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Posted by: advman89 Feb 28 2022, 09:09 PM

I'm in the depths of a full dash replacement and I'm need to figure out a situation.

I have a couple things to address.

FUSE 11 (Hazard / Interior Light) has never worked-dead short immediately. I thought I remember someone saying that I need to look at the ground under the passenger seat and the passenger door switch as possible issues there. But I also have a some weirdness with the Hazard too...

There is a new square relay installed and some wires cut in from the factory hazard switcher. The turn signals are all working, but I need to get the hazards operational.


And on top of that, I discovered this red wire, long melted...will splice in a new wire, but thought the group might be able to point me in a direction.

I know I have a color wiring chart...off to the archives for it to start looking for things.

Posted by: 914sgofast2 Feb 28 2022, 09:13 PM

You have my sympathy. I am trying to sort out the turn signal and hazard light wiring on my 1970. The wiring diagrams in the Haynes book are virtually worthless. That said, a red wire is usually a “hot” wire from somewhere; it’s never a ground wire. All ground wires are brown.

Posted by: VaccaRabite Feb 28 2022, 09:28 PM

Big red wire is either going from the ignition switch to the starter motor, or the battery to the ignition switch. It carries a lot of current, and many of us have changed things around to use a ford solenoid to shunt the big current from the battery direct to the starter motor instead of routing it through the ignition switch.

Zach

Posted by: Costa05 Feb 28 2022, 10:48 PM

One thought, as one who is learning more an more all the time about the engineering behind these cars, (nerdly including Haynes book wiring diagrams), it appears at first glance to me that red wire may be the constant 12v input side to the ignition switch directly from battery terminal block (Haynes). Big yellow one would be the starter wire headed back to the starter through the 14 pin connector on your relay board in the engine bay. Others can correct me but this red wire in question
Is not fused from the factory which leaves it at risk of failure. One of the bad designs on these cars as others discovered.

Posted by: barnfind9141972 Mar 1 2022, 03:46 AM

What year is it? I have a 72-73 diagram that’s awesome and easy to read. I can snap pictures if it’s the right years

Posted by: Spoke Mar 1 2022, 04:48 AM

About the blue/white wire shorted to the brown wire on the flasher, likely the flasher installed does not drive the K/C2 pin as the OEM flasher did so the PO shorted the blue/white wire to brown wire basically shorting K/C2 to ground which is what I do for the EP26 LED-compatible flasher as shown below.

It could be too that the flasher installed only has 3 pins and doesn't have the K/C2 pin at all. If the Left and Right turnsignals work, then the flashers will work too as long as the flasher switch is functional.


For that burned red wire, at some point the wire tried to pretend to be a fuse but looks like it failed as a fuse and just melted the insulation. If you wanted to remove that wire from service, find out where it starts and ends and just add a new wire and leave the original wire in the loop as it would be nearly impossible to remove the old wire.

Posted by: Superhawk996 Mar 1 2022, 07:25 AM

I usually agree with @http://www.914world.com/bbs2/index.php?showuser=3031 100% but I would simply cut the cloth harness wrap, then remove the offending melted segment.

The reason is that when a wire melts this badly, it often melts adjacent wires in the harness which can lead to random shorts later on. At best some of the adjacent wires simply have melted but compromised insulation. I do get there is a theory that if there is no short there, leave well enough alone. That isn't the way I was trained as a electronics tech.

I'd fish out the melted red one (and any other adjacent wires that have melted insulation), and splice in a new section then re-wrap the harness. I think 914Rubber even sells cloth harness tape. If they don't it's widely available at other electrical supply houses.

I would also go back and get rid of the stupid quick splice connectors - those things are junk. Whenever I see those I immediately know the quality of the workmanship that has been done prior.

Finally, you need to find root cause of what caused the red wire to short in the 1st place before replacing the melted segment unless you wish to do the whole thing over again in the future should it decide to short again.

Posted by: advman89 Mar 1 2022, 09:13 AM

Thank you all for the replies.

The Car is a 1971 with a 2.0L

The starter was upgraded by the PO.

I'll start tracking it back and see where it goes, but I'm afraid of pulling the whole harness.

I'll see what I find and report back.

Posted by: advman89 Mar 1 2022, 11:33 PM

Gotcha. Check this out!

Opened the connector from the middle of the dash, pulled pin 1 Main Supply. Rest of wiring looks good.

Carefully unwrapped the original, coaxed the wire free...bit by bit back to the main above the fuse panel.

I inspected the wire and found no breaks, surprisingly.

Replacing the red wire proper and rewrapping.
(my Harness tape has disappeared! Dammit!!)

Question--should I put a fuse in that line? If so, what size?



Next up...hazards.

Thanks all.

Posted by: Superhawk996 Mar 2 2022, 06:57 AM

Nice job getting that out of there. Hopefully, you didn't find other wires adjacent to this one melted?

Before you power up your new repair, did you find root cause of what caused the melting?

Before you power it up again, you can use a Digital Multi Meter to very you don't have some sort of short still present.

I went back to OP and I'm not exactly sure what this red wire is. Is this the red feed to the flasher that Spoke posted (feed from fuse#8)or is this another circuit? Or, is it associated with Fuse #11 that you previously said has some sort of short? There a a couple of red feed wires direct from the battery to fuse #11 was it one of these?

Before the question of whether it can be fused, you would need to know what circuit it was and how much amperage it is expected to draw. Power from Battery? Power feed to ignition switch for starter solenoid? Power feed to buzzer?

Posted by: advman89 Mar 2 2022, 08:21 AM

I checked all the adjacent wires and there are no breaks.

The wire comes from the main supply near the fuse panel and is the supply for the plug near the middle of the dash (you can see a pic of that in the first posts).

I know the ignition was swapped at some point by the PO and nothing was secured well when I got it. I am speculating that there might have been a opening in the wire and it shorted under the dash.

I've looked everything else over and can't find any evidence of any further melting.

As for my Fuse 11 issue...haven't sorted that yet. This wire wasn't connected to the fuse panel.

Posted by: Superhawk996 Mar 2 2022, 08:48 AM

I'm a dope because I can't visualize your exact setup and what you mean by main supply. I've only owned 73's. and have to work via schematics. I'll go look at my harness to see if I can better understand which part that melted red wire is coming out of.

I checked all the adjacent wires and there are no breaks. -- Good job!

I am speculating that there might have been a opening in the wire and it shorted under the dash. For what it's worth, that wire didn't melt like that from some minor short like a small nick in the insulation. That was large short that drew lots of current, for a pretty significant length of time, and made lots of smoke. Would seem like the source would be sort of obvious but who knows what may have been done in the past and then ignored.

Keep posting your progress and what other symptoms you find.

Posted by: advman89 Mar 2 2022, 12:27 PM

Here are some photos...

PIN 12 (depending on diagram--some say Pin 1)- Supply. That connection goes to the ignition (I believe). That was replaced by the PO at some point in it's history.

The connection goes from there to the connection by the fuse panel. I had to cut the wire to get factory connector off (eyelet style)--the second bare wire there was also connected to the same wire, but didn't suffer the same melt.

I am very keen on burning electrical smells...and I've never once smelled anything "burning" in the car. Dad was in avionics and my other hobby is old audio equipment...so it's in my genes to suss out bad wiring, I guess!

Posted by: Superhawk996 Mar 2 2022, 02:01 PM

I'm out of my league based on the photos because I'm still not making heads of tails of it to get myself oriented to what circuit you're working on.

I don't think there are major changes between 72 wiring and 73 like I'm seeing in photos.

I just looked at my harness and the only place I have a 12 pin connector like that is out in the engine compartment that goes to/from the relay board.

Also on the left side of what I think is the fuse panel mount, I have nothing like what you have on there clipped or screwed to the fuse panel support bracket (thing with the screw). My fuse block left side bracket only has a ground stud. Yours has some sort of other arrangement back there with the screw & arrow is that what the red wire was attached to?

Posted by: advman89 Mar 2 2022, 03:55 PM

Mine is a 71. I don't know if there are a lot of difference>

The multi-pin plug supports the ignition now. Looks factory and I'm not seeing any splices. It "slots" into a place on the inside of the lower dash.


I can't find it here either....

Posted by: Superhawk996 Mar 2 2022, 04:02 PM

is this a 914-6?

Posted by: ejm Mar 2 2022, 05:44 PM

That power distribution junction block was only used thru '72. I've seen them get shorted out by aftermarket fuse boxes or metal cased relays that weren't secured in place.

Posted by: 914sgofast2 Mar 2 2022, 05:54 PM

I am going through a similar problem. The problem with the wiring diagrams is that they don't show the two sides of the 12 pin connectors and how the wires connect to them. The colors coming out of the ignition switch wiring and turn signal switch wiring on the early cars (1970-1971) are NOT the same on both ends of the 12-pin connector! Porsche used one set of colors on the female side wiring and another set of colors on the male side wiring of the connector. That must be why the posts were numbered on the 12-post connectors. It makes for very frustrating trouble-shooting.

Posted by: Costa05 Mar 2 2022, 05:59 PM

I have a 73 and dont have that screw post connection either. It looks like the PO installed a terminal block to make the spliced connection of two wires at that spot. Eyelet to eyelet. Likely trying to repair a problem, and the problem still exists evident of the melted wire. I would probably break out a continuity tester and voltmeter to confirm where it goes and what was its purpose. If by any chance it passes through the ignition switch, then knowing first hand that 914 ignition switches are super cheaply made, and high failure rate, I would put that as a potential shorting out location. A quick test would be seeing if you have continuity of the red wires to a ground location point. Battery disconnected. Test continuity in both key off, key on, and key start positions. If you discover continuity at all with test then you narrowed down your problem further. Best of luck.

Posted by: barefoot Mar 3 2022, 07:39 AM

I had to install a complete replacement harness in my 76 & decided to fuze everything as there were problems with the old harness.
Installed a 1 in 4 out fuze block near the battery for the 4 red wires coming off the battery. Fuzed with 2- 25 amp & 2- 10 amp fuzes. Now I sleep well

Posted by: Costa05 Mar 3 2022, 08:13 AM

One of the best things you can do for these cars. At least on the electrical side of upgrades.

Posted by: Superhawk996 Mar 3 2022, 08:48 AM

I hate to admit this since I generally think the engineers got most things right on the 914. However, @http://www.914world.com/bbs2/index.php?showuser=15673 's solution is probably warranted.

Standard practice on new cars is to put in a fusible link (or multiples) between the battery and the power distribution modules.

There are odd fuse choices on the 914 where I "believe" the fuses seem to large for the wire gauges involved but I have yet to do a deep dive analysis to portray this as "fact".

Definitely not like Lucas on Britt cars but could be better in my opinion.

Posted by: advman89 Mar 3 2022, 09:56 AM

It's there in my 1971.

So. Tonight. It comes out and I'll connect those two wires proper. Didn't feel right to me.

I do have the JWest Fuse Panel.

Posted by: advman89 Mar 3 2022, 05:42 PM

...and now I'll be adding in fuseblock near the battery.

Posted by: anderssj Mar 3 2022, 07:43 PM

That power distribution block is there on my '72... and it was both unfused and always "hot." I've since put a fuse box in for the 3-4 red wires at the battery.

We had a similar problem on my car back in 2004

We were out for a drive, hit a bump and smoke started coming out from under the dash. Fortunately it quit when I shut things off--and we were only about a mile from home.

The problem appeared to be caused by the front/ upper edge of the fuse panel/tray cutting through the insulation on one or more wires leading from/to the fuses. These wires looked like they had been resting on this relatively sharp edge since the car was built. I've since covered the tray edges with some plastic welting (like small weather-strip), so that should end it--but you may want to check on yours.

Hope this helps!

Posted by: advman89 Mar 4 2022, 08:50 AM

The ground block was removed last night, wires properly soldered together. Fuse block will get installed once the Great and Almighty Bezos delivers it.

Harness is re-tapped with the good stuff.

I've been keeping a good eye out for sharp edges.

Next up--Let's tackle that switcher and hazard wiring nightmare...


Thank you all!!

Posted by: advman89 Mar 14 2022, 12:19 PM

Fuse block is in place. I feel better. Thank you all!

I'm still trying to sort out the Fuse 11.
It's no longer shorting....but interior light still isn't working--no power.

Hazard switch_
Turn signals are working, but if you pull the hazards, the turn signals no longer work.

I have tried two different hazards with the same result.

Any thoughts?

Posted by: VaccaRabite Mar 16 2022, 12:00 PM

That's not a bug, that's a feature.

The hazard flashers and turn signals are the same bulbs. I don't think you can use both at the same time. I could be wrong, but I think the flashers take priority.

For the interior light check continuity from the fuse panel to the hot lead at the light. and then check continuity from the light back to ground. One of those wires likely has a break.

Zach

Posted by: ClayPerrine Mar 16 2022, 02:26 PM

When you pull the hazard flasher switch, all it is doing is turning on the turn signals on both sides at the same time. It completely bypasses the turn signal switch.

Posted by: johnorm Mar 23 2023, 11:43 AM

I'm doing the same thing as I rebuild my '73 loom. I fused the two 10 gauge red wires to the fuse box under the dash. Also added two 12 gauge wires for optional equipment like stereo and heated seats. Both looms I had showed heat damage to the these two key power wires and the yellow wire from ignition switch to the regulator board in the back. Also did the Ford solenoid conversion to reduce the load on the ignition switch.

Posted by: Geezer914 Mar 23 2023, 03:47 PM

Did the Ford solenoid for the starter and 4 fuses for the red wires coming off the battery. Don't need an electrical short torching the car! Fuses are cheap insurance.