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Posted by: vin man Feb 11 2017, 06:08 PM

Edit: Renamed the thread because what started out as one electrical problem has led to others and I'm hoping to capture all the information in this one thread.

Initial Problem:

When I turn on the 72, the red light on the dash (in the top part of the gauge on the left side of the dash) blinks and won't stop. I've made sure the e-brake is all the way off. I'm wondering where is the switch that controls this light?

I've read that when the brake master cylinder is replaced, there is a switch on the MC that needs to be reset. I used a MC from Rock Auto and there is not reset switch button. Only the electrical switch that activates the brake lights.

I have a brown wire that is connected to nothing in the area of the e-brake handle. I've tried grounding it but the light still blinks on the dash.

Any advice would be appreciated.


Click here for video of the blinking light: http://vid304.photobucket.com/albums/nn179/e065206/Our%20Cars/1972%20Porsche%20914/EF0FB0FB-6DA8-422A-8559-7458F3DDF30C.mp4

http://s304.photobucket.com/user/e065206/media/Our%20Cars/1972%20Porsche%20914/DE816563-9BD8-482C-9A7C-965C2D96DB84.jpg.html

Master cylinder:
http://s304.photobucket.com/user/e065206/media/Our%20Cars/1972%20Porsche%20914/1605E642-D557-43B6-B099-0190F9D6D351.jpg.html
http://s304.photobucket.com/user/e065206/media/Our%20Cars/1972%20Porsche%20914/F69859C7-92C0-497D-81BD-F1A189A436AC.jpg.html

Posted by: Spoke Feb 11 2017, 10:32 PM

The brake warning light will flash if the brown wire by the e-brake is grounded. Also if the switch on the MC is closed. Try disconnecting the wires on the MC switch and the e-brake wire is not grounded. This should cause the flashing light to stop.

Posted by: vin man Feb 11 2017, 10:43 PM

The wire is currently not connected to anything so not grounded. I will pull the wires off the switch on MC. If I do pull those wires and the light stops flashing, do I lose any other functionality by not having them connected to the switch on the MC?

Posted by: vin man Feb 11 2017, 10:45 PM

I've been doing some more research and did find a thread that had a picture in it and I spotted the switch. I circled it in this version of the photo:

http://s304.photobucket.com/user/e065206/media/Our%20Cars/1972%20Porsche%20914/brake%20light%20switch.png.html

Will also try disconnecting the switch on the MC.

Thanks to this thread for the help: http://www.914world.com/bbs2/index.php?showtopic=148100

Posted by: AlanB Feb 12 2017, 08:01 AM

Wow, talk about the right post at the right time. I just replaced my ignition lock and the big red light started blinking when I turned the car on. I was ready to start going through all the steering wheel connections when I saw this post. I'm a newbe and I never thought of the parking brake. THANK YOU for saving me some really frustrating time.

One maybe useful suggestion. The brown wire is pretty thin and could be easy to break. Mine's now under a thin strip of duct tape to make it more obvious and to give it some protection.

Posted by: vin man Feb 12 2017, 11:46 AM

I took the wires off the MC and the wire off the switch at the handbrake. The light still flashes on the dash.

Posted by: rgalla9146 Feb 12 2017, 12:23 PM

Find the wire at the hand brake switch and disconnect it.
Follow it out of the seat crossmember and wherever it goes to
be sure it is not making contact with anything that could ground it.

Posted by: vin man Feb 12 2017, 01:31 PM

OK, thanks. I've got family stuff do do today so no more working on the car till tomorrow night after work at the earliest. Will keep going on the electrical debugging at the shop asap!

FYI - I did pull the relay that was causing the flashing. While the red light did go off and stop blinking, the turn signals also stopped working. Apparently, they share a relay. I put the relay back as turn signals are important.

Posted by: Spoke Feb 12 2017, 01:58 PM

You can pull the bulb out to stop the flashing.

Posted by: vin man Feb 12 2017, 03:45 PM

will I still hear the clicking of relay?

Posted by: Spoke Feb 12 2017, 05:03 PM

The relay will stop flashing when the bulb is removed. See the turnsignal/brake warning schematic below. one of the wires from either the MC switch or the e-brake switch is shorting to chassis. Removing the bulb will break the circuit and the flasher relay will not operate.

This isn't a fix of course because somewhere the wire to the MC switch or e-brake is grounded. When you fix the grounded wire, you can put the bulb back in.

My guess is the brown wire to the e-brake is touching the chassis under the seat or throughout its run to the bulb.


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Posted by: vin man Feb 12 2017, 05:25 PM

If I do as suggested and remove the bulb, breaking the circuit of the flasher relay - will my turn signals still work? I removed the relay and the turn signals did not work.

I want to fix it properly and find the short, but in the interim, I don't mind pulling the bulb provided I will still have turn signal functionality.

Unfortunately, when it comes to electrical diagrams, I don't comprendo well.

Posted by: Rand Feb 12 2017, 05:44 PM

Isn't there a reset button on the master cylinder? Push while ebrake released. Sounds like something else may be afoot here, but seems like worth a try.
EDIT: Never mind. I see you looked for that but it doesn't have one?

Posted by: vin man Feb 12 2017, 05:59 PM

Doesn't have one.

Posted by: ndfrigi Feb 12 2017, 06:09 PM

i did remove the bulb from the gauge 4 yrs ago. no effect with my turn signal, emergency light works too.

Posted by: vin man Feb 12 2017, 06:15 PM

Thanks for that info. I'm going to try and disconnect/replace the switch under the handbrake. If that doesn't fix the problem, I will pull the bulb.

Posted by: Spoke Feb 12 2017, 06:51 PM

Removing the bulb will not affect the turnsignals. Porsche designers had the bright idea to double use the flasher for turnsignals and to flash the brake warning light.

I thought in the first pic the wire to the e-brake switch was disconnected.

Posted by: vin man Feb 12 2017, 09:47 PM

There is a brown wire with white tracer that is disconnected in the area of the e-brake. But I'm not sure if this is the wire that goes to the e-brake switch. I suspect it is since the same color wire is one of the 2 wires on the master cylinder. But I have not yet verified. I was thinking - since that wire is disconnected and the light still blinking, maybe it is not the e-brake wire, but instead a seat belt sensor wire?

I hope to identify the switch tomorrow eve and confirm that a wire is on it.

Posted by: vin man Feb 13 2017, 05:18 PM

#1 - pulling the bulb is not the answer. While I no longer get a flashing light on the dash, the flasher relay does make a noise. It flashes much faster - almost sounding like a fuel pump.

#2. There is no switch anyplace near the hand brake that I can find.

http://s304.photobucket.com/user/e065206/media/Our%20Cars/1972%20Porsche%20914/B0B75260-EFB0-44CF-96DC-2EC17252761E.jpg.html

http://s304.photobucket.com/user/e065206/media/Our%20Cars/1972%20Porsche%20914/2525840A-8A40-4488-9D1C-54605FA657FC.jpg.html

That experiment also didn't work out for the relay. It smoked. Now I need to see if I can find a new one.

Edit: This is the start of problem number 2 - no turn signals or any systems using the flasher.

Posted by: ndfrigi Feb 13 2017, 05:24 PM

or maybe the noise is for the door when it is open there will be sound or for me it is a noice.

Posted by: Dave_Darling Feb 13 2017, 06:05 PM

The door-ajar buzzer does not sound like clicking. It really is a buzzer--in my car, a really pathetic buzzing sound, but still buzzing.

The brake warning light circuit will blink when one of the brown/yellow wires attached to the light gets grounded. That provides the ground path for the light, and for the flasher relay, which will start clicking.

There should be two brown/yellow wires attached to the light, one going to the button under the hand-brake handle (see photos upthread) and one to the switch in the master cylinder. The handbrake button grounds the wire going to it when the button is NOT pressed. So if someone dismounted the button and it is flopping around somewhere, that will cause the light to flash.

--DD

Posted by: vin man Feb 13 2017, 07:45 PM

New relay will be delivered on Wednesday.
switch for handbrake will be delivered tomorrow. I don't know exactly where to mount it but I'm just going to connect the wire and hold it against the floor and see if that impacts the light (once I get the new relay).

Posted by: vin man Feb 14 2017, 12:16 PM

I just wanted to add some more information on what happened when the relay fried:

First of all, there are 2 red lights at the top of the gauge. The one that has been flashing is the one on the right (1o'clock position). See the video for the refresher.

There is also a bulb on the left side (11 o'clock). There was no bulb in that fixture, but a few wires that connect to it.

I pulled the bulb on the right and powered up the car. There was no flashing (obviously), but the relay did click. Not at the same rate (turn signal rate), but a lot faster. Almost (but not quite) constant.

I pulled the gauge panel back out and saw that one of the wires on the left gauge has broken. I touched it to the broken connector and the fast flashing stopped, but I also blew a fuse.

Replaced fuse and tried again, this time the relay fried.

New relay coming in today or tomorrow along with switch to mount on floor by handbrake. I plan to mount the switch, connect all the wires and insert bulbs, replace fuse and see what happens.

If still flashes, will pull bulb and see what happens.

Posted by: vin man Feb 14 2017, 03:50 PM

Well now I'm really baffled. I replaced the relay, I reconnected the broken wires, put the bulb back in and now the flasher relay doesn't work at all. The turn signal comes on, but no flashing.

Fuses are good. I hate electrical problems.

Posted by: 914_teener Feb 14 2017, 08:17 PM

Man...ya get bonus points.

Keep at it.

Have you "rung" out every wire for continuity and then checked the ground points.

Also...how bout the wiring?

For years my windshield wipers didn.t work correctly. Turned out after I replaced the fresh air fan some DAPO had scabbed on a connector to the switch and shorted one of the hot leads behind the cowl.

Hang in there check the wiring diagram and physicaly check every wire if you can get to it.

Posted by: Spoke Feb 15 2017, 12:10 PM

Where did you get the flasher relay? I don't see it on Pelican.

Can you put the old one back in to see if it works?

Hopefully you didn't button up the fuse panel after installing the new flasher.

Flasher EP26 can be purchased at many FLAPS and is LED-compatible if you decide to go that way.

Posted by: vin man Feb 15 2017, 12:32 PM

I got it from Parts Authority. They usually have the parts I need for my VW or Porsche projects.

Autozone also has one. This is the one from Autozone: https://goo.gl/VhNiDZ

The one from Parts Authority has same pins and numbering, but the plastic housing looks a little different.

Parts Authority counter man is also pretty knowledgeable. He said I could use the 3 pin relay and jumper the missing pin location (showed me what to do) if I wanted to use $4 relay instead of $15. I went with the 4 pin to be safe.

Posted by: Spoke Feb 15 2017, 02:50 PM

Did you try re-installing your original flasher. Quite honestly the flasher does very little besides flash when you put the turnsignals on. If your original flasher flashes the exterior bulbs ok, there is nothing wrong with the flasher. Likely you have some wiring issue external to the flasher.

The link above takes me to partsgeek.

Autozone doesn't list a flasher or hazard relay for the 914 although it has some other interesting items for the 914.

I was wondering why my 914 is so slow. Maybe I need a new Nitrous Controller.





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Posted by: vin man Feb 15 2017, 03:00 PM

The autozone part is the exact one from Parts Geek - the URO brand. They crossed that number and got me the same part.

Nothing blinks. When I turn on the left turn signal, the light comes on and stays on - does not flash/blink.

Smoke came out of the original relay. I did retry it - no good.

Posted by: Spoke Feb 15 2017, 04:05 PM

What is the part number on that blinker. Not the partsgeek/autozone number but the part number on the flasher or packaging?

Pep Boys, O'Reilly, Autozone, Advance Auto, Rock Auto, etc., have EP26 on their websites and may have it in local stores. I've found them at some of my FLAPS. Pick up an EP26 and see if it works in your car.

https://www.pepboys.com/product/details/9103511/00199

Posted by: vin man Feb 15 2017, 08:35 PM

A few pics.

The first is the original relay that smoked. Part number on the relay is TBB264DB 002479-01

http://s304.photobucket.com/user/e065206/media/Our%20Cars/1972%20Porsche%20914/0C3D44EA-5CCE-461C-83A3-5000E0F957F9.jpg.html

http://s304.photobucket.com/user/e065206/media/Our%20Cars/1972%20Porsche%20914/D2FC1109-3272-4847-B194-3C3B4D1F819B.jpg.html

The next relay is the one from Autozone. p/n 91461830311E

http://s304.photobucket.com/user/e065206/media/Our%20Cars/1972%20Porsche%20914/60D388B7-CF5E-4666-8507-DF6A68CE6EBA.jpg.html

Finally the one from BAP/Parts Authority. DNI 0831/41
http://s304.photobucket.com/user/e065206/media/Our%20Cars/1972%20Porsche%20914/18ADF04E-44B2-4AA1-A23B-58AF6C6F5BC5.jpg.html

Posted by: Dave_Darling Feb 15 2017, 10:23 PM

URO... Not exactly the highest quality.

I believe that the original flasher relay has multiple contacts in it, one to run the external lights and one to run the indicator in the tach.

Different years may have used different flashers, though. I don't really remember.

--DD

Posted by: vin man Feb 16 2017, 08:35 AM

I returned the URO POS.
No progress last night. I'm going to start looking for professional electrical person to tackle this. Either that or replace the whole harness.

Edit:
What I accomplished last night.
#1 - Realized the URO relay was junk. fell apart first time I installed it than pulled it out of the socket. Returned to Autozone.

#2. Put everything back the way it was including the old relay. When I turn key on, the orig relay would click superfast. blinkers did not work.

#3- tried the BAP (DNI brand) relay. Blue the fuse.

I'm really electrically challenged and super frustrated. I followed all wires and did not see any that were melted/fried. The fuse that blows is position 8 in my fuse block. When I look at the wiring diagram for a 72, the colors of the wires on both sides of position 8 in my car actually match what is show in postion 9 in the diagram. on 1 side, 2 black wires. On the other side, 1 black/yellow wire and 2 red with white wires. Not sure why they are in different position but I would suspect it doesn't matter as long as both sides of the fuse are the proper wires.

When I follow the diagram, wires go to the headlight switch and/or hazard switch as well as the relay board. Headlight switch is not a auto parts store part which means time and money to replace. I haven't looked for hazard switch yet and don't even know if either switch is bad.

If there is anyone that is in the Phoenix area and loves electrical troubleshooting, I'm happy to give them a challenge and pay for their time.

Posted by: vin man Feb 16 2017, 10:18 AM

Anyone have a recommendation for a person/company that can troubleshoot automotive electrical? I want to get this issue resolved and honestly don't want to keep trial and error day over day. Need to have someone that knows this stuff diagnose and fix and be done.

-Frustrated Vinny

Posted by: scallyk9 Feb 16 2017, 05:45 PM

Hmm. I've got a similar problem with the indicator light not working, and ordered a new relay. It arrived as a Wehrle #914-618-303-11/206. It looks the same as what it is replacing. None of the numbers match anything mentioned so far. I have a '74 2.0 and I know earlier models had a different relay but I'm not sure of the changes in circuitry. Hopefully, this one will work and the earlier '72 models are different. Is my assumption correct?

Posted by: vin man Feb 16 2017, 11:03 PM

Got it working!

An electrical genius I know was able to come tonight and spent about 4.5 hours tracking it down. He knew it was going to be something stupid, but not sure what.

He came to realization that it was ground related pretty early on. Then just started tracking circuits.

To avoid blowing fuses, he took an 1156 light socket and bulb and ran that between the to ends of the fuse. This way, we would have power, but not enough to do any damage.

Turns out that one of the light sockets had shorted out. I have removed the light socket for both the flashing brake light and, I believe, the flashing seat belt light.

With the new relay, I've now got working turn signals!

My hazard light switch appears to be damaged so I'll have to source a new one of those, but it doesn't affect my ability to drive the car. I've also got to replace my high beam/low beam relay as it is sticking.

I'll post some pics tomorrow. I was wiped out and left the workshop a mess and the car in pieces. But happy!

Posted by: vin man Feb 19 2017, 12:55 PM

Problem #3

Premature celebration.

On Friday night I put everything back together. Over the very rainy weekend, I have been trying to get the car ready to the point I can drive it to a car show on Tuesday. Little things like door handles, window cranks, window regulator, windshield trim...

Today, I got door panels back on and wanted to take for a quick drive. Battery dead.

I put charger on the battery and tail lights immediately came on. I got in the car and pressed brake pedal - couple lights on dash came on and electric fuel pump started running.

Only electrical thing I've done is replace the headlamp relay. The original 4 pin was sticking and I got a 5 pin replacement. Followed the instructions from another thread to ensure I wired it properly. Don't believe it is the relay. Maybe I bumped something else when putting everything back.

All fuses are good. I need to track down my electrical genius again....

Posted by: vin man Feb 21 2017, 08:48 PM

Update:

I was concerned that maybe I did not wire up the new relay for headlights correctly. Rechecked and is correct.

I didn't realize this at first, but it isn't just the tail lights that are on, but also the headlights. I didn't notice before because they are retracted, but they are powered up when I have the battery connected to the car (even without the key in the ignition).

I tried removing the relay all together, and the head light and tail lights are still on all the time.

I started checking the ground locations. I found one at each headlight, and one close to the relay board. They all look good and no broken wires.

Now I'm wondering if maybe the headlight switch has gone bad? How would I test that theory?

Posted by: Dave_Darling Feb 21 2017, 10:55 PM

Unplug the switch?

--DD

Posted by: vin man Feb 22 2017, 04:21 PM

Will give it a try tonight. I don't think the headlights would work at all without the switch so I'm sure that will cause them to go out. The question is more of "how do I know if the switch is broken?"

Posted by: 914_teener Feb 22 2017, 04:56 PM

You rule each thing out.

You test input and out put voltage first with a meter.

You will need a wiring diagram and an analogue or digital voltmeter.

Then you test the wiring output.

Then you test the device.

It is a process of elimination....like a logic diagram or test.

To answer your question directly:

By testing it.

Posted by: vin man Feb 24 2017, 09:18 PM

Ruled out headlight switch and brake light switch.

Going to pull the gauge cluster back out tomorrow and see if something there is shorting out.

Posted by: vin man Feb 28 2017, 03:37 PM

ok, issues 3 (and 4) resolved.

After resolving Issue 2 - the flashing brake light, I did 2 things. I replaced the headlight relay and then put everything back together and reinstalled the upholstery.

I had replaced the original 4 post headlight relay with a 5 post relay. http://www.914world.com/bbs2/index.php?act=ST&f=2&t=304971
I had found some info on the Samba website that said that I should just run a hot wire to post 30, and therefore not have to run a jumper between 30 and 56. This was not the case. A JUMPER was REQUIRED. I removed the constant power to 30, put the jumper in place, and the headlights were no longer always powered regardless of the key position.



Issue number 3 was that my brake lights were always on and, when I depressed brake pedal, I was also getting some lights on the dash and power to the coil.

I caused this problem when reinstalling the interior. I had screwed the plastic housing that holds the armrest through the floor. When I did so, I went right through the main power wire, nicked the brake light wire, and possibly exposed a couple others as well.

I did a lot of troubleshooting and have a much better appreciation of the electrical system and also much more comfortable reading those wiring diagrams. Really helped a lot to blow it up to 3 foot by 4 foot and stick to the wall as me and a buddy worked through the circuits.

Car is all back and buttoned up. Drove it today and very pleased!

Posted by: mgphoto Mar 1 2017, 09:24 AM

There are 2 diodes behind the combo gauge, the brake light uses 2 separate circuits, the diodes prevent the current flowing in the wrong direction.
This is according to the factory wiring diagrams.
I have the same problem, just pull the wires to the switch on the master cylinder, tape them up, flashing stops but brake warning light will not light as the pedal goes to the floor, the light will not help in that situation, as you already know the pedal is going to the floor!
PS: get a 911 flasher, ground the common from the flasher and watch your individual turn signal indicators flash on the gauge in the direction you are turning.
Mike