1968 911 wiring question/problem

[teveo]

My '68 911 is being put together after having been apart for restoration, paint and modifications.

I do have a few questions I could not find answered in the forum. I checked the L57 and L59 wiring diagrams but with no success.

Background, the car had a slight enigne burn before I got it and I decided to make a 911R(eplica) our of it.

The po's had messed with the cabling but not that bad really, I think I have sorted out this and redone according to diagram L57 now.

I do have all the lamps and instruments hooked up and tested, wipers and light control ok, starter-relay cabling ok, charging system cables ok but engine is out so no testing yet
and plan to use the newer digital 6 MSD ignition as my resistor/resistor relay was burnt out.

Problem and extra cables
The relay close to the (smuggler box) fan is making alot of noise, had to unhook the earth to quiet it, I do find this relay in any diagrams, anyone familiar with this one?

Sorry for cellphone photos and garage dust.


Not a big problem but fogs are not working yet, this must be the foglamp relay (yellow), correct? (the small extra relay may be aftermarket but it was not connected).


Two green cables from the tunnel, have no idea and my best guess is that they went to the heated rear screen?



Head, flash and parking lamps soon to be hooked up but wires are "live".


The car as it sits, not very far from being roadworthy.

I've the same additional fan in my smugglers box of my '68 912 and if I'm right, the relay is for driving the fan motor. The fan was an option, like the Webasto heater, and therefore not found in the wiring diagram. The relay is usiualy mounted under the dash, just behind the fan and fog light switches. The fan switch is also situated in that area. Check/replace the relay. The noise could be caused by a bad ground/earth or switch contact.

The yellow relay is indeed likely the fog light relay. The yellow relay is used to enable the fog lights to be switched on only when the low (or high) beam is switsched on. In many countries it is/was not allowed to drive with only fog lights on. They only where allowed to be used in combination with the H/L beam. Perhaps this is the reason why the fog lights did not function as you expected. So first turm the H/L on. The relay switches +12 V to the fuse box, where two green/white wires are used to feed the fog lights.

Looking at the picture the second relay is indeed not connected. It would be guessing what its pupose was. It is not a more or less standard mod/addition.

Regarding the green wires I would say: look at the other side of the tunnel and check where they end. Could it be that they are to be used for the oil level sender? At least one of them? Oil pressure and level are both green with a colored band.

I hope this helps a bit in solving your wiring problem.

Otto

[teveo]

Thanks, I am not sure if I will use the original fan but could perhaps keep that relay and hide away a smaller modern fan for "rainy days". I plan to use an Odyssey battery in the smugglers box. It struck me that one of the green cables in the rear must be for the oil tank level.

As of today my rear harness is cut before the original split, ... should it not split just around the upper mount around the left rear shock? Splits into the right rear lamp, the oil pressure and the oil tank into a separate loom from around that location? Not?

[JT912]

It has been awhile since I dealt with this relay, but here is what the factory relay looked like. I don't remember what it controls.

[JT912]

I am at work looking throught my photos and found another that shows where that relay is located. In the upper left you can see the wires for it.

[teveo]

Yes, that is the one. 3 red cables, one of them with a white stripe and the brown ground.

The fan switch has two positions, I do not think switch has a builtin resistor so the relay must somewhat regulate speed then, builting resistor?

In diagram SL33 or 35 the later style regulation is three step with resistor ( the sliding handle ) but L57/59 does not mention anything.

In the later style diagrams there is a green/white for rear foglights, perhaps the 911L model had this as well, I can always check..

My car did have (aftermarket?) condenser and some AC lines, and it does not have a fresh air fan but that was maybe not std in 1968?

Just found a link with description, maybe worth looking into:
HELP 66 Early Fresh Air blower wiring

Up to '68 there was no standard fresh air fan at all. They offered the Webasto fresh air fan like yours. The later 69> standard type fresh air fan is completely different, controlling as well as the mechanical part. It's not situated in the smugglers box, but under the dash, near the wiper motor.

If you want I could take some pics of my '68 Webasto fan terminal block. It could make connecting a bit easier for you. Just let me know.

John's picture from the relay is correct. I could upload exactly the same one from mine.

Do you have the original switch, for operating the fan, mounted in the dash? And the fog light switch?

Otto

[teveo]

Thanks Otto, I think the terminal block is ok as it has not been touched and perhaps the original fan is going out for a smaller unit.

The terminal (spade) numbers on the original relay would have been nice to know. Maybe its a a special configuration on the relay? Could be mine is just trash of course.

I do have the original switches in dash. I am not going to use the fogs though, I am replicating "S-04516".

I have had a few early 911's (69, 70 and 72) and am familiar with the later fresh air system, I just could not remember how it was on the SWB cars, last time I had one was back in 1996.

Have some 150+ photos during the "makeover" (+ some for reference) here:
911L_to_R Photos by vanvinkel | Photobucket

In the end of the album ( page 7 & 8 ) there are photos from when I started taking it apart, must be 3, 4 or even 5 years ago.

I've made some picture and hope they will be a help to wire your fresh air blower. The wiring from my '68 912 has never been touched and the blower functions as it should.

The blower can operate at two different speeds. The switch in the dash therefore has three positions:
Pushed to the dash - OFF
Pulled to first "click" - LOW SPEED
Fully pulled - HIGH SPEED

The wiring of the back of the switch is shown below. Looking at the switch, a control light could be installed, but the wiring and fitting are not supplied. Perhaps someone (John?) could confirm the absence of the light and wiring:



Relay terminals:
85 and 86 - coil terminals
30 - mother contact
87a - connected to 30 when not activated
87 - connected to 30 when activated

The wiring of the relay:



Below the fresh air blower in the smugglers box and as a detail pic its terminal block:





The following is the most important info, I guess. I found the following wiring diagram for the blower in the 911 factory manual. So basically copyright protected.



And as a last picture my cocoa sunroof 912 from where the pics are taken.

I hope this helps wiring your fresh air blower.

Otto

Sorry, forgot to upload my 912 picture:



Otto

[teveo]

Thanks, that is a beautiful 912!

This info will be handy, especially the coil shared on the heater relay would have been hard to figure out! The newish MSD digital 6 ignition still need a coil.

Hope to get some time to work on the electric system later this week, I ordered suspension parts from our host last week and next week I will try find time to work on suspension. (My vacation is running away between house painting/maintenance at home and playing at the garage. )

(My vacation is running away between house painting/maintenance at home and playing at the garage. )

It's exactly the same here! Before you realize it's there, the rainy and windy season has arrived and the paint work is still not finished. Next spring .... ?

At the other hand, during the paint work a lot of Porsche ideas come up and other are solved.

If you need any additional info, just let me know (PM).

Otto