Cigarette lighter powers wiper on
 

I don't know since when but when I activate cigarette lighter for example by sticking USB power port in, the wiper comes on.

Is this another German design? Any idea how i could de-german this?
i'd start tracing the wires...

:lol:

That's funny. I'm betting your wires are crossed under the dash.

Quick hijack: I always wanted to use my lighter for a USB charger, but I thought you had to do some sort of retrofit to get it to work with US plugs???

Does anybody know if it is safe to plug your USB charger into the cig lighter with no retrofit?SmileWavy

I use a modern port wired to the battery with an inline fuse. The Porsche lighter port is larger than the US models.

Joe Bob... Can you post a picture of how your cigarette lighter looks. I would like to keep mine original looking, but I like the idea of using modern parts underneath. Perhaps you found a way to save the big cigarette button???

I went to AutoZone and bought a cheap after market 12v port. It's mounted under the ashtray.

I don't use the lighter but it's in there to fill the hole.

I HAVE heard that replacement US ciglighters will fitin the stock location.

Here's an inexpensive and reliable way to retrofit your Euro lighter socket to accept US plugs:

http://forums.pelicanparts.com/porsche-911-technical-forum/612310-dr-bulczynski-3-2-cigarette-lighter-mod-5-99-a.html

I'm betting on crossed wires, too. You'll need to get under the front trunk, disconnect fresh air hoses and remove the fresh air plenum to get to the cigar lighter wires. Not too bad of a job, you'll just need a little patience.

Hilarious. If I pushed the lighter and the wipers came on, I'd laugh myself into a phone pole...

Very interesting. The Cigarette Lighter is fuse 6 R/Bk. The Windshield Wiper is fuse 7 R/Bk, which changes to R/W. Both share a Common Ground from the diagrams. Possible backfeed if chassis ground is bad. I would check to make sure the connections are correct.

I think Sully is on the right track. I had a somewhat similar dilema a while back. When I
would activate the left turn signal, my wiper would "take a swipe". Drove me nuts, because it made no sense!
Turns out it was caused by "backfeed" due to a floating ground. I tracked and traced with volt/ohm meters till I discovered the problem. The bundle of ground wires located on the front bulkhead (where the neg cable from the battery goes) was where the culprit was located. When I unbolted the bundle of connecters I found corrosion between a couple of them, causing the floating ground, ergo the "backfeed"
I cleaned up all the brass terminal ends with some emery paper, hooked em back up, and VOILA problem solved! Either a "ground loop" or floating ground in these cars can cause weird and unexplainable symptoms!
Good luck,
Grant

Bad chassis ground. The wipers are finding a ground when the lighter is engaged.

I am suspecting the lines of sully, uwanna, and thumbdoc. i'll find time to get myself upside down in the foot well. my neck hurts just thinking about it.

First thing I would do, is open the hood, follow the negative battery cable to where it bolts to the body. That's where you will find the "bundle" of brown ground wire connectors. Remove the nut and all the wires. Then clean up all the connector ends with some emery paper. If you indeed have a "floating ground", that is where it will most likely be located, as that's where all the grounds for the interior come together. No need to crawl in the footwell and "hurt your neck".

I had the same symptoms with my 83SC when I bought it last year. I plugged a GPS into the cigarette lighter on the way home and the wipers activated. The issue went away on its own, but I suspected a floating ground somewhere. Over the winter while I had the windshield and dash out I found a loose ground behind the heater controls. This is a ground point for most everything in the dash. I cleaned and tightened up the spade connectors along with cleaning the main ground strap from the battery to chassis along with pulling each fuse in the fuse block and cleaning those. I noticed an immediate improvement with the brightness of my dash lights as one benefit to doing this. Warren

I think E Sully has it.
Check the wires grounding to the chassis stud that is right in front of the battery. If there are any grounding issues there the wiper can go crazy.

went to check the ground stud at the other end of battery ground strap. indeed found a bundle of brown ground wires. scrubbed the corrosion off with emery paper, put everything back, and... wiper works! but not in the way i like, ya know...

in fact, what i see is that the wiper does not come on by itself. i put some device in the cigarette lighter drawing power and turned the wiper on then when i turned the wiper off, it continues going.

dammit.

i go check the bentley manual to see the ground schematics.
yes, the grounding is shared between wiper motor and cigarette lighter but it leads to a ground stud not at the battery but to the stud behind the brake booster and vent blower casing. okay. found it. but the space is tight and was much more cursing than the battery side stud. removed the hood strut and one of the vent hoses but not much help. i just kept telling myself "patience," and i eventually got the contact points cleaned and put everything back together...
...except to get the thing fixed. the wiper still won't turn off when i have power at the cigarette lighter.

dammit, two...

i'll go look for other ground points like the one wolds suggests.

if someone know any spell i should know and use, please let me know. i do believe in witchcraft.

In my earlier post I suggested inspecting the ground point behind the heater controls. On the schematic it is G206. I'm pretty sure that that is where the cigerette lighter goes to ground. You will find several brown ground wires going to it including the radio and dash lights. On my car they were loose. You can easily get to it by looking under the dash from the drivers side. If nothing else you will be confirming that the grounds at that point are electrically solid. I can tell you that it is on my short list of things to do to check all ground points on the car. Loose grounds are a sure recipe for all sorts of issues including fire. Warren

Thanks, Ed. Yep, the same diagram i'm looking at. Off to get to G206.
i think the two posts i referred to earlier are G106 and G116. G116 however was not under the fuel tube. It was more like between the blower housing and instrument panel, just in front of flasher and other elec components are. I might have missed one under the fuel tube, i'll go look. I did see G104-like ground right behind the fuse box with two black wires, not brown. This was not a post but a self tap screw holding the wires. I'll go look if there in fact is a post like G106 and what i though was G116.