From: darling@simlab.arc.nasa.gov on behalf of Dave Darling [darling@simlab.arc.nasa.gov] Sent: Monday, March 22, 1999 5:25 PM To: 914@rennlist.org Subject: Wiring thoughts (SB Relay, parking lights, alt light) While stuck at home last week, I spent some time examining the 914 wiring diagrams in the Haynes manual. (The fever made it quite an interesting experience--one I don't recommend.) I managed to figure out a couple of things. First, I traced through the wiring related to the Infamous 74 Seatbelt Interlock Relay. I studied the differences between the Euro and US diagrams, and came to a happy conclusion. You can completely disarm the relay, and have no effect on the rest of the car, in two fairly simple steps. Step 1: Unplug the relay and throw it away. Step 2: Permanently connect together the two thick yellow wires that run to the relay's socket. If you're optimistic, you can make a small "bridge" out of heavy-gauge wire and some male spade connectors, and plug it into the correct parts of the socket. But that won't keep moisture and corrosion out very well. So if you're somewhat more realistic, you can CUT the wires off of the socket, then either use a crimp-on splice connector and electrical tape, or solder and heat-shrink tubing, to permanently connect them. No more relay--you've just removed one potential "failure point" from the starter circuit. (And we all know that it needs all the help it can get...) The next thing I noticed was that you can disable the "parking light" feature of your turn signal switch. There are a few places where you can interrupt the circuit so that the side markers and rear lights will stay OFF when the car is off. Unhappily, none are that easy to get to. You can unplug the grey wire from the ignition switch. Or cut it, as long as you make sure that the ends cannot short to ground. Or you can unplug/cut this grey wire at its other end, at the turn signal switch. I think there were a couple of other places, but I don't re- member them right now. But the key is that you ONLY want to interrupt the path BEFORE the "ignition on" path joins with it. Finally, I did some tracing (when I was feeling better) of the wiring that goes to the alternator warning light. Mine has been glowing dimly whenever the headlights, brake lights, turn signals, etc., are on. The warning light compares the "switched power" voltage to the "field" voltage of the alternator. There are a couple of connections in the path of the "field" signal, but many more in the "switched power" path. One of these is fuse #9. I had already sprayed my fuses with contact cleaner and rotated them (as per Jim T's instructions), but that had no effect. Then I started the car, put the high beams on, the turn signals, and put a brick on the brake pedal. I measured a 0.12 V drop across the fuse. Not a good thing!!! So I turned the car off and replaced the fuse, which I *then* noticed looked a bit old and grotty. No problems since then. I also did some musing about the ignition switch, but I'll save that for a later date when I can organize the thoughts better. --DD Dave Darling 74 914 2.0 (VROOM!) darling@simlab.arc.nasa.gov <--- OR ---> ddarling@wgss.com "914: The Porsche Picnic Basket. A lid that opens on each end, and a handle in the middle.." -- CHD