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Reverse Lights Not working

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Old Jun 11, 2014 | 05:02 PM
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Reverse Lights Not working

Before you say that I could have just searched this, I dont think I will find my answer.

My reverse lights are not working.

I have already checked the alignment of the neutral safety switch on the transmission

Checked the bulbs

Heres the interesting part.
I checked continuity as FMC400 told me to in this thread when I was working on getting one of the grille lights to work. https://www.ford-trucks.com/forums/showthread.php?t=1271475&styleid=20

When my multimeter touched the metal of the reverse light socket it sparked and blew the fuse. So now im not sure what I should do to try getting them to work. I dont want to keep having to replace the fuse.

Thanks for your help!
 
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Old Jun 11, 2014 | 05:21 PM
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Can you please provide more detail as to what you actually did? What does it mean to check the bulb, or the alignment of the NSS? Specifically, what do you consider acceptable test results?

For your multimeter problem, you'll have to be more specific. If one probe shorts both contacts (as is EXTREMELY easy to do probing inside a socket), it will blow a fuse. If the meter is set to measure current, it will blow a fuse. Note that this can only happen if there's power at the socket, which doesn't line up with you saying the backup lights don't work, but everything is "good" - hence my requiring you to clarify what you actually tested.
 
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Old Jun 11, 2014 | 05:40 PM
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Originally Posted by fmc400
Can you please provide more detail as to what you actually did? What does it mean to check the bulb, or the alignment of the NSS? Specifically, what do you consider acceptable test results?

For your multimeter problem, you'll have to be more specific. If one probe shorts both contacts (as is EXTREMELY easy to do probing inside a socket), it will blow a fuse. If the meter is set to measure current, it will blow a fuse. Note that this can only happen if there's power at the socket, which doesn't line up with you saying the backup lights don't work, but everything is "good" - hence my requiring you to clarify what you actually tested.
I checked the neutral safety switch by using a small allen wrench in the alignment hole of the NSS with the trans in neutral and moved the NSS until the allen wrench was able to go into the alignment hole. I then tightened the two bolts holding the switch down with the allen head still in the alignment hole i then checked if it would start in park or neutral only and it did. I then put the transmission in reverse with the engine running and they were still not working. Since the truck started in only park or neutral I figured that the NSS was working correctly

The multimeter was set to ohms and I had a nail in the clamp of the positive wire for the multimeter because my multimeter clamps are too big.

I grounded the negative wire for the multimeter to the screw that the sockets for taillights and reverse ground to.
 
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Old Jun 11, 2014 | 06:55 PM
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Are you sure that neutral is the correct gear for the alignment pin? I thought it was park, but I could be wrong. I've aligned it by the reverse lights, but that doesn't help in your case. I guess if it starts properly in the correct gears, then you're right after all. Good to know.

If you blew a fuse with your meter, go ahead and replace it. Unplug the NSS on the side of the transmission, then with the key in ACC, check for power on the WHITE with PURPLE stripe wire on the TRUCK connector.

The meter must be set to volts to check for voltage. Ohms is for measuring resistance. While ohms would have been the incorrect setting, it would not blow a fuse. You must have shorted the contacts in the socket.
 
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Old Jun 11, 2014 | 07:24 PM
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Originally Posted by fmc400

If you blew a fuse with your meter, go ahead and replace it. Unplug the NSS on the side of the transmission, then with the key in ACC, check for power on the WHITE with PURPLE stripe wire on the TRUCK connector.

The meter must be set to volts to check for voltage. Ohms is for measuring resistance. While ohms would have been the incorrect setting, it would not blow a fuse. You must have shorted the contacts in the socket.
Do you mean Yellow with Purple stripe? There is no white wire on it, if its the yellow with purple stripe then it has 12 volts to it.
 
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Old Jun 11, 2014 | 08:01 PM
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Just now tested the drivers side socket for resistance it measured about 20 OHMS

Passenger Side measured 15 OHMS

Good or Bad?
 
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Old Jun 11, 2014 | 08:08 PM
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Originally Posted by Mustangking1
Do you mean Yellow with Purple stripe? There is no white wire on it, if its the yellow with purple stripe then it has 12 volts to it.
No, it's WHITE with PURPLE stripe. Yours appears YELLOW with PURPLE stripe due to age. 12 volts is good; I assume you replaced the fuse.

Originally Posted by Mustangking1
Just now tested the drivers side socket for resistance it measured about 20 OHMS

Good or Bad?
I'm not sure why you keep sticking your multimeter in the socket and setting it to ohms. It's a meaningless number. Just stick to my instructions.

Next, with the truck OFF, set the parking brake, put the truck in reverse, and chock the wheels because you're going to get under the truck with it in gear. With the NSS still disconnected, check the resistance between the WHITE with PURPLE stripe, and BLACK with RED stripe wires coming from the SWITCH. It should be a short circuit, meaning the resistance is no more than that of your meter leads shorted together.
 
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Old Jun 11, 2014 | 08:20 PM
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How should I create the short curcuit?
 
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Old Jun 11, 2014 | 08:23 PM
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You don't have to do that. I use the term "short circuit" because the resistance measured between the two terminals I've specified should equal that of a short circuit, meaning zero ohms. In reality, it will be a small value because of your meter contacts. For example, your meter leads when pressed together will read something like 0.1 ohms. A good switch will also read 0.1 ohms when measured according to the steps I've outlined.
 
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Old Jun 11, 2014 | 08:31 PM
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Ok, which connector am supposed to be checking? The NSS or Truck?
 
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Old Jun 11, 2014 | 08:35 PM
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Specified in my next-to-last post:

Originally Posted by fmc400
Next, with the truck OFF, set the parking brake, put the truck in reverse, and chock the wheels because you're going to get under the truck with it in gear. With the NSS still disconnected, check the resistance between the WHITE with PURPLE stripe, and BLACK with RED stripe wires coming from the SWITCH. It should be a short circuit, meaning the resistance is no more than that of your meter leads shorted together.
 
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Old Jun 11, 2014 | 09:00 PM
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When I tested them they only moved the slightest bit (i have a analog meter)

Is that good or bad?
 
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Old Jun 12, 2014 | 07:38 AM
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If the meter was on the lowest possible scale, then your measurement indicates the switch is functioning properly. If the meter has settings for 2/20/200/2000, etc, it needs to be on "2." If it was not on "2," the measurement must be repeated. Sometimes the scale is marked X10, X100, etc. Whatever the case may be, the scale must be set to the smallest setting. Please confirm.

If the meter was set up correctly, check for power at the bulb sockets with the switch reconnected, key in ACC, and shifter in REVERSE. Measure the voltage between the center contact inside the socket, and the inner socket body to which the bulb shell makes contact.
 
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Old Jun 12, 2014 | 08:19 AM
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Multimeter was set on high, i am about to go retest.
 
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Old Jun 12, 2014 | 08:57 AM
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Tested the plug on low and got the same results as i did before. I then tested the reverse light sockets and they have zero volts.
 
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