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-   -   Small fire center console Neutral safety switch melted (https://www.thirdgen.org/forums/v6/772900-small-fire-center-console.html)

Mark RWC 09-22-2020 11:26 PM

Small fire center console Neutral safety switch melted
 
About a week ago after starting my Firebird 2.8 V6 automatic I noticed a smell of smoke after the engine started. It was soon apparent it was coming from the center console. Shut off the engine and went in to get a battery wrench since it was most likely electrical. By the time the battery was disconnect the smoke was getting worse. After lifting the shift plate there were small flames to go with the smoke. Was able to put fire out with a small fire extinguisher. The damage was limited to the shift plate, neutral safety switch and switch connector. The discolored yellow and purple wires must have been what melted the connector. I suspect there was arcing inside the switch. The starter was replaced with an AC Delco professional about one year ago. As the third owner it is likely the original neutral safety switch.
After trip to the junkyard to get the connector and another neutral switch to test with the wiring harness pins were removed from the melted connector. A very small mini straight screw driver worked better than the Lisle tool from the parts store for removing pins. After cleaning the pins that go into the replacement connector the replacement switch was installed. The car started right up and wiring remained cool. Used a DC clamp meter to test the draw of the starter solenoid on the large purple and yellow wires it reads 10 amps. That seems to be what is expected in the way of current draw. None of the other wiring in the area of the center console appears damaged. The only thing added is a power wire for the relay on the power antenna that connects to the stock radio.
This should remind me to always keep a battery wrench and fire extinguisher in every vehicle especially one that is over 30 years old. Below are photos of the melted switch and harness.
The DC clamp meter is shown connected and ready to measure solenoid current draw once the key is turned to the start position.
https://cimg3.ibsrv.net/gimg/www.thi...7d3873deaa.jpg
https://cimg5.ibsrv.net/gimg/www.thi...b74ec9aae3.jpg
https://cimg6.ibsrv.net/gimg/www.thi...7fa203e0c6.jpg
https://cimg0.ibsrv.net/gimg/www.thi...559fc1888c.jpg

cosmonautpg 09-23-2020 10:50 AM

Re: Small fire center console Neutral safety switch melted
 
Wow — glad you’re alright and the damage is repairable! Adding a fire extinguisher and dielectric wrenches for my 92 V6 to my shopping list now...

scooter 09-23-2020 10:54 AM

Re: Small fire center console Neutral safety switch melted
 
You likely already had the fire going before you disconnected the battery since there is no current through that switch unless the ignition switch needs to be in start.

At least you caught it before it destroyed the whole car, This is one reason I eliminated the high current through the NSS on the clutch pedal. Switches should not be carrying high current

Mark RWC 09-23-2020 12:33 PM

Re: Small fire center console Neutral safety switch melted
 
Scooter that is an excellent idea to remove the high current 10 amps draw from starter solenoid that runs through the neutral safety switch. Did you install another fusible link and high current 15 amp automotive relay to handle the solenoid current? It was likely arcing inside failed switch that caused small electrical fire.

scooter 09-23-2020 02:21 PM

Re: Small fire center console Neutral safety switch melted
 
For the clutch switch I just used the contacts as the ground connection for the VATS relay. So the relay will not transmit power without the clutch pedal depressed, operating the car like stock overall.
You could wire a relay to serve in a similar capacity with the automatic selector. putting a fusible link in line is a good idea, but you also have to know that it's there to troubleshoot. So if you transfer to someone it should be told


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