01-23-2015, 04:19 PM | #1 |
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928 Indicator Lights & Hazard Switch Wire Melted
Hey guys I am new to the forum. I have owed several porsche's in my life but at the present time I owe a 1986 928s and I am hoping you guys can help me with the following issue I am having.
When I purchased the car she had been sitting for a while with only 3 owners (me being the 3rd) and 54K in milesshe is in very good condition but has many of the gremilns that come up on the 928's that have been left sitting. I have fixed all of them but one and the issue is as follows: I pulled the CE panel out to do a cleaning as normal and here is what I found: (For reference I also have the POD completely removed from the car so I have direct access to all switch bases) 1. I took notice that the "B" plug has a wire at pin "15" that got so hot from the back of the plug heading into the wiring harness that it melted the rubber covering right off that wire all the way to the harness up under the dash. 2. Also I noticed that on the back of the CE Panel where the "B" Plug would attach into the CE Panel there is a jumper wire from pin "15" to Pin "14" of the "B" Plug that is also had it's rubber partially melted off it. 3. The wire is black and is a power supply when the ignition key is in position 2 and start. The wire originally starts it's life at the ignition switch Terminal 15, goes to the CE Panel - "B" Plug at Pin "12" and jumps from there to Pin's "13", "14" & "15". 4. From Pin "15" it exits the back of the plug, goes up into the harness under the dash and according to the schematic I have it comes straight to Terminal 15 of the Hazard Switch. See this link which is Page 4 and you go to grid G5: http://www.manualslib.com/manual/392...?page=4#manual 5. I have checked the continuity of the wire between the ignition switch and the "B" Plug Pin "12" and all is good. I have checked the continuity of the jumper wires from the "B" Plug Pin "12" all the way to Pin "15" of the "B" Plug and all is good with the wire. 6. I checked the continuity of the wire in question from the "B" Plug Pin "15" to the bare copper where it disappears into the harness under the dash and I have continuity but when I check it from Pin "15" back to the Hazard Switch Base at Terminal 15 I have no continuity which seems to me that the wire in question must have burned through and severed itself up insde the harness. Would this seem correct to you folks based on the attached schematic? 7. There are NO burned or melted wires at the Hazard Switch Base. FOR REFERENCE: These are the rest of the items pulling power on that line from Terminal 15 of the ignition switch to the "B" Plug Pin "12" "B" Plug Pin # 12 feeds power to Pins "13", "14" & "15" but it also feeds the 7.5A fuse for the AC which then travels back out of the CE PANEL via "G" Plug. "B" Plug Pin # 13 goes to the back window heater switch. "B" Plug Pin # 14 goes to the kick down switch. This whole issues is centered around the Hazard and Individual blinkers for all 4 corners of the car. Now here is the problem. The Hazards work but the individual blinkers do not. If you look at the schematic page noted above you will see that when you push the Hazard Switch in to make the hazards works you get power from Terminal 30 which is direct battery power. When the switch is open which is the default you get turn signal power from Terminal 15 via the "B" Plug Pin "15". I believe the fix is to replace the burned wire from the "B" Plug at the CE Panel to the back of the hazard switch and then my blinkers should work. What do you folks think? Also what the heck could have caused this to happen? Nothing else is at all messed up in the car. The car has not been hacked in any way it is all original. No water from what I can tell. I find it very odd so any help you guys can offer would be greatly appreciated. Thx in advance for all your help, A |
01-24-2015, 01:12 AM | #2 |
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That I just can't follow those wiring diagrams. I see the B plug and the jumper between 14 and 15 that you mention but not where B15 runs to on G5.
There are a few unfused wiring connections in the car and I've seen fried wires. FWIW... I don't think it's the flasher circuit. That relay (XIII) routes to B24.
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1980 928S Euro x2 1987 944 N/A |
01-24-2015, 08:29 AM | #3 |
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Thx so much for trying to help.
On the 2nd page you posted at Pin "15" of the "B" Plug you see the G5 notation. That means grid G5. If you go to the 1st page you posted and cross grid G at grid 5 you end up at the Hazard Switch. |
01-24-2015, 08:33 AM | #4 |
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In grid G5 B15 is noted at the edge of the CE Panel line. Than it travels to Terminal 15 of the Hazard Switch.
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01-24-2015, 08:43 AM | #5 |
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The fog lamps are working fine, all the wires associated with them are intact and B24 is not in the circuit.
I am thinking about cutting all of the tape off of the harness back until I find the melted through wire. |
01-24-2015, 11:12 AM | #6 |
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I'll take a better look at it later on. Porsche used different styles of diagrams for different years and the years wiring varies. These are the worst, in my opinion, and it doesn't help that the scans are fuzzy. The ones I've got are bigger than what the forum would let me upload.
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01-24-2015, 12:43 PM | #7 |
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Agreed and the PDF I have of the full 86 electric is 2.6mb so I could not up load either.
One thing I will say is that I checked my 86 car against the 86 schematic and everywhere I checked it matched 100% so just lucky on that one so far. |
01-25-2015, 09:49 AM | #8 |
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No one else has an opinion???
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01-25-2015, 11:03 PM | #9 |
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Looking it over, I think you've got it figured out. The older diagrams show the same circuit better with 15 being the switched power and 30 being unswitched power.
When you're re-wiring the CE panel, scavenge an unused fuse (or two) and add it to the circuit. I've had some hot wires fry out as well. It's amazing that they route non-fused hot wires out of the panel. The lights all have fuses but the wiring to the hazard is unprotected. You may find that there's a short between the panel and the hazard switch, or in the switch, and it's an intermittent fault.
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1980 928S Euro x2 1987 944 N/A |
01-29-2015, 01:53 PM | #10 |
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this forum is not too active on he technical side any more. The best place is rennlist, 928 forum. If it wasn't for Glen, I'm not sure that the lights would still be on here
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Ed 85 5spd 928 (guards red overtan) 05 6 spd 997 (slate gray over terra cotta) 928 Owners Club member |
01-30-2015, 07:00 PM | #11 |
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I suppose... It started off well. I'm still hoping we can have a forum that's smaller than Rennlist with good technical content and less arguing and barroom shouting stuff.
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1980 928S Euro x2 1987 944 N/A |
01-31-2015, 01:52 AM | #12 |
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still here, too
Hey, this is still the best as far as I 'm concerned..... there has been some evolution for sure.... but going back to the days of Walt, Kibort, Eifort, Nichols, Harkin, Ruiz, Kempf, the crazy guy from Florida, and who was that guy.... Geno or what Gene????
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02-04-2015, 10:06 AM | #13 | |
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Quote:
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1980 928S Euro x2 1987 944 N/A |
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02-21-2015, 09:47 AM | #14 |
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I'm around too but have been quiet lately.
Step one is uncover the burned wire into the harness until you find where it stops. There are likely other wires bundled with it that had the insulation melted off and they will cause problems in the future. Other that that, adding a fuse is not a bad idea. There are unused ones on the CE panel. I like this forum better because there is a lot less noise. Just people who want to really help others. |
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