Need help from SWB owners- Electrical

[john_cramer]

Ladies and Gentlemen,

I have encountered some electrical issues with my '66-- seems that the silver can hazard flasher has finally determined to throw up its hands. Naturally, it's NLA from Porsche, but fortunately, it's located beneath the drivers pdeal board, so replacing it with a modern functional equivalent is an option. With the shift to LWB they integrated the blinker and flasher in a single unit, which would require rewiring, etc. I'm collecting information to do that over on Pelican, http://forums.pelicanparts.com/showt...12#post1963212

Anyway, I'm wondering whether any of you SWB gurus know definitively the function of three relays in the car. Two of them are shown in the attached photo, and are located under the pedal board. The other one is in the trunk, way up by the fuel gauge, fastened to the trunk floor with a couple of screws.

I THINK I have it narrowed down which is which. Unfortunately, identifying them by the wires is difficult-- as some PO painted the wires with undercoating, and using lacquer thinner to clean the harness also removes, for example, the green stripe from a white wire with green stripe-- making the fix almost as bad as the problem.

Also, if any of you have photos of these areas of your car, including the fusebox, it would be a big help to see what things are supposed to look like. Mine's a tangled mess, all original, but again, covered with undercoat. I spent the better part of yesterday chasing electrical gremlins-- and have only started to make progress as the attached photo shows.

Thanks in advance for any replies.

[mjmoran]

John,

Relays for early O and A series cars is as follows:

signal horn relay: has blk/ye wires on 30/51, br/wt on 89, red on 86/87 (87 goes to fuse #4)

Light signal relay: wt 30/56 and 56a, wt/gn 57, 56b ye, 89 br

control light relay (hazard): bk 30, gr/wt (2) 86, wt/rd (2) 85, rd 87a

I do not have either of my SWB cars here, so I cant tell location right now, although from the diagram in the factory manuel it looks as the horn and the signal relay are the two under the board and the other in the trunk. There is another relay in the engine compartment, but this is unrelated.

Hope this helps...

[hdavis]

Here's my fuse box, which except from some left over cables from a car stereo, is -I think, quite unmolested, hope it helps.

[john_cramer]

Mike, Henry, thank you very much. That's a big help just to confirm what I have to do.

Here's a good 912 shot I found, should be same as ours. With full credit here: http://www.hillmanimages.com/912/ts_blinker.html

[mjmoran]

Great. I will take a look at my 68 this evening when I pick her up. Will post a picture if it looks to be helpful. Also, if you want a scan of wireing diagrames, let me know.

Cheers,

[john_cramer]

Michael, thanks for the offer. I actually have an 11x17 color print of the L57 diagram here, and also the later version.

The interesting issue is that Porsche went to an electronic/mechanical blinker relay with the SWB cars, which resulted in a change to the circuit design. I actually printed the '71 diagram also to compare the two. In the original SWB design, the hazard flasher had two separate output terminals for the left and right circuits. This was because it was wired in parallel with the turn signal circuit- such that if you pull the hazard switch, it simultaneously grounds the hazard relay, which cuts off power to the turn signal flasher, and grounds the hazard flasher, causing it to pulse +12v. . .0 . . +12v . . 0. Anyway, the L and R terminals from the hazard flasher are connected in parallel to the turn signals, so on go the lights. BUT if one were to substitute a modern three-prong blinker for the old four-prong, you would end up connecting both turn signal circuits together-- resulting in BOTH signals coming on when you put the stalk in either direction. . . I think an additional DPST relay, as often found in headlamp relays, would do the trick- . . . more later.

[john_cramer]

Well, I finally figured it out. I had to use two SPDT relays (although SPST would be fine) and a modern electronic flasher (Tridon EL13) to make it work.

Fortunately this is all hidden deep below the pedal board where it will never be seen, and the function appears identical (and the sound could be made identical, through use of a thermal flasher instead of electromechanical)

Cost was about $15 for parts, and about 27 hours of head-scratching and reading the wiring diagram.

http://forums.pelicanparts.com/showt...threadid=68155

[72tii]

John,

Do you think the attached picture of a BMW 2002 relay might work without the added relays?

My '68 911 has a bad turn signal relay and I'm just looking at options.

Thanks,

Mike

[nick-moss]

Maybe too late, but may help someone else. A RHD 68

[roblav]

It seems to me that many years ago, on one of my SWB cars, that I needed to replace that hazard flasher can - and that Lucas made one. Given British electricals, it worked fine.