I'll try again...PLEASE help. speedo wiring. thanks

[jarrald]

OK-
I've been 'testing the water" so to speak of wanting to clean the inside glass on my gauges b/c of fogging (esp the tach). I can see a gunk buildup on inside of several. So, I took the clock out. OK. then I pushed from behind to pull the speedo. well, then I noticed one of the wires (white with red stripe) was disconnected. There are actually 2 white with red striped wires and one of them is connected. next to where this one is connected is a place to connect another wire (currently not used?). The white w/red stripe that is not connected is coming out of a wirebundle with a green wire and a brown wire. the white w/red that IS connected is coming out of a wirebundle with a red w/yellow stripe.

All gauges were working properly before I started. I have not tried them since b/c I wanted to get help first.

Question for anyone that knows and will PLEASE help: Is this white w/red striped wire an extra (unused) wire on this model? 1987 911 Cab (non-turbo). Or perhaps did I disconnect it while pushing out the speedo? Anybody know if this is an unused wire and connector on back of speedo or did I definitely unplug it accidently. Thing is: I unplugged the clock wires and it was HARD. I had to use pliers so this is why I think it might be an extra?
Thanks.
-afraid to start car before getting answer!

[Argo]

I'm no wiring expert, but I checked my Bentley's 86-87 instrument panel wiring diagram for you and it looks like there are 2 white/red wires both attached to the same point on the speedo (at least in the diagram). One goes to the convertible top control unit (to keep it from opening above a certain speed?) and one goes to the blower control unit (it doesn't say which blower). It also shows 2 greens - one to the upshift indicator and one to the speed transmitter. The diagram shows both these 2 greens attached at another point on the speedo (along with a black/brown going to the cruise control regulator). It shows the red/yellow going to the convertible top indicator lamp. The diagram is on page 970-80 for anyone who knows more about speedo wiring diagrams than I do. You're smart not to turn the key until you've got this figured out; frying a circuit would be an expensive PITA. Sorry I couldn't help more, but at least it gets your post bumped.

Argo
88 Targa

[jarrald]

thank you very much. I was trying to look at a Haynes book which is supposed to include my year but the wiring diags went up to 85 then stopped. it didn't show 2 white/red wires. but it also didnt show a few of the others. I'm a newbie at playing with my car. Is this Bentley book a much better book? My Haynes book seems terrible for Porsche. Haynes seems OK for my Saabs. I've never gotten anything out of the Haynes book for my 911. can you recommend books?

sounds like I should hook up the other white/red wire. I thought the top wouldn't move while ignition was in run at all, only in first position? the other wires are exactly as you describe. although there is another re/blk wire attached to same post as red/yellow you mentioned. but the 2 greens with br/blk are there together. only thing is that I'm starting to think that this 2nd white/red wire was already detached. no way I unplugged it. I was gentle. however, a Porsche dealer did have my speedo out a few years ago to recal it for my wheels when I bought it from them. wonder if they left it off.

[Argo]

Glad I could help. The red/black wire you mentioned goes to the ignition switch and is indeed attached at the same point as the red/yellow. It's in the wiring diagram; I just got lazy typing my answer. If the detached white/red wire looks like it has recently been attached (has a clean surface) I'd reattach it to where the other white/red is connected. If it were my car, I'd probably take the chance and reattach it there anyway whether or not it looks like it was accidently disconnected.

As far as reference books go, I found the Haynes manual all but useless for late 80's carrera's. I misplaced mine a few months ago and have never bothered to look for it. If you do semi-serious wrenching on your car, I'd invest in the Service Manual for Porsche 911 Carrera, 84-89, Coupe, Targa, Cabriolet by Bentley Publishing . It runs about $100 but it is extremely comprehensive (it took me 2 minutes to find the answer to your wiring question) and it would probably have cost you near that much to have a Porsche mechanic figure the wiring out for you. I've found it invaluable and it stays on the top of my Porsche service literature stack. If you are a weekend mechanic, I'd also strongly recommend 101 Projects for your Porsche by Wayne Dempsey. It covers all the projects you are likely to encounter in routine maintenance and mild upgrades for your car and is very clearly written with lots of color pics. It costs $30 and will pay for itself over and over. I've found that precious few mechanics care as much about getting a job done right on your car as you do, plus you save $$$ and get a nice sense of satisfaction when you successfully fix something yourself.

Argo
88 Targa

[jarrald]

Argo-
thanks again for looking that up. I tried the roof with and without the 2nd wire. worked both ways. the manual says only works when car is stationary in position one in ignition. I left the 2nd wire attached. drove around and tried the roof while in motion. nothing. oh well. either it is an extra wire or it came unhooked when I pulled it out. either way, nothing blew up....yet anyway!

thanks for the book info. I do plan on buying those. my Haynes manual really bites. it's aweful. maybe I can use it to prop up something in the garage!

[John St. Louis]

I am pulling my speedometer on a 1987 Porsche 911 to send out for repairs. I am having trouble removing the three separate wires that go in to the back of the speedometer in to the red round connections. I did not want to pull too hard on the connections and break them. I tried turning the red connectors 90 degrees to see if the wire would free up but it doesn't. Any suggestions? Thanks.

[nesslar]

I just answered you in the other thread; slide a knife blade under the silvery flanges that are right against the body of the speedo and pry up. Easy. They are lampholders and just pop/slide in and out. I did it with fingernails only one time. Lar