Neutral position/Safety Backup light Switch Replacement

  • 2 POSTS
  • 5.9L
  • V8
  • 2WD
  • 155,000 MILES

Backup lights do not work. All other lights/signals work. No problem starting car in park or neutral.
I believe it is my Neutral position/Safety - Backup light Switch.
I have replacement questions:
1) General location - diagram would be great.
2) Trans oil: I read at one site I would need to have a drip pan under it and top off the fluid after replacement - does that actually apply to my make/model/year?
3) I also read that I may need to tighten switch with a torque wrench to 25 ft. Lbs. Does this apply to my make/model/year? And is the 25 ft lbs. Correct?

If I don't have to worry about trans oil coming out, I'd rather just go by the switch and replace it instead of going through the testing/bypass troubleshooting steps.

Do you
have the same problem?
Sunday, May 1st, 2016 AT 12:36 PM

1 Reply

  • 29,780 POSTS

That switch has been in the left rear corner of the bottom of the transmission, right above the pan, since the 1960s. It will have a three-wire connector. The fastest way to test it is to turn the ignition switch on, unplug the connector from the neutral safety switch, then jump the two outer terminals in the connector with a piece of wire or a stretched-out cotter pin. If you see a tiny spark when you do that, the switch is defective. The spark tells you current is flowing through your jumper wire, and it is going to the backup lights. If you can't see the spark, have a helper tell you when the backup lights turn on. When they do, you know all the rest of the circuit is working. You did check for burned out bulbs, right?

Use a new gasket with the new switch. It's a thin piece of metal. As a professional being paid by the hour, I never had time to fiddle around with a torque wrench. Use common sense based on what it feels like when you loosen the old switch. If you tug on the wrench with both hands for all you're worth, of course the threads are going to peel and something will be wrecked. There's no fluid pressure behind the switch, so simply snug is sufficient.

If you're worried about losing a lot of transmission fluid, when you raise the vehicle, (be sure to use jack stands), raise the driver's side a little more. When we do this on a hoist, we don't remove the old switch then stop to think about it. We stuff the new one in right away, so at most, we get a little drip on our shoes.

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Sunday, May 1st, 2016 AT 8:39 PM

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