Eric Dvorak

Being that I have the entire interior gutted for restoration I've decided to upgrade the sound system (XM Radio) and install the new DVD driven GPS system from Alpine, it calls for a wire to be tied into the speed sensor (VSS) but I can't seem to find it. The idea is to lay out all the power, RCA, antenna and any other associated wiring before the new interior is installed. So if any of my friends of mind and machine know of this wires location I would appreciate some enlightenment. <img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />

2V4V

Eric,

You are the proud owner of not one, but four, speed sensors.

There is one at each wheel. They are for the ABS. Also, on your MY, the speedo is driven from these outputs.

I assume this nav system is software adjustable to allow for differences between car types. (ie, they all have different ways of outputting speed. In fact, there was a change in the tooth count on the axles of the 928, but I'd have to look up when it happened.)

Not knowing what the sys reqs are on your nav system, I can't even begin to point you at the right place to tap into the system. Find out what kind of input it wants and let me know.

HTH,

Greg

Eric Dvorak

Thanks Greg, I installed a similar unit in my BMW and just yesterday put one in my Dodge Ram, I went to Circuit City and asked the roadshop guys which wires to pick on both the Ram and Porsche, they have a computer that gives them all the wires, there colors and locations for the install of an alarm, remote entry sys., GPS, remote starter, exc. I got both printouts and the one for the Porsche didn't specify any wire, the one for the Ram was a orange/ white off the side of the transmission, also they only could go back as far as 88' (mine is an 87'). I don't think it matters what freq. the speed pulses are because the GPS should know the speed of the vehicle, I know it has a gyro in it to keep track of the cars turns, braking and acceleration while out of sat. view ie: trees, tunnels or large building obstructions. My guess is that it uses the speed sensor for some relationship to the cars speed for these non sat. receiving times. I don't think the ABS wheel sensors are the ones; it's probably the one from the trans. Do you know the color of that wire? <img src="graemlins/wave.gif" border="0" alt="[byebye]" />

WallyP

The '87 still drove the speedometer/odometer from the impulse unit on the differential cover. Not a clue as to whether the pulse is suitable for your use, but the wire color is brown/red.

The best place to pick up the pulse is probably at the cruise control box not too far from the back of the radio in the center console. Same brown/red wire, goes to terminal #11.

Eric Dvorak

Thanks Wally, That sounds like the correct one.