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Reverse Lights (Back-up/Neutral switch) Problems - Need Help!

This is a discussion on Reverse Lights (Back-up/Neutral switch) Problems - Need Help! within the Technical / Maintenance forums, part of the General Discussion category; Evening: I have a 1990 GMC Sierra 1500 truck with an automatic transmission. When I put the vehicle into reverse, ...

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    Reverse Lights (Back-up/Neutral switch) Problems - Need Help!


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    Evening:

    I have a 1990 GMC Sierra 1500 truck with an automatic transmission. When I put the vehicle into reverse, my back-up lights do not turn on. I have to move the shifter mid-way between park and reverse before they turn on. This wouldn't be a problem, but the reverse gear disengages sometimes because I moved the shifter too far over.

    I've had this problem since I've owned the truck. I went ahead and replaced the back-up light/neutral switch about 6 months ago. This helped, but didn't fix the problem. I've manually adjusted the piece, but I still can't seem to get it to work just right.

    I've searched the forum, but I've already tried the solutions I found. Does anyone have any ideas on what I can do? Thanks in advance.

    FYI: The switch looks like a plastic horseshoe that mounts on the steering column where it meets the firewall.
    Last edited by Striker; 04-17-2006 at 10:31 PM.

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    Re: Reverse Lights (Back-up/Neutral switch) Problems - Need Help!

    No one has any ideas, eh? =)

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    Re: Reverse Lights (Back-up/Neutral switch) Problems - Need Help!

    First see if you can get the reverse lights to fire by bypassing the reverse light switch. Do this by unplugging the wire that leads to the switch and then connecting a piece of wire to the terminals of the wire. This should cause the reverse lights to turn on (car may need to be on). If this works then proceed to troubleshooting the switch, if it does not, then troubleshoot the light circuit (bulb, ground, loose wires - especially if they've been tapped into for an trailer plug). To troubleshoot the switch, use a voltmeter as follows - connect a lead to each tang of the reverse light switch and set the dial to ohms. It should read infinity in park. Then change gears to reverse - ideally, the ohm meter will bounce to 0 and stay there when in R. Otherwise, note where the meter jumps and adjust the switch by sliding it left or right (it rotates and clicks to change positions of where the switch fires). You should be able to dial it in. Good luck!

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    Re: Reverse Lights (Back-up/Neutral switch) Problems - Need Help!

    The circuits are good - it's just that the amount of adjustment allowed in the switch doesn't seem to get him far enough. I haven't had that problem before so I was kinda lost on what to tell him. He's replaced the switch already and adjusted it as far as it will go.

    Richard

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    Re: Reverse Lights (Back-up/Neutral switch) Problems - Need Help!

    Puttram:

    I have checked and the circuits are indeed good. However, as someotherguy mentioned, I've adjusted it as much as possible with little effect.

    I'm not sure what else I can do at this point.

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    Re: Reverse Lights (Back-up/Neutral switch) Problems - Need Help!

    I am kind of assuming the adjustment you are talking about was on the switch you replaced? I am not sure about chevys, so someone may want to chime in with whether this is correct or not. But..... on most vehicles, if you take apart the steering column plastic covers, you should be able to adjust the shifting cable at the stem. This should line up your letters and indicator again, and hopefully help with the other problem. Maybe? LOL.

    JDPelfrey

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    Re: Reverse Lights (Back-up/Neutral switch) Problems - Need Help!

    You may be able to adjust the shift rod under the hood at the firewall.

    My '88 has a clamp bolt where the trans linkage attaches to the lever on the column.

    My suggestion would be to readjust the backup light switch to the middle of it's adjustment.

    Put the trans in reverse (key on, but engine not running).

    Loosen the clamp bolt at the firewall, and move the shifter lever until the backup lights come on, and then tighten the bolt.

    1988 C-1500 Silverado. Olympic White. RCLB, 5.7 TBI, 700R4.

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    Re: Reverse Lights (Back-up/Neutral switch) Problems - Need Help!

    Wondering what was the problem?? I have the same issue on my 1990 Gmc Sierra. If I take the gear towards park my lights come on. I know the bulbs, wires and switch arw good. What adjustment did you make?

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    Re: Reverse Lights (Back-up/Neutral switch) Problems - Need Help!

    Wow, this thread is almost 5 years old. It ended up being a combination of a few things. I had to reposition the backup/neutral switch. jpel3500's suggestion was the key. I had to remove the bottom panel under the steering column. There is a little metal tab that adjusts the gear shift indicator.

    That's about all I can remember at this point. I haven't had any issues to this day as the fix is still holding. Good luck!

 

 

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