Cigarette lighter relay location?

[adam911]

I'm trying to get the cigarette lighter working on my 69E. I have power at the fuse, but not on the wire going into the lighter. I want to check for continuity between the live wire at the lighter and where it goes into the relay. I have tried the 4 relays under the hood, behind the clocks. I checked for continuity but didn't get any on any of the relays. If one of those is in fact the correct relay, then continuity could be the problem, but I'm not able to see the colour of the wires going into the connectors.

Any help would be appreciated.

[javadog]

Relay? You sure you have one?


JR

[porschenut]

Never heard of a relay for the cigarette lighter circuit. Check the wiring diagram if you have one.

[howard freeman]

There is no relay for the cig lighter.

[adam911]

Well, according to the wiring diagram there is one. Item 45 is the cigarette lighter and 49 is the relay. Power goes from fuse 3 to the relay and then to the cigarette lighter. I also have a newer diagram that isn't dated and doesn't show a relay, but the wiring is also a different colour on that diagram.

[T77911S]

i have never heard of a cigg lighter relay either. maybe you jumped a wire tracing the diagram?
if you could post the diagram that would help.

[fintstone]

Are you sure that you are not looking at a switch (ignition switch) and not a relay in your drawing?

[Shaun @ Tru6]

here's a schematic of the 69 wiring diagram showing the relay. The red/black goes to the cigarette lighter. Red/white is from fuse 3. Red bridge goes to the blower relay, 48. Brown goes to blower and headlight flasher relay switch.

[T77911S]

i have never seen a relay for the cigg lighter.

check at the relay itself. you shoule have power on 30 and 87a.
you can also jumper 30 to 87 and check at the lighter

[adam911]

I would check the relay, but my initial question was where is it physically located?

[adam911]

Wasn't successful tracking down the relay, as I couldn't find continuity between either the cig lighter and any of the visible relays or the wire at the fuse box and any of the visible relays. In the end I just used the power from the unused gas heater supply (which wasn't an optioned on my car) to power the lighter and did away with the relay. Both earlier and later cars didn't have the relay, so I decided to do away with it. The lighter now seems to work, but during my investigation I have created another problem. My ignition light fuel gauge, temp gauge and rev counter are working in reverse. The ignition light won't light up until the engine is running and the revs are increased. The rev counter isn't showing true revs and the fuel gauge moves slightly when revved hard. I've gone back over what I've been doing today, but cant rectify it.
Anyone have any ideas?

[James Brown]

i see it shawn, i see it, comes from fuze 3 to the lighter and the relay completes the ground (in typical german fashion)

[T77911S]

maybe the relay was on the drawing but never installed.
did you try checking to see if the hot wire went straight to the fuse?

[adam911]

Yes, I tried from both ends; fuse to all relays I could find and cig lighter to all relays I could find. So, either its is one of those relays and there's no continuity or I couldn't find the correct relay.
There aren't that many places to put a relay on those cars and apart from the 4 inside the hood on the drivers side I can't find any others. It's odd the pre 69 and the post 69 cars had no relay and it only shows a relay for the "E"and "S" 69 models, which makes me think perhaps it's something to do with the introduction of MFi and the associated electronics that go with that. A PO removed the MFi from my car sometime ago and it has Webbers.

[javadog]

I doubt a cigarette lighter relay would have anything to do with the introduction of MFI. I would just trace the hot wire from the lighter back to it's source. Tracing wires in a harness can be a pain but it's possible.

JR

[T77911S]

you checked the cigg wire to the relays. but did you check it to the fuse?

[E Sully]

I wrote this up yesterday to post on your thread and then saw that you found the wire at the ignition switch and I skipped replying. If there is a relay maybe some of the information will help, but there may not be one depending on production line changes. Also of interest is an old post of yours I responded to but did not have the diagram for, where the wiring harness smoked up and you installed a jumper wire to bypass the existing connection from the ignition switch pin #15. There could be more going on, but without being able to physically go over the car it is difficult. I am trying to go by the diagram linked to, but as you know there are changes made that my not appear on this diagram. With my 1973 the 1973 diagram is only partialy accurate, there is another one for 1973 CIS, but there is also another partial diagram for the WUR circuit that shows items not on the first CIS diagram. I wish I had the factory manuals for reference. Porsche makes you work to find all the facts.

Interesting thing is from what I see on the 1971 diagram they use the feed from fuse #4 to feed the cigarette lighter and also the Aux. heater with no relay the way you seem to have it wired now, but off of fuse #3.
Yellow/Red at the ignition switch terminal #75, travels to the Blower heater relay switch, then Red to Cig lighter to activate the relays when the ignition is turned to run. The feed for the lighter itself is a separate Red/White.
If the blower works then the feed to the Cig lighter relay should also be good, if not then the Yellow/Red might be the problem.
From what I see the Cig Lighter feed starts as Red/White at Fuse #3. Same fuse handles interior lights and the clock, by separate Black wire. If the lights and clock work then the feed to the relay should be OK and the relay itself may need to be replaced.
You say you used the Gas heater feed. Is this the Blue wire from or the Black feed to the optional switch?

This is the section where you found the wire off at the ignition switch and repaired, but is involved with the jumper you installed according to the earlier thread.
The feed for the Blue/Yellow starts as a Red on the ignition switch pin #15.
The Blue/Yellow wire supplies voltage to the gages, which gives a reading by varying the resistance to ground, depending on the sensors. The same Blue/Yellow feeds through the alternator lamp to the blue wire. This provides the voltage to the Alternator, by way of the regulator, to the field windings so that it can produce electricity. When the alternator produces electricity as it spins, the voltage across the lamp equalizes between the Blue and Blue/Yellow and the lamp goes out.
If the lamp is getting brighter then there is a voltage difference between the Blue and the Blue Yellow. What voltage do you get at the battery with the engine around 1500-2000 rpm? You may have lost the Blue /Yellow feed.

[adam911]

Yes Ed, it was the red wire at marked "15" on the ignition switch that I had knocked off. It was the one terminal that wasn't visible, so took some finding. And yes this all is most likely a legacy from when my brake light switch shorted and burned some of the loom, though I did strip it all out ultimately, or so I'd thought. I suspect I should be getting continuity between one of the relay connectors and the fuse 3, but nothing at all. However I could get continuity between one of the relays and the other wire that goes into fuse 3, which is the power to the clock. Can't see why the clock would be on a relay, but it appears to be none the less.
I have to be honest, I'm not entirely sure what these relays do. I understand the use of relays to switch circuits in commercial electrics, but don't really understand their application in auto electrics.