Oil pressure indicator lamp
Tachometer
rear stop lamps
back up lamps
oil temp gauge
voltmeter gauge
clock

what is not on it is the fresh air blower motor, that should be on #8, so maybe this is hooked up incorrectly , i know the light for the blower controls are correctly going thru the #8 but the motor is not, but i could be just getting an intermittant short thru the brake /stop lamps, hard to tell , it only happens when driving.

also i notice jeff has the S10 as having the parking lam inicator and fog light and horns but they run thru the #9 fuse on my board, there are only 12 fuses, and he shows S13
edit- just saw the #13 is on back panel, —

Check the "defrost" light on the bottom panel of the center console, it can short out and blow that fuse.

Unscrew it and check the back. There's very little room for error. When i still had the console, i added extra insulation to prevent shorts.

@SirAndy
sorry its not clicking, the "defrost" light in bottom panel? i am not sure i know what you are referring to. in my center console i have 4 gauges, oil temp, volt meter, CHT, AF.
on floor is the heater blower lever, no defrost switch or light. but maybe that wire is under there causing an issue?

Phil

this I think

Yupp, that one ...

Check the grommet/wire on the license plate lights too.

On my car, I would lose the tach to a popped fuse when I went over a sufficiently-hard bump.

One of the screws that holds the fuse block onto the fuse panel was MIA, and a bump would shake it just enough so that one of the plugs on that circuit would touch the edge of the fuse panel. But the block would move back up into place, probably due to the wires having taken a "set".

Took me a very long time to properly diagnose that. I finally put a new screw in and I think I also put a split piece of hose along the inner edge of the panel? No more problems with the fuse popping.

--DD

Dave, it certainly could be something like that, i took the panel down tonight to check those connections, look for loose wires etc, and found the defrost fan was wired to the 7.5amp circuit next to it rather than the 20 amp circuit it should be on, then made sure nothing was loose or in the wrong place. still could be something else on that circuit like Andy was pointing out, so if it happens again, i will be looking colors at that center console gauge wiring. i don’t have defrost doe rear widow hooked up , i hope i don’t have to pull the console.
still have to recheck the license plate lights , back up and brake light connections too- could be anywhere.

The rear window defrost has absolutely nothing to do with the light on the bottom of the center console. Just making sure there is no confusion here.
That light is always on when the lights are on to let you know that there is a big red lever for the fan right next to it.

The backside of that light is dangerously close to the chassis and if i recall correctly at least one of the mounting screws is within a mm of the tiny hot lead.

more investigation today with some trial and error lead me to finding that the short is related to the signal ! tested each corner and found the culprit is the right front turn signal bucket, it seems that connection is shorting OR somewhere from the column to the light bulb socket- that socket has the euro conversion light installed , i am thinking that has shorted out inside the housing .

in the mean time and while checking all the wires and fuses i found the fog light wire was on the #9, not #10, so that has been corrected . - it appears that the center console was not the issue.

now i have to decide if i should just get a new turn signal bucket assembly or attempt to fix old one