Reverse lights

[renjaminfrankln]

I know this is a pretty banal subject

Tomorrow is the big day. Inspection. The reverse lights on the truck don't work, In NC there is a new law (this year) that says if the vehicle is originally equipped with white backup lights, they must be in operation.

It could be that both bulbs are burned out. I have to troubleshoot this tomorrow, I just noticed they were out today (got truck last Thursday). To test them I set the parking brake, turned the 'ignition' on (did not start) and put the selector in reverse. No lights

Of course I am going to check if both bulbs are burned out, but if anyone can educate me on other things to check, it might save me a lot of time. Is there a mechanical switch somewhere on the column that turns these lights on? Possibly there is a pressure switch on the transmission, and they work fine but didn't come on because the truck was not running?

1985 6.9 IDI 4x4

 

[Thewespaul]

What trans do you have?

 

[renjaminfrankln]

What trans do you have?

Sorry! That would be relevant. C6

 

[Thewespaul]

No worries I figured you had a C6 when you said pressure switch. Just wanted to be sure. You will have a switch on the trans that acts similar to a neutral safety switch. Pretty easy to test, but check your bulbs and fuses first

 

[renjaminfrankln]

No worries I figured you had a C6 when you said pressure switch. Just wanted to be sure. You will have a switch on the trans that acts similar to a neutral safety switch. Pretty easy to test, but check your bulbs and fuses first

Thanks. I went ahead and fired the engine up, and put the transmission in reverse with it running. No reverse lights. So i'll start with the bulbs and fuses.

Just to confirm, there is a pressure switch on the transmission that activates the reverse lights? So I need to crank the vehicle and have a helper put it in reverse to check if i'm getting any power to the rear bulb sockets.

 

[Thewespaul]

No it’s not a pressure switch, it’s just a regular contact switch just like a neutral safety switch

 

[renjaminfrankln]

No it’s not a pressure switch, it’s just a regular contact switch just like a neutral safety switch

Got it. Can you give any more detail as to the location of the switch. Is is on the transmission linkage near the trans?

Thanks, will help me out a lot tomorrow if the bulbs turn out to be fine..

I would not care so much about getting this done ASAP but I am in the process of moving across town and the cops don't take to kindly to a truck with no plate around here. I have to pass inspection before getting a plate.

 

[renjaminfrankln]

Found the switch on the left side of the transmission. 4 wires leading off of it. Hopefully it is just the bulbs and/or the inspection guy lets it slide

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[riphip]

Looks like your switch may have been moving or someone tried to adjust it. First try as you did before with E-brake on, key on/no start & shift into reverse. Have someone else watch the lights or place something at rear so you can see the lights if they do light up. Lightly loosen the 2 retainer bolts on the switch & SLOWLY move the switch up a hair (from what I see in photo) to see if reverse lights shine. Since it is cranking, the neutral safety switch is working but reverse lights (2 purple striped I think) switch is not. Hopefully it is just out of adjustment.

 

[renjaminfrankln]

Looks like your switch may have been moving or someone tried to adjust it. First try as you did before with E-brake on, key on/no start & shift into reverse. Have someone else watch the lights or place something at rear so you can see the lights if they do light up. Lightly loosen the 2 retainer bolts on the switch & SLOWLY move the switch up a hair (from what I see in photo) to see if reverse lights shine. Since it is cranking, the neutral safety switch is working but reverse lights (2 purple striped I think) switch is not. Hopefully it is just out of adjustment.

Thanks. I had time to pull the tail lights this morning. Was greeted by the sight of a brand new bulb! Multimeter shows no power getting back there. I will try adjusting the switch.

The switch is about $30 and I found one at an auto parts store near me. To replace it, do I just undo those two bolts and slide it off? I may go ahead and pick one up on the way home from work, I can always return it.

 

[Thewespaul]

Yes it just slides off the shaft, here’s what it looks like with it removed

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Don’t forget fuses!

 

[IDIBRONCO]

You could always wire in a toggle switch for inspection time. For that matter, you could keep it permanently and use it manually when in reverse.

 

[austin92]

You could always wire in a toggle switch for inspection time. For that matter, you could keep it permanently and use it manually when in reverse.

This is how I have mine set up. I got some replacements from superbrightleds.com and tied a small 6” led light bar in mounted under the bumper. Makes a nice work light and don’t have to be in reverse


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[renjaminfrankln]

Tried adjusting the switch, no dice. The old one was pretty nasty looking so I pulled it off. Verified good 12v was getting to the switch. Replaced and adjusted per this article http://www.mustangandfords.com/how-to/engine/1308-how-to-troubleshoot-neutral-safety-switches/

Reverse lights working great!

Only other lights out now are the side marker lights on the front of the fenders just above the front wheels. I got new bulbs for those. The old bulbs were burned out. Replaced them, expected to see light... nothing! I'm not sure these are required to work for inspection. But any suggestions on what to check won't hurt. I'm going back out in a sec to check that there is really no power getting to them with the multimeter. I cant imagine there is a separate fuse for them.

Edit: checked these lights and the multimeter is showing a very low spike in voltage with the turn signals on, jumps from 0 to .1 or .15. Same thing if I ground directly to the battery negative. Going to take it for inspection anyway and hope this slides. Only 2 more years until this thing goes under antique vehicle rules.. yahoo

 

[renjaminfrankln]

Alright so it looks like these side marker lights do have to flash with the turn signal lights.

Anyone have suggestions of what to check before I buggar the wiring and just splice into the turn signal + so I can pass inspection tomorrow?