I have done a search and found a couple other threads with a similar situation but any remedy listed did not work for me.

As stated in title, Fuse #9 blows within seconds of turning ignition switch to the ON position. Strange thing is, it has been somewhat intermittent. Fuse blew a couple weeks ago. Replaced it and drove for a week and then it blew again. Replaced it and it lasted about maybe a day. Now, every time the key is turned to ON the fuse blows.

Here are some things I have tried in hopes of isolating the source of the problem:

Removed POS lead from battery to starter - blows
Removed yellow wire from ignition to starter - blows
BTW... reverse light wires are disconnected and taped off.
Removed all brake/tail/backup bulbs - blows
Checked for a short between Fuse 8&9 on the fuse panel - no short

Could it be the ignition switch?

The car still starts and runs fine except the following items do not work:

fuel gauge
tach
turn signals
brake lights
alt & oil pressure lights do not come on (when fuse is blown)

Wipers and fresh air fan work.

And, in case it matters... '74 2.0 D-jet

Thanks!

Check the brake light switch under the pedal board. The hot lead can come loose and arc/short to ground, blowing the fuse.

I had something similar and it was a bad bulb in the instruments.

Wow. That fuse powers a lot of stuff. I agree with Mike, the brake light switch is a good place to start, and can isolate a few things.

One of my tricks to avoid blowing fuse after fuse, is to wire a sealed beam headlight in place of the fuse. There is enough load to keep the circuit live without damage, and when the short is gone, the light goes out. Very helpful when moving harnesses around looking for intermittent shorts.

Have you had the rear bumper off lately? Even if you haven't check the leads for the plate lights. Specificly where they pass thru rear panel.

Just gonna suggest the license plate lights! I got the leads reversed on one of them once, and couldn't figure out why the fuse kept popping...

--DD

Another trick:

use a test light in place of the fuse. It will light up while the problem is shorted to ground and go out as soon as you clear the problem.

Just connect the test light to each side of the fuse holder.

Thanks for all the responses. I like the idea of hooking up a test light.

My rear plate light is not connected - wires are taped.
Will check the brake light switch this evening.
I swapped out the ignition switch and relay board - no difference.
I noticed on the wires to the ignition switch that two wires - one black, one red - going to the same connection have an ever-so-slight melted look to the black casing. Going to try to trace that.

I hate electrical issues

I'd check that tape just to be sure.

Not sure if it's on the same fuse, but the heater light on the floor near the shifter can shorten out easy. Is your heater lever in the UP position?

Are the plate wires taped back all the way THRU the hole? If they are chaffing on the hole with no grommet, that might be the problem.

I had a cigarette lighter outlet on my last 914 that was internally shorted that caused some problems.

Heater lever is in the OFF position. I thought of that, also, when the lever was in the ON position. Especially since it is not hooked to anything and never has worked since I've had the car.

Plate wires are inside the trunk. Haven't been hooked up since I've had the car.

Cigarette lighter... will check that along with about a million other possibilities

My fuse 9 has:
Double red/white stripe wire that goes to Hazard flasher switch, fuel gauge and tach

Double black wire that goes to seat belt relay and 15 on the ignition switch

I think the coil wire comes off 9 too?

Unfortutately, I am not going to have much time to troubleshoot this over the next few days. When I do figure this all out, I will post here.

In my research, I did find that Fuse 9 controls:

Alt charge indicator lamp
Low fuel warning lamp
Fuel gauge
Oil pressure indicator lamp
Tachometer
L/R rear tail lights
L/R backup lights
Oil temp gauge
Volt gauge
Clock

Thanks for the suggestions.

Finally got some time to take a good look at wiring and... found it!
The tach wire from the relay board to the interior had bare wire poking through one point
While driving, this wire would move around and at some point ground out, thus blowing the fuse and causing the problem at random times.
This time, since I was not driving the car, the wire remained grounded
So after chasing wires that lead to no results, the culprit was found, taped up, and my 914 will be driven this weekend

Cool! Thanks for posting the fix.

YES! Thanks for the closure!

Sorry but I dont believe that a shorted tach wire should blow a fuse.
The points ground that wire for every spark so it shouldnt pull any more current than the points being closed.
It could cause the engine to lose spark & run like crap or stop entirely though.

You are talking about the purple Black wire (pin 7 from front of the relay board, pin 5 on the engine harness side)?

Yep, that's the one. Maybe it wasn't that
All I know is the car is running fine and no fuses are being blown.