Whoops! Tried to jump start with cables on wrong way around!
03-16-2009, 02:42 PM
#1
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Whoops! Tried to jump start with cables on wrong way around!
A friend of mine has a 1990 964 C2 tip.
He recently needed to jump start his car. Unfortunately he connected the jump leads the wrong way round https://rennlist.com/forums/graemlins/banghead.gif
Now the sppedo and the odometer have stopped working and the spoiler will not raise, although the car seems to run perfectly.
Has he blown a fuse (or a relay) or has he done something more serious?
He recently needed to jump start his car. Unfortunately he connected the jump leads the wrong way round https://rennlist.com/forums/graemlins/banghead.gif
Now the sppedo and the odometer have stopped working and the spoiler will not raise, although the car seems to run perfectly.
Has he blown a fuse (or a relay) or has he done something more serious?
03-16-2009, 04:45 PM
#2
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I don't know if the 964 instruments and controls are reverse-polarity protected. For sure he risked damaging the battery and the wiring harness. Did the donar car sustain any damage?
A 964 has a lot of electrics and electronics, and I would want to verify everything was working correctly. The best and quickest check is to get a Hammer and read the diagnostic codes, sensor values, and operate the actuators (you can exercise the resonance flap, servos, and injectors). How is the climate control working?
The spoiler is triggered by the speed signal, so fixing the speedo should also fix the spoiler. Do the manual spoiler controls work? For sure, look at the fuse chart on the inside cover of the fuse panel. Locate the instrument panel fuse. If that is blown, that is an easy fix. I would still want to check the rest of the electrical system.
A 964 has a lot of electrics and electronics, and I would want to verify everything was working correctly. The best and quickest check is to get a Hammer and read the diagnostic codes, sensor values, and operate the actuators (you can exercise the resonance flap, servos, and injectors). How is the climate control working?
The spoiler is triggered by the speed signal, so fixing the speedo should also fix the spoiler. Do the manual spoiler controls work? For sure, look at the fuse chart on the inside cover of the fuse panel. Locate the instrument panel fuse. If that is blown, that is an easy fix. I would still want to check the rest of the electrical system.
03-16-2009, 04:51 PM
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Not sure it would make a difference or not, but how long did he leave it connected incorrectly. Happened to me once for about 2 minutes before I realized it. It blew the traction control fuse and the radio fuse. Got lucky I guess.
Carmelo
Carmelo
03-16-2009, 05:38 PM
#4
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I did this once myself. 
I got lucky that I only burned up one wire, but yours sounds much worse.
If memory serves, when you reverse the terminals the first thing to short will be the ground cable to the alternator and the shorts will spread depending on how long you left the key on with the cables reversed. If you feel confident checking everything out yourself, pull the alternator and start checking the harnesses from there.
I got lucky that I only burned up one wire, but yours sounds much worse. If memory serves, when you reverse the terminals the first thing to short will be the ground cable to the alternator and the shorts will spread depending on how long you left the key on with the cables reversed. If you feel confident checking everything out yourself, pull the alternator and start checking the harnesses from there.
03-16-2009, 11:17 PM
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A friend of mine has a 1990 964 C2 tip.
He recently needed to jump start his car. Unfortunately he connected the jump leads the wrong way round https://rennlist.com/forums/graemlins/banghead.gif
Now the sppedo and the odometer have stopped working and the spoiler will not raise, although the car seems to run perfectly.
Has he blown a fuse (or a relay) or has he done something more serious?
He recently needed to jump start his car. Unfortunately he connected the jump leads the wrong way round https://rennlist.com/forums/graemlins/banghead.gif
Now the sppedo and the odometer have stopped working and the spoiler will not raise, although the car seems to run perfectly.
Has he blown a fuse (or a relay) or has he done something more serious?
