shocking!

[froggy]

While reading a thread DD posted a reference to fuse layout I checked and found that I keep blowing fuse 8. But I also noticed that I have a 16 amp fuse in the slot. Should it be a 16 or a 25 amp? Will replacing my 16 amp fuse a 25 amp fuse will fix my problem?

[ruddyboys]

Froggy, here is the link to the fuse diagrams:
http://www.pelicanparts.com/914/technical_specs/914_electrical_fuses.htm
On the 70 to 73 fuse 8 was a 25 amp, on 74 and latter the fuse was changed to 16.

[Toast]

If one particular fuse keeps blowing, it means that it does not have enough amps. Change it to a higher ampage.

[Dave at Pelican Parts]

It could also mean that something in that circuit is shorted to ground. In which case, putting a higher-rated fuse in could result in frying the wiring or some other component....

--DD

[914GT]

That's why they call him Toast! Just kidding Toast ...

[Dave at Pelican Parts]

"Him"??? Dude, you seriously need your eyes examined.... Toast is female. Very emphatically so, if her pictures (or her icon, woo woo!!) are any indication!

--DD

[914GT]

Yeah, but also from California and you can't really always tell by ... oops I better not go there. So there are actually female 914ers who hang out here??

[froggy]

I never had a problem before; untill I wanted to get the thing on the road. Then out of no where comes all these problems.
I'll keep looking for a grounded wire and think about this fuse thing some more. thanks

[914GT]

Froggy - you do have a digital multimeter don't you? They're cheap. At least get a continuity checker to try to shoot down these problems, otherwise you're just shotgunning the problem or trying to find it by trial and error. Also familiarize yourself with the wiring diagrams. Keep a copy in the bathroom for reading material

[froggy]

I do have a digital multimeter I just don't know how to use it. I know how to check for Voltage. But when it comes to checking for resistance I don't really know what I'm looking for. If I have a short on a wire should it read 2.38 or should it go back to 0. last night I used my multimeter to check for resistance. I closed the hazard switch and checked the black and white (L) wires for resistance... 0 when I pulled the switch the meter read 2.38 or somthing under 3. I'm at a stand still here.

[914GT]

Maybe I can give you a couple of hints here to help you out. When checking for short circuits you can put the meter into a continuity check mode where it just beeps when the leads are held together. Any resistance less than a couple ohms or so will beep. But make sure no voltage is present on the circuit when measuring resistance or continuity or you will get screwy results. Disconnect the battery if you have to.

Did you change fuse 8 to a 25 amp? If it is supposed to be 25 and you only have 16 then that may be all it is. I looked at the diagram for a '71 model and there's a lot of stuff on that fuse, more than fuse 8 on my '74. If you're blowing a 25 than you need to leave out the fuse and work down from there. If still a problem with the left turn signal, then leave the blinker and lights off and pull the left side bulbs and check continuity between the center bulb contacts to ground (chassis). It should be an open circuit. If it beeps or measure a few ohms then there's a short to ground in the wires somewhere, or short in the bulb socket, or back at the switch. It's all a matter of isolating the various sections of the circuit to try to zero-in on the problem. Hope you find it.

[Dave at Pelican Parts]

It might be a good idea to check into an electronic circuits class (basic level) at your local community college or vo-tech school.

One way to view the system is: Electricity is a fluid. It flows from the battery (+) terminal, through "stuff", to the battery (-) terminal. There must be some kind of path from + to - in order for the electricity to flow; if there is an interruption in the path with no way around it (e.g., you disconnect the battery ground strap) then there will be no flow. Most circuits in our car ground to the metal body of the car, which provides the path for the electricity to get back to the (-) terminal of the battery, by way of the battery ground strap.

Voltage is the "pressure" of the fluid. Current is the "amount of flow" of the fluid. Resistance is the resistance of something to this fluid flowing through it.

You can measure current flowing through a point in a circuit. You break the circuit at that point, set your meter to "amps" (and possibly move the plugs to the correct ones for amps!!), hook one lead to the one end of the break and the other lead to the other end of the break. The meter will then tell you how much current is flowing through it.

You measure the voltage across something, be it a specific component or a bunch of wire. You usually do not break the circuit. Set up the meter for measuring Volts, make sure the leads are plugged into the correct parts of the meter. Then hook one lead to one end of whatever you are measuring across, then hook the other lead to the other end. Often we are checking the voltage across "everything having to do with that circuit". In that case, we are measuring from a specific point to ground, or to the chassis. That's what we generally mean when we say "look for +12V there". But you can measure the voltage drop across a length of wire, or across a light bulb, or across something else as well.

You measure the resistance through some specific piece of circuitry. Resistance measurements get messed up if there is any electricity flowing through the circuitry at the time, so you want to turn off or disconnect the power from whatever it is you are measuring. The electricity will also take the easiest path to get back to the battery, so if there is more than one way for it to go around what you are measuring, you probably want to unplug it. You set the meter to "ohms", and make sure the leads are plugged into the correct ports on the meter. Then hook one lead to the one end of the circuit you are measuring, and the other lead to the other end.


Fuses are there to protect the wiring of the car, and the electrical parts of the car. When too much current flows through a fuse, it will fail ("blow") and it will no longer let any current flow through it. If a short happens and more and more current keeps flowing through a circuit, the wires can overheat and melt. Or even catch on fire. Or sometimes, if the short is "downstream" of some electrical part, all the current could flow through that part and it could overheat and melt or burn up.

In general, the fuses are sized as they are for very good reasons. Don't put bigger ones in "just because".

I hope this general advice helps somewhat in your understanding of the electrical system of the car. Sit down with the wiring diagram some time and trace out how the electricity flows through some of the circuits. That can also help your understanding. And don't be afraid to ask questions.

--DD

[Toast]

Originally posted by Dave at Pelican Parts
It could also mean that something in that circuit is shorted to ground. In which case, putting a higher-rated fuse in could result in frying the wiring or some other component....
--DD

Thats true too. Forgot about that.
Last time I checked I was still female! And Yes 914GT, there are cool teener chicks that hang out here. (Yea, I play the drums too!) Look for the "Baja II" threads......there are pics on those threads that I am included in.

Toast
aka: The Wench Wrench Twister
Toast Quote: "If you see a car on the side of the road with a firey red-head wrenching away, you will know what vehicle is Toast's."

[Toast]

Wiring Sucks!! Hopefully your wiring system will not have been butchered and have different color wires on the same string of wire! Now That is a nightmare to figure out.......no wiring diagram can help you there!
Personal electrial disaster experiences...........

[914GT]

Toast - my apologies for being clueless. Good to know there are members of the opposite sex hanging out here. At least not all just a bunch of 914 male nerds (not to imply that you're a female nerd of course). I share your frustration with butchered wiring systems. My car had been hacked by the POs with cobbled up alarm systems and radio hookups. Then had to straighten out the mess where relays were bypassed and wires going every which way in the engine compartment. I'm amazed that the damn thing ran long enough to get me across town (actually it died right when pulling into the driveway - I had to push it the last 50 feet). I'm an EE and this car's wiring almost drove me to the limit sometimes. I can understand the frustration everyone else has.

[froggy]

Thanks for all the great info. I will continue on my quest.

[D7N7MASTER]

WhoooHooo, Dave... great explanation of current flow. 10 years ago I heard the same lecture in a basic electricity class. Your right on when stating that electricity takes the easiest path. But lets just back up a step. Not one of our 914's is less than 26 yrs. old. Due to environmental conditions over that many years, the heat the engine compartment experiences, and 1970's technology, our "existing" wiring has become ahhhh - comprimised @ best. Trouble shooting old, cracked, corroded wiring, and wiring terminals will drive you batty. In my short 4 years of teener ownership, wiring is the ONLY reason I have EVER had to push my car to the side of the road. I'm an ex jet mechanic - having performed trouble shooting techniques on thousands of aircraft over the years. Thanks to this board & a BIG reality pill - I have come to terms with NOT applying band-aids to relieve / "extend" a wiring harness that simply is in need of replacement. Want your multimeter to lead you to "root cause"? Replace the wiring FIRST with new. The expense of the wiring will be minimal in comparison to the frustration you will experience trying to troubleshoot a wiring harness that may short to ground occasionally. Years ago our 914 was runnin' fine coming back from a Big Bear run when all at once - on the freeway at 65mph+ the tach would jump from stop to stop and in concert with the tach, the engine would die, light, die, light, over & over. She's SOOO sweet she got us home. I shut her off to open the garage, but she would not start again. Quinkiedink? No. She loves us 'cause she's family. I have no other explanation. Tore into it the next day and guess what? Fuel Injection wiring had missing insulation. Right next to my electrical tape repair!!! Moral of story? If you love your car like we love ours, replace - don't repair wiring problems. Once it's all good you can drive anywhere at any time & smile like a Mo Fo.
Toast: U ROCK!!! My wife gives me grief when I ask her to help bleed the brakes!!! let alone grab a wrench. She's a redhead so I'll exclude genetics...hehehe - ROCK ON!!! If you ever see a SWEET yellow '73 914 in Buena Park, give me a shout. I'll buy you a beer.

[red-beard]

My favorite lesson from my Electronics class in High School:

Bad Boys Rape Our Young Girls But Violet Goes Willingly

James

[914GT]

Who besides me knows what the hell you're talking about?

[red-beard]

Yeah, I bet it wouldn't pass the PC tests these days.